Blog written by an engineer
https://blog.matthen.com/post/52899410622/when-designing-a-machine-its-better-to-mesh
blog.matthen.com
2013-06-13
Peter Vidani; Matthen
<div><div>
 
 <p></p><p>When designing a machine, it’s better to <strong>mesh gears together</strong> whose numbers of teeth <strong>don’t share a common factor</strong>. In the top pair, the gears have <strong>12 and 6</strong> teeth each, so the <strong>red defect</strong> on the right gear grinds on the left gear in two places. Because the gears in the bottom have <strong>coprime numbers</strong> of teeth (7 &amp; 5), the <strong>wear</strong> from the defect is <strong>spread evenly</strong> on the left gear. [<a href="https://href.li/?http://reprap.org/wiki/Gear_design#number_of_teeth">more</a>] [<a href="https://href.li/?http://pastebin.com/KwsV1Qvg">code</a>] </p>
 
 
 
 
 
 
 
 
 
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 # math
 # science
 # gif
 # engineering
 # gears
 # factors
 # numbers
 # animation
 # mathematics
 # maths
 # mathematica

 When designing a machine, it’s better to mesh gears together whose numbers of teeth don’t share a common factor. In the top pair, the gears have 12 and 6 teeth each, so the red defect on the right gear grinds on the left gear in two places. Because the gears in the bottom have coprime numbers of teeth (7 & 5), the wear from the defect is spread evenly on the left gear. [more] [code]

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 Theme: Linear by Peter Vidani
When designing a machine, it’s better to mesh gears together whose numbers of teeth don’t share a common factor. In the top pair, the gears have 12 and 6 teeth each, so the red defect on the right gear grinds on the left gear in two places. Because the gears in the bottom have coprime numbers of teeth (7 &amp; 5), the wear from the defect is spread evenly on the left gear. [more] [code]
blog.matthen.com
https://blog.matthen.com/post/52899410622/when-designing-a-machine-its-better-to-mesh
https://incoherency.co.uk/blog/stories/hanayama-cast-marble.html
James Stanley
2020-07-08
None
<div><div>
<p><small><i>Wed 8 July 2020</i></small><br />
<i>Tagged: <a href="../tags/puzzle.html">puzzle</a>, <a href="../tags/3dprinting.html">3dprinting</a></i></p><p><a href="https://hanayama-toys.com/product/cast-marble/">Cast Marble</a> is a mechanical puzzle sold by <a href="https://hanayama-toys.com/">Hanayama</a>.
It was invented by <a href="https://en.wikipedia.org/wiki/Bram_Cohen">Bram Cohen</a> (who you may recognise as the
inventor of <a href="https://en.wikipedia.org/wiki/BitTorrent">BitTorrent</a>) and <a href="http://oskarvandeventer.nl/">Oskar
van Deventer</a>, who has an interesting <a href="https://www.youtube.com/user/OskarPuzzle">YouTube channel</a> where he regularly posts
new puzzle designs.</p>
<p><a href="https://img.incoherency.co.uk/2765"></a></p>
<p>The puzzle is made of 4 parts, which are 2 identical copies of 2 types of part. 2 of the parts form a ball in the centre, and the other 2 form a box around the outside.
The goal is to separate all of the parts.</p>
<p>(<b>Spoiler alert:</b> this post is intended to reveal the working principles of this puzzle to an even greater extent than you are likely to have
discovered by merely solving it. Don't read on if you still want to solve the puzzle yourself. Remember that "knowing the solution
cannot be reversed".)</p>
<h2>Solution</h2>
<p>The solution is quite simple, although very hard to discover. You need to align the cut line on the ball with the cut lines on
the outer box, and then twist the whole thing apart. After half a rotation, the parts have drifted apart sideways and can then
be separated easily.</p>
<p></p>
<p>This seems a bit like half a turn on a screw thread, but unlike a screw thread it is
composed of 2 identical halves, rather than a male thread and a female thread. I initially thought that the centre of rotation of each part was inside the other part,
but actually they share a common centre of rotation, and it is a simple helix.</p>
<h2>Geometry</h2>
<p>This animation shows what we get by sweeping a rectangular profile through a helical path:</p>
<p><a href="https://img.incoherency.co.uk/2772"></a></p>
<p>If the centre line of the rectangular profile is collinear with the central axis, and the height of the rectangle
is half the pitch of the helix, then a length of the resulting shape takes up exactly half the volume of its bounding cylinder,
and 2 copies of it will thread together to form a solid cylinder without overlapping each other. This isn't just a trick of computer
graphics, it works in real life:</p>
<p><a href="https://img.incoherency.co.uk/2769"></a>
<a href="https://img.incoherency.co.uk/2763"></a></p>
<p>I don't know if this kind of shape has a name, I couldn't find one, but might not have known the right search
terms. I like to think of it as a "hermaphroditic screw thread".
It might be funny to make some real hermaphroditic screws, with proper screw heads, and use them to bolt stuff together.</p>
<p>This photograph shows how the puzzle parts share the hermaphroditic screw geometry:</p>
<p><a href="https://img.incoherency.co.uk/2762"></a></p>
<p>And we now see that the apparently complex surfaces of the puzzle parts are formed from just
a few primitive shapes!</p>
<h2>Reproduction</h2>
<p>I was surprised to find that the Hanayama Cast Marble uses a left-handed thread on its hermaphroditic screw. I'm not sure whether
this makes the puzzle easier to hold for a right-handed person, or harder to solve because people aren't used to
left-handed screw threads.</p>
<p>I measured the thread pitch by twisting the puzzle through half a turn and measuring the offset between the box parts, which was about 18 mm.
We then know that the thread pitch is twice this much, so the thread pitch is 36 mm.
It's a bit of a crude measurement but I think I got it right. It's close enough that the parts
fit together, anyway.</p>
<p>Once we understand this much, the design of the puzzle is mostly straightforward with <a href="https://en.wikipedia.org/wiki/Constructive_solid_geometry">CSG modelling</a>.</p>
<p>The ball parts are made by intersecting a sphere with the hermaphroditic screw.</p>
<p><a href="https://img.incoherency.co.uk/2773"></a></p>
<p>And the box parts are made by subtracting a sphere from a cuboid and then intersecting the result with the hermaphroditic screw.</p>
<p><a href="https://img.incoherency.co.uk/2774"></a></p>
<p>If you want to print your own copy, you can <a href="https://incoherency.co.uk/interest/cast-marble.tar.gz">download the STL files</a>.</p>
<p><a href="https://img.incoherency.co.uk/2764"></a></p>
<p>The parts created this way are mostly interchangeable with the original puzzle parts:</p>
<p><a href="https://img.incoherency.co.uk/2766"></a></p>
<p>Although the printed box is not quite symmetrical, because I obviously cut it from the wrong place
in the thread:</p>
<p><a href="https://img.incoherency.co.uk/2767"></a></p>
<h2>Rounded edge</h2>
<p>Having put the printed puzzle together, I discovered one extra trick up the Cast Marble's sleeve!</p>
<p>Part of the reason the Cast Marble is so difficult to solve is because the box parts can rotate
around the centre in a way that is not used in the solution:</p>
<p><a href="https://img.incoherency.co.uk/2775"></a></p>
<p>This is due to a rounded edge on the box parts, which does not naturally occur from the
basic shape of the puzzle:</p>
<p><a href="https://img.incoherency.co.uk/2776"></a></p>
<h2>More</h2>
<p>An interesting property of the hermaphroditic thread is that any 2 threads will fit together, provided they have the same pitch and profile,
<i>regardless of their diameter</i>!</p>
<p>This means we could use the hermaphroditic thread to cut anything into 2 parts in a way that allows them
to thread together. I tried to do this with a few models I found on Thingiverse but they had
quite a lot of triangles, and FreeCAD
exhausted my machine's available RAM and crashed before it completed the intersection. In principle it would work though.</p>
<p>In addition to extending up/down to infinity, we can also extend our helix
outwards (radially) to infinity. This leads to 2 identical half-universes that can be screwed together, which is
quite a bizarre concept to wrap your head around. It's surprising that it's even possible. I would be interested to
learn of any other ways of splitting an infinite space into 2 identical halves that can move but
also constrain each other, because they might lead to low-hanging fruit
for new puzzle designs.</p>
<p>It might be interesting to experiment with alternative thread profiles. You need the inner edge to be a straight line segment
collinear with the central axis, but there's no reason that the upper and lower edges of the profile need to be
straight. They can be whatever you want as long as they match:</p>
<p><a href="https://img.incoherency.co.uk/2777"></a>
</p><p>
<i>If you like my blog, please consider subscribing to the <a href="http://incoherency.co.uk/blog/rss.xml">RSS feed</a> or the mailing list:</i></p>
</div>||||I|||| James Stanley

 Home Best posts Projects About

 Secrets of the Hanayama Cast Marble

 Wed 8 July 2020
 Tagged: puzzle, 3dprinting

 Cast Marble is a mechanical puzzle sold by Hanayama. It was invented by Bram Cohen (who you may recognise as the inventor of BitTorrent) and Oskar van Deventer, who has an interesting YouTube channel where he regularly posts new puzzle designs.

 The puzzle is made of 4 parts, which are 2 identical copies of 2 types of part. 2 of the parts form a ball in the centre, and the other 2 form a box around the outside. The goal is to separate all of the parts.

 (Spoiler alert: this post is intended to reveal the working principles of this puzzle to an even greater extent than you are likely to have discovered by merely solving it. Don't read on if you still want to solve the puzzle yourself. Remember that "knowing the solution cannot be reversed".)

 Solution

 The solution is quite simple, although very hard to discover. You need to align the cut line on the ball with the cut lines on the outer box, and then twist the whole thing apart. After half a rotation, the parts have drifted apart sideways and can then be separated easily.

 This seems a bit like half a turn on a screw thread, but unlike a screw thread it is composed of 2 identical halves, rather than a male thread and a female thread. I initially thought that the centre of rotation of each part was inside the other part, but actually they share a common centre of rotation, and it is a simple helix.

 Geometry

 This animation shows what we get by sweeping a rectangular profile through a helical path:

 If the centre line of the rectangular profile is collinear with the central axis, and the height of the rectangle is half the pitch of the helix, then a length of the resulting shape takes up exactly half the volume of its bounding cylinder, and 2 copies of it will thread together to form a solid cylinder without overlapping each other. This isn't just a trick of computer graphics, it works in real life:

 I don't know if this kind of shape has a name, I couldn't find one, but might not have known the right search terms. I like to think of it as a "hermaphroditic screw thread". It might be funny to make some real hermaphroditic screws, with proper screw heads, and use them to bolt stuff together.

 This photograph shows how the puzzle parts share the hermaphroditic screw geometry:

 And we now see that the apparently complex surfaces of the puzzle parts are formed from just a few primitive shapes!

 Reproduction

 I was surprised to find that the Hanayama Cast Marble uses a left-handed thread on its hermaphroditic screw. I'm not sure whether this makes the puzzle easier to hold for a right-handed person, or harder to solve because people aren't used to left-handed screw threads.

 I measured the thread pitch by twisting the puzzle through half a turn and measuring the offset between the box parts, which was about 18 mm. We then know that the thread pitch is twice this much, so the thread pitch is 36 mm. It's a bit of a crude measurement but I think I got it right. It's close enough that the parts fit together, anyway.

 Once we understand this much, the design of the puzzle is mostly straightforward with CSG modelling.

 The ball parts are made by intersecting a sphere with the hermaphroditic screw.

 And the box parts are made by subtracting a sphere from a cuboid and then intersecting the result with the hermaphroditic screw.

 If you want to print your own copy, you can download the STL files.

 The parts created this way are mostly interchangeable with the original puzzle parts:

 Although the printed box is not quite symmetrical, because I obviously cut it from the wrong place in the thread:

 Rounded edge

 Having put the printed puzzle together, I discovered one extra trick up the Cast Marble's sleeve!

 Part of the reason the Cast Marble is so difficult to solve is because the box parts can rotate around the centre in a way that is not used in the solution:

 This is due to a rounded edge on the box parts, which does not naturally occur from the basic shape of the puzzle:

 More

 An interesting property of the hermaphroditic thread is that any 2 threads will fit together, provided they have the same pitch and profile, regardless of their diameter!

 This means we could use the hermaphroditic thread to cut anything into 2 parts in a way that allows them to thread together. I tried to do this with a few models I found on Thingiverse but they had quite a lot of triangles, and FreeCAD exhausted my machine's available RAM and crashed before it completed the intersection. In principle it would work though.

 In addition to extending up/down to infinity, we can also extend our helix outwards (radially) to infinity. This leads to 2 identical half-universes that can be screwed together, which is quite a bizarre concept to wrap your head around. It's surprising that it's even possible. I would be interested to learn of any other ways of splitting an infinite space into 2 identical halves that can move but also constrain each other, because they might lead to low-hanging fruit for new puzzle designs.

 It might be interesting to experiment with alternative thread profiles. You need the inner edge to be a straight line segment collinear with the central axis, but there's no reason that the upper and lower edges of the profile need to be straight. They can be whatever you want as long as they match:



 If you like my blog, please consider subscribing to the RSS feed or the mailing list: Subscribe
 james@incoherency.co.uk | [rss]

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 «prev random next»
Wed 8 July 2020  
Tagged: puzzle, 3dprinting    Cast Marble is a mechanical puzzle sold by Hanayama.
It was invented by Bram Cohen (who you may recognise as the
inventor of BitTorrent) and Oskar
van Deventer, who has an interesting YouTube channel where he regularly posts
new puzzle designs.
   
The puzzle is made of 4 parts, which are 2 identical copies of 2 types of part. 2 of the parts form a ball in the centre, and the other 2 form a box around the outside.
The goal is to separate all of the parts.
(Spoiler alert: this post is intended to reveal the working principles of this puzzle to an even greater extent than you are likely to have
discovered by merely solving it. Don't read on if you still want to solve the puzzle yourself. Remember that "knowing the solution
cannot be reversed".)
Solution
The solution is quite simple, although very hard to discover. You need to align the cut line on the ball with the cut lines on
the outer box, and then twist the whole thing apart. After half a rotation, the parts have drifted apart sideways and can then
be separated easily.
 
This seems a bit like half a turn on a screw thread, but unlike a screw thread it is
composed of 2 identical halves, rather than a male thread and a female thread. I initially thought that the centre of rotation of each part was inside the other part,
but actually they share a common centre of rotation, and it is a simple helix.
Geometry
This animation shows what we get by sweeping a rectangular profile through a helical path:
   
If the centre line of the rectangular profile is collinear with the central axis, and the height of the rectangle
is half the pitch of the helix, then a length of the resulting shape takes up exactly half the volume of its bounding cylinder,
and 2 copies of it will thread together to form a solid cylinder without overlapping each other. This isn't just a trick of computer
graphics, it works in real life:
  
  
I don't know if this kind of shape has a name, I couldn't find one, but might not have known the right search
terms. I like to think of it as a "hermaphroditic screw thread".
It might be funny to make some real hermaphroditic screws, with proper screw heads, and use them to bolt stuff together.
This photograph shows how the puzzle parts share the hermaphroditic screw geometry:
   
And we now see that the apparently complex surfaces of the puzzle parts are formed from just
a few primitive shapes!
Reproduction
I was surprised to find that the Hanayama Cast Marble uses a left-handed thread on its hermaphroditic screw. I'm not sure whether
this makes the puzzle easier to hold for a right-handed person, or harder to solve because people aren't used to
left-handed screw threads.
I measured the thread pitch by twisting the puzzle through half a turn and measuring the offset between the box parts, which was about 18 mm.
We then know that the thread pitch is twice this much, so the thread pitch is 36 mm.
It's a bit of a crude measurement but I think I got it right. It's close enough that the parts
fit together, anyway.
Once we understand this much, the design of the puzzle is mostly straightforward with CSG modelling.
The ball parts are made by intersecting a sphere with the hermaphroditic screw.
   
And the box parts are made by subtracting a sphere from a cuboid and then intersecting the result with the hermaphroditic screw.
   
If you want to print your own copy, you can download the STL files.
   
The parts created this way are mostly interchangeable with the original puzzle parts:
   
Although the printed box is not quite symmetrical, because I obviously cut it from the wrong place
in the thread:
   
Rounded edge
Having put the printed puzzle together, I discovered one extra trick up the Cast Marble's sleeve!
Part of the reason the Cast Marble is so difficult to solve is because the box parts can rotate
around the centre in a way that is not used in the solution:
   
This is due to a rounded edge on the box parts, which does not naturally occur from the
basic shape of the puzzle:
   
More
An interesting property of the hermaphroditic thread is that any 2 threads will fit together, provided they have the same pitch and profile,
regardless of their diameter!
This means we could use the hermaphroditic thread to cut anything into 2 parts in a way that allows them
to thread together. I tried to do this with a few models I found on Thingiverse but they had
quite a lot of triangles, and FreeCAD
exhausted my machine's available RAM and crashed before it completed the intersection. In principle it would work though.
In addition to extending up/down to infinity, we can also extend our helix
outwards (radially) to infinity. This leads to 2 identical half-universes that can be screwed together, which is
quite a bizarre concept to wrap your head around. It's surprising that it's even possible. I would be interested to
learn of any other ways of splitting an infinite space into 2 identical halves that can move but
also constrain each other, because they might lead to low-hanging fruit
for new puzzle designs.
It might be interesting to experiment with alternative thread profiles. You need the inner edge to be a straight line segment
collinear with the central axis, but there's no reason that the upper and lower edges of the profile need to be
straight. They can be whatever you want as long as they match:
  
 
If you like my blog, please consider subscribing to the RSS feed or the mailing list:
James Stanley
https://incoherency.co.uk/blog/stories/hanayama-cast-marble.html
http://www.ganssle.com/blog/blog/circuit-theory.html
Remembering Circuit Theory
2020-01-01
None
<div><section> 
 
 
 
 <div><p><i>For novel ideas about building embedded systems (both hardware and firmware), join the 40,000+ engineers who subscribe to <a href="http://www.ganssle.com/tem-subunsub.html">The Embedded Muse</a>, a free biweekly newsletter. The Muse has no hype and no vendor PR. <a href="http://www.ganssle.com/tem-subunsub.html">Click here to subscribe.</a></i><br />
 </p>
</div>
<h2>Remembering Circuit Theory</h2>
 <pre>December 27, 2018 </pre>
 <p>For those of you who studied electrical engineering in college, remember the circuit theory course?</p>
 <p>It has been almost half a century since I took that class, and my memories of it are vague. But I find electronics fun and fascinating, so thought it might be worthwhile to revisit that material. Lord knows what happened to most of my college textbooks, so I ordered <em>Circuit Analysis, Theory and Practice</em> (by Robbins and Miller) from Abebooks. It's a thousand-page tome that must weigh in at over five pounds. The price (used): $3.70, with free shipping. What a deal! I can't imagine how they make any money on it.</p>
 <p>I'm 600 pages in at the moment and have been surprised and gratified to find I remember most of the material. Norton's and Thevenin's Theorems, Kirchhoff's Laws, and more still lurked in these decaying gray cells.</p>
 <p>Yet in 45 years of being a practicing EE I've never once used these fundamental principles. They're good to know, and foundational to analyzing circuit networks. It's like knowing how to integrate a simple differential equation to get the formula for an RC time constant… but in practice, in the real world, one only uses the resultant formula:</p>
 <p></p>
<p>Then, in AC circuits, there are phasors. No, not the kind Captain Kirk uses against the Klingons (and which are spelled "phaser"), but the rotating vectors used to represent phase and magnitude of a sine wave. A rotating vector? Doesn't that sort of break the rules of vectors, which are entities that have magnitude and direction? Well, at any point in time a phasor does have those properties. I don't think I really understood them while struggling through that class. Now they make sense, but still seem quite cumbersome compared to the trig: </p>
 <p>
 </p><p>I have to convert a phasor expression to the trig to solve real-world problems, but that could be a flaw in my understanding.</p>
 <p>Though I've used the trig formulation thousands of time in my career, I've never used the phasor representation.</p>
 <p>Then there are the problems students need to solve. Every chapter ends with a lot of these, some of which are incredibly convoluted. THAT I remember: for instance, reducing some absurd network of resistors to one equivalent value. Jeez, the profs made us burn some serious brain cells doing this. Here's an example problem from the book:</p>
 <p>
 </p><p>Perhaps young, malleable minds need to struggle through the contortions needed to reduce this to a single equivalent resistor. Perhaps doing so drives the basic ideas of series and parallel resistors indelibly into a budding engineer's psyche. </p>
 <p>In the real world I've used the classic formula for two resistors in parallel a zillion times:</p>
 <p>
 </p><p>And the more generalized one for many resistors a few times:</p>
 <p>
 </p><p>But to solve for a nasty resistor network like the one above? Never. Need a resistor? Calculate the required value, check the Digi-Key site, and buy one with the closest value to that required. Problem solved.</p>
 <p>Then there was that statics class. That was tough. The next semester things got so much worse in dynamics where everything was moving! Ironically, I do use statics a lot, but for computing loads on my sailboat or moving logs around the yard. Never in electrical engineering.</p>
 <p>I was an electronics nerd long before starting at the University of Maryland and found that the formal education gave a theoretical grounding to the practical knowledge gleaned from years of messing about with circuits. I do appreciate those years suffering under the tutelage of the academics. </p>
 <p>One of the best books on electronics is <em>The Art of Electronics</em> by Horowitz and Hill. It's very practical and written to appeal to people who design things. It's short on theory; you won't find a complex number anywhere. So I'm tremendously enjoying <em>Circuit Theory</em> which is the philosophical conjugate to of the <em>H&amp;H</em> book, sort of existing on the j axis while <em>H&amp;H</em> are in the real domain.</p><p>Feel free to <a href="mailto:jack@ganssle.com">email</a> me with comments. </p>
 
 <p><em>If you'd like to post a comment without logging in, click in the "Name" box under "Or sign up with Disqus" and click on "I'd rather post as a guest."</em></p>
<h2>Recent blog postings:</h2>
<ul>
 <li><a href="http://www.ganssle.com/blog/blog/non-compos-mentis.html">Non Compos Mentis</a> - Thoughts on dementia.</li>
<li><a href="http://www.ganssle.com/blog/blog/chip-shortage.html">Solution to the Automotive Chip Shortage</a> - why use an MCU when a Core I7 would work?  </li>
<li><a href="http://www.ganssle.com/blog/blog/wirecare.html">The WIRECARE</a> - A nice circuit tester</li>
<li><a href="http://www.ganssle.com/blog/blog/marvelous-magnetic-machines.html">Marvelous Magnetic Machines</a> - A cool book about making motors</li>
 <li><a href="http://www.ganssle.com/blog/blog/gps-outages.html">Over-Reliance on GPS</a> - It's a great system but is a single point of failure</li>
 <li><a href="http://www.ganssle.com/blog/blog/spies-in-our-email.html">Spies in Our Email </a>- Email abuse from our trusted friends</li>
 <li><a href="http://www.ganssle.com/blog/blog/a-canticle-for-leibowitz.html">A Canticle for Leibowitz</a> - One of my favorite books.</li>
 <li><a href="http://www.ganssle.com/blog/blog/heart-rate.html">A 72123 beats per minute heart rate</a> - Is it possible?</li>
 <li><a href="http://www.ganssle.com/blog/blog/on-networking.html">Networking Did Not Start With The IoT!</a> - Despite what the marketing folks claim</li>
 <li><a href="http://www.ganssle.com/blog/blog/in-circuit-emulators.html">In-Circuit Emulators</a> - Does anyone remember ICEs?</li>
 <li><a href="http://www.ganssle.com/blog/blog/gp-8e.html">My GP-8E Computer</a> - About my first (working!) computer</li>
 <li><a href="http://www.ganssle.com/blog/blog/humility.html">Humility</a> - On <em>The Death of Expertise</em> and what this means for engineering</li>
 <li><a href="http://www.ganssle.com/blog/blog/checklists.html">On Checklists</a> - Relying on memory is a fool's errand. Effective people use checklists.</li>
 <li><a href="http://www.ganssle.com/blog/blog/why-does-software-cost-so-much.html">Why Does Software Cost So Much?</a> - An exploration of this nagging question.</li>
 <li><a href="http://www.ganssle.com/blog/blog/its-not-all-linux.html">Is the Future All Linux and Raspberry Pi?</a> - Will we stop slinging bits and diddling registers?</li>
 <li><a href="http://www.ganssle.com/blog/blog/end-of-open-offices.html">Will Coronavirus Spell the End of Open Offices</a> - How can we continue to work in these sorts of conditions?</li>
 <li><a href="http://www.ganssle.com/blog/blog/ventilators.html">Problems in Ramping Up Ventilator Production</a> - It's not as easy as some think.</li>
 <li><a href="http://www.ganssle.com/blog/blog/car-wash-fail.html">Lessons from a Failure</a> - what we can learn when a car wash goes wrong.</li>
 <li><a href="http://www.ganssle.com/blog/blog/life-in-the-time-of-coronavirus.html">Life in the Time of Coronavirus</a> - how are you faring?</li>
 <li><a href="http://www.ganssle.com/blog/blog/superintelligence.html">Superintelligence</a> - A review of Nick Bostrom's book on AI.</li>
 <li><a href="http://www.ganssle.com/blog/blog/a-lack-of-forethought.html">A Lack of Forethought </a>- Y2K redux</li>
 <li><a href="http://www.ganssle.com/blog/blog/how-projects-get-out-of-control.html">How Projects Get Out of Control</a> - Think requirements churn is only for software?</li>
 <li><a href="http://www.ganssle.com/blog/blog/737-disaster.html">2019's Most Important Lesson</a>. The 737 Max disasters should teach us one lesson.</li>
 <li><a href="http://www.ganssle.com/blog/blog/on-retiring.html">On Retiring</a> - It's not quite that time, but slowing down makes sense. For me.</li>
 <li><a href="http://www.ganssle.com/blog/blog/on-discipline.html">On Discipline</a> - The one thing I think many teams need...</li>
 <li><a href="http://www.ganssle.com/blog/blog/backups.html">Data Seems to Have No Value</a> - At least, that's the way people treat it.</li>
 <li><a href="/blog/blog/celestial.html">Apollo 11 and Navigation</a> - In 1969 the astronauts used a sextant. Some of us still do.</li>
 <li><a href="http://www.ganssle.com/blog/blog/definitions-part-2.html">Definitions Part 2</a> - More fun definitions of embedded systems terms.</li>
 <li><a href="http://www.ganssle.com/blog/blog/definitions.html">Definitions</a> - A list of (funny) definitions of embedded systems terms.</li>
 <li><a href="http://www.ganssle.com/blog/blog/meta-politics.html">On Meta-Politics</a> - Where has thoughtful discourse gone?</li>
 <li><a href="http://www.ganssle.com/blog/blog/millennials-and-tools.html">Millennials and Tools</a> - It seems that many millennials are unable to fix anything.</li>
 <li><a href="http://www.ganssle.com/blog/blog/crappy-tech-journalism.html">Crappy Tech Journalism</a> - The trade press is suffering from so much cost-cutting that it does a poor job of educating engineers.</li>
 <li><a href="http://www.ganssle.com/blog/blog/tech-and-us.html">Tech and Us</a> - I worry that our technology is more than our human nature can manage.</li>
 <li><a href="http://www.ganssle.com/blog/blog/on-cataracts.html">On Cataracts</a> - Cataract surgery isn't as awful as it sounds.</li>
 <li><a href="http://www.ganssle.com/blog/blog/can-ai-replace-firmware.html">Can AI Replace Firmware</a> - A thought: instead of writing code, is the future training AIs?</li>
 <li><a href="http://www.ganssle.com/blog/blog/customer-non-support.html">Customer non-Support</a> - How to tick off your customers in one easy lesson.</li>
 <li><a href="http://www.ganssle.com/blog/blog/coder-or-engineer.html">Learn to Code in 3 Weeks!</a> - Firmware is not simply about coding.</li>
 <li><a href="http://www.ganssle.com/blog/blog/we-shoot-for-the-moon.html">We Shoot For The Moon</a> - a new and interesting book about the Apollo moon program.</li>
 <li><a href="http://www.ganssle.com/blog/blog/expert-witness.html">On Expert Witness Work</a> - Expert work is fascinating but can be quite the hassle.</li>
 <li><a href="http://www.ganssle.com/blog/blog/married-to-the-team.html">Married To The Team</a> - Working in a team is a lot like marriage.</li>
 <li><a href="http://www.ganssle.com/blog/blog/will-we-ever-get-quantum-computers.html">Will We Ever Get Quantum Computers</a> - Despite the hype, some feel quantum computing may never be practical.</li>
 <li><a href="http://www.ganssle.com/blog/blog/apollo-11-the-movie.html">Apollo 11, The Movie</a> - A review of a great new movie.</li>
 <li><a href="http://www.ganssle.com/blog/blog/goto-considered-needed.html">Goto Considered Necessary</a> - Edsger Dijkstra recants on his seminal paper</li>
 <li><a href="/blog/blog/gps-will-fail.html">GPS Will Fail </a>- In April GPS will have its own Y2K problem. Unbelievable.</li>
 <li><a href="http://www.ganssle.com/blog/blog/lidar-in-cars.html">LIDAR in Cars - Really?</a> - Maybe there are better ideas.</li>
 <li><a href="http://www.ganssle.com/blog/blog/why-i-became-an-engineer.html">Why Did You Become an Engineer?</a> - This is the best career ever.</li>
 <li><a href="http://www.ganssle.com/blog/blog/on-software-process-improvement.html">Software Process Improvement for Firmware</a> - What goes on in an SPI audit?</li>
 <li><a href="http://www.ganssle.com/blog/blog/50-years-a-ham.html">50 Years of Ham Radio</a> - 2019 marks 50 years of ham radio for me.</li>
 <li><a href="http://www.ganssle.com/blog/blog/medical-device-lawsuits.html">Medical Device Lawsuits</a> - They're on the rise, and firmware is part of the problem.</li>
 <li><a href="http://www.ganssle.com/blog/blog/a-retrospective-on-2018.html">A retrospective on 2018</a> - My marketing data for 2018, including web traffic and TEM information.</li>
 <li><a href="http://www.ganssle.com/blog/blog/circuit-theory.html">Remembering Circuit Theory</a> - Electronics is fun, and reviewing a textbook is pretty interesting.</li>
 <li><a href="http://www.ganssle.com/blog/blog/r-vs-d.html">R vs D</a> - Too many of us conflate research and development</li>
 <li><a href="http://www.ganssle.com/blog/blog/engineer-or-scientist.html">Engineer or Scientist?</a> - Which are you? John Q. Public has a hard time telling the difference.</li>
 <li><a href="http://www.ganssle.com/blog/blog/doorstop-pc.html">A New, Low-Tech, Use for Computers</a> - I never would have imagined this use for computers.</li>
 <li><a href="http://www.ganssle.com/blog/blog/nasa-lost-software-lessons.html">NASA's Lost Software Engineering Lessons</a> - Lessons learned, lessons lost.</li>
 <li><a href="http://www.ganssle.com/blog/blog/the-cost-of-firmware.html">The Cost of Firmware - A Scary Story!</a> - A hallowean story to terrify.</li>
 <li><a href="http://www.ganssle.com/blog/blog/first-man-a-bust-of-a-movie.html">A Review of First Man, the Movie</a> - The book was great. The movie? Nope.</li>
 <li><a href="http://www.ganssle.com/blog/blog/the-overstory.html">A Review of The Overstory</a> - One of the most remarkable novels I've read in a long time.</li>
 <li><a href="http://www.ganssle.com/blog/blog/what-i-learned-about-consulting.html">What I Learned About Successful Consulting</a> - Lessons learned about successful consulting.</li>
 <li><a href="http://www.ganssle.com/blog/blog/low-power-mischief.html">Low Power Mischief</a> - Ultra-low power systems are trickier to design than most realize.</li>
 <li><a href="http://www.ganssle.com/blog/blog/thoughts-on-firmware-seminars.html">Thoughts on Firmware Seminars</a> - Better Firmware Faster resonates with a lot of people.</li>
 <li><a href="http://www.ganssle.com/blog/blog/on-evil.html">On Evil</a> - The Internet has brought the worst out in many.</li>
 <li><a href="http://www.ganssle.com/blog/blog/my-toothbrush-has-modes.html">My Toothbrush has Modes</a> - What! A lousy toothbrush has a UI?</li>
 <li><a href="http://www.ganssle.com/blog/blog/sunburst-and-luminary.html">Review of SUNBURST and LUMINARY: An Apollo Memoir</a> - A good book about the LM's code.</li>
 <li><a href="http://www.ganssle.com/blog/blog/fun-with-transmission-lines.html">Fun With Transmission Lines</a> - Generating a step with no electronics.</li>
 <li><a href="http://www.ganssle.com/blog/blog/on-n-version-programming.html">On N-Version Programming</a> - Can we improve reliability through redundancy? Maybe not.</li>
 <li><a href="http://www.ganssle.com/blog/blog/on-usb-v-bench-scopes.html">On USB v. Bench Scopes</a> - USB scopes are nice, but I'll stick with bench models. </li>
</ul>
 
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 Jack Ganssle's Blog    
 This is Jack's outlet for thoughts about designing and programming embedded systems. It's a complement to my bi-weekly newsletter The Embedded Muse. Contact me at jack@ganssle.com. I'm an old-timer engineer who still finds the field endlessly fascinating (bio).
 
 For novel ideas about building embedded systems (both hardware and firmware), join the 40,000+ engineers who subscribe to The Embedded Muse, a free biweekly newsletter. The Muse has no hype and no vendor PR. Click here to subscribe.
    
 

 Remembering Circuit Theory

 December 27, 2018 

 For those of you who studied electrical engineering in college, remember the circuit theory course?

 It has been almost half a century since I took that class, and my memories of it are vague. But I find electronics fun and fascinating, so thought it might be worthwhile to revisit that material. Lord knows what happened to most of my college textbooks, so I ordered Circuit Analysis, Theory and Practice (by Robbins and Miller) from Abebooks. It's a thousand-page tome that must weigh in at over five pounds. The price (used): $3.70, with free shipping. What a deal! I can't imagine how they make any money on it.

 I'm 600 pages in at the moment and have been surprised and gratified to find I remember most of the material. Norton's and Thevenin's Theorems, Kirchhoff's Laws, and more still lurked in these decaying gray cells.

 Yet in 45 years of being a practicing EE I've never once used these fundamental principles. They're good to know, and foundational to analyzing circuit networks. It's like knowing how to integrate a simple differential equation to get the formula for an RC time constant… but in practice, in the real world, one only uses the resultant formula:

 Then, in AC circuits, there are phasors. No, not the kind Captain Kirk uses against the Klingons (and which are spelled "phaser"), but the rotating vectors used to represent phase and magnitude of a sine wave. A rotating vector? Doesn't that sort of break the rules of vectors, which are entities that have magnitude and direction? Well, at any point in time a phasor does have those properties. I don't think I really understood them while struggling through that class. Now they make sense, but still seem quite cumbersome compared to the trig:

 I have to convert a phasor expression to the trig to solve real-world problems, but that could be a flaw in my understanding.

 Though I've used the trig formulation thousands of time in my career, I've never used the phasor representation.

 Then there are the problems students need to solve. Every chapter ends with a lot of these, some of which are incredibly convoluted. THAT I remember: for instance, reducing some absurd network of resistors to one equivalent value. Jeez, the profs made us burn some serious brain cells doing this. Here's an example problem from the book:

 Perhaps young, malleable minds need to struggle through the contortions needed to reduce this to a single equivalent resistor. Perhaps doing so drives the basic ideas of series and parallel resistors indelibly into a budding engineer's psyche.

 In the real world I've used the classic formula for two resistors in parallel a zillion times:

 And the more generalized one for many resistors a few times:

 But to solve for a nasty resistor network like the one above? Never. Need a resistor? Calculate the required value, check the Digi-Key site, and buy one with the closest value to that required. Problem solved.

 Then there was that statics class. That was tough. The next semester things got so much worse in dynamics where everything was moving! Ironically, I do use statics a lot, but for computing loads on my sailboat or moving logs around the yard. Never in electrical engineering.

 I was an electronics nerd long before starting at the University of Maryland and found that the formal education gave a theoretical grounding to the practical knowledge gleaned from years of messing about with circuits. I do appreciate those years suffering under the tutelage of the academics.

 One of the best books on electronics is The Art of Electronics by Horowitz and Hill. It's very practical and written to appeal to people who design things. It's short on theory; you won't find a complex number anywhere. So I'm tremendously enjoying Circuit Theory which is the philosophical conjugate to of the H&H book, sort of existing on the j axis while H&H are in the real domain.

 Feel free to email me with comments.

 If you'd like to post a comment without logging in, click in the "Name" box under "Or sign up with Disqus" and click on "I'd rather post as a guest."

 Please enable JavaScript to view the comments powered by Disqus.

 Recent blog postings:

 * Non Compos Mentis - Thoughts on dementia.
 * Solution to the Automotive Chip Shortage - why use an MCU when a Core I7 would work?
 * The WIRECARE - A nice circuit tester
 * Marvelous Magnetic Machines - A cool book about making motors
 * Over-Reliance on GPS - It's a great system but is a single point of failure
 * Spies in Our Email - Email abuse from our trusted friends
 * A Canticle for Leibowitz - One of my favorite books.
 * A 72123 beats per minute heart rate - Is it possible?
 * Networking Did Not Start With The IoT! - Despite what the marketing folks claim
 * In-Circuit Emulators - Does anyone remember ICEs?
 * My GP-8E Computer - About my first (working!) computer
 * Humility - On The Death of Expertise and what this means for engineering
 * On Checklists - Relying on memory is a fool's errand. Effective people use checklists.
 * Why Does Software Cost So Much? - An exploration of this nagging question.
 * Is the Future All Linux and Raspberry Pi? - Will we stop slinging bits and diddling registers?
 * Will Coronavirus Spell the End of Open Offices - How can we continue to work in these sorts of conditions?
 * Problems in Ramping Up Ventilator Production - It's not as easy as some think.
 * Lessons from a Failure - what we can learn when a car wash goes wrong.
 * Life in the Time of Coronavirus - how are you faring?
 * Superintelligence - A review of Nick Bostrom's book on AI.
 * A Lack of Forethought - Y2K redux
 * How Projects Get Out of Control - Think requirements churn is only for software?
 * 2019's Most Important Lesson. The 737 Max disasters should teach us one lesson.
 * On Retiring - It's not quite that time, but slowing down makes sense. For me.
 * On Discipline - The one thing I think many teams need...
 * Data Seems to Have No Value - At least, that's the way people treat it.
 * Apollo 11 and Navigation - In 1969 the astronauts used a sextant. Some of us still do.
 * Definitions Part 2 - More fun definitions of embedded systems terms.
 * Definitions - A list of (funny) definitions of embedded systems terms.
 * On Meta-Politics - Where has thoughtful discourse gone?
 * Millennials and Tools - It seems that many millennials are unable to fix anything.
 * Crappy Tech Journalism - The trade press is suffering from so much cost-cutting that it does a poor job of educating engineers.
 * Tech and Us - I worry that our technology is more than our human nature can manage.
 * On Cataracts - Cataract surgery isn't as awful as it sounds.
 * Can AI Replace Firmware - A thought: instead of writing code, is the future training AIs?
 * Customer non-Support - How to tick off your customers in one easy lesson.
 * Learn to Code in 3 Weeks! - Firmware is not simply about coding.
 * We Shoot For The Moon - a new and interesting book about the Apollo moon program.
 * On Expert Witness Work - Expert work is fascinating but can be quite the hassle.
 * Married To The Team - Working in a team is a lot like marriage.
 * Will We Ever Get Quantum Computers - Despite the hype, some feel quantum computing may never be practical.
 * Apollo 11, The Movie - A review of a great new movie.
 * Goto Considered Necessary - Edsger Dijkstra recants on his seminal paper
 * GPS Will Fail - In April GPS will have its own Y2K problem. Unbelievable.
 * LIDAR in Cars - Really? - Maybe there are better ideas.
 * Why Did You Become an Engineer? - This is the best career ever.
 * Software Process Improvement for Firmware - What goes on in an SPI audit?
 * 50 Years of Ham Radio - 2019 marks 50 years of ham radio for me.
 * Medical Device Lawsuits - They're on the rise, and firmware is part of the problem.
 * A retrospective on 2018 - My marketing data for 2018, including web traffic and TEM information.
 * Remembering Circuit Theory - Electronics is fun, and reviewing a textbook is pretty interesting.
 * R vs D - Too many of us conflate research and development
 * Engineer or Scientist? - Which are you? John Q. Public has a hard time telling the difference.
 * A New, Low-Tech, Use for Computers - I never would have imagined this use for computers.
 * NASA's Lost Software Engineering Lessons - Lessons learned, lessons lost.
 * The Cost of Firmware - A Scary Story! - A hallowean story to terrify.
 * A Review of First Man, the Movie - The book was great. The movie? Nope.
 * A Review of The Overstory - One of the most remarkable novels I've read in a long time.
 * What I Learned About Successful Consulting - Lessons learned about successful consulting.
 * Low Power Mischief - Ultra-low power systems are trickier to design than most realize.
 * Thoughts on Firmware Seminars - Better Firmware Faster resonates with a lot of people.
 * On Evil - The Internet has brought the worst out in many.
 * My Toothbrush has Modes - What! A lousy toothbrush has a UI?
 * Review of SUNBURST and LUMINARY: An Apollo Memoir - A good book about the LM's code.
 * Fun With Transmission Lines - Generating a step with no electronics.
 * On N-Version Programming - Can we improve reliability through redundancy? Maybe not.
 * On USB v. Bench Scopes - USB scopes are nice, but I'll stick with bench models.

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For novel ideas about building embedded systems (both hardware and firmware), join the 40,000+ engineers who subscribe to The Embedded Muse, a free biweekly newsletter. The Muse has no hype and no vendor PR. Click here to subscribe.  
 
Remembering Circuit Theory
 December 27, 2018 
 For those of you who studied electrical engineering in college, remember the circuit theory course?
 It has been almost half a century since I took that class, and my memories of it are vague. But I find electronics fun and fascinating, so thought it might be worthwhile to revisit that material. Lord knows what happened to most of my college textbooks, so I ordered Circuit Analysis, Theory and Practice (by Robbins and Miller) from Abebooks. It's a thousand-page tome that must weigh in at over five pounds. The price (used): $3.70, with free shipping. What a deal! I can't imagine how they make any money on it.
 I'm 600 pages in at the moment and have been surprised and gratified to find I remember most of the material. Norton's and Thevenin's Theorems, Kirchhoff's Laws, and more still lurked in these decaying gray cells.
 Yet in 45 years of being a practicing EE I've never once used these fundamental principles. They're good to know, and foundational to analyzing circuit networks. It's like knowing how to integrate a simple differential equation to get the formula for an RC time constant… but in practice, in the real world, one only uses the resultant formula:
  
Then, in AC circuits, there are phasors. No, not the kind Captain Kirk uses against the Klingons (and which are spelled "phaser"), but the rotating vectors used to represent phase and magnitude of a sine wave. A rotating vector? Doesn't that sort of break the rules of vectors, which are entities that have magnitude and direction? Well, at any point in time a phasor does have those properties. I don't think I really understood them while struggling through that class. Now they make sense, but still seem quite cumbersome compared to the trig: 
 
  I have to convert a phasor expression to the trig to solve real-world problems, but that could be a flaw in my understanding.
 Though I've used the trig formulation thousands of time in my career, I've never used the phasor representation.
 Then there are the problems students need to solve. Every chapter ends with a lot of these, some of which are incredibly convoluted. THAT I remember: for instance, reducing some absurd network of resistors to one equivalent value. Jeez, the profs made us burn some serious brain cells doing this. Here's an example problem from the book:
 
  Perhaps young, malleable minds need to struggle through the contortions needed to reduce this to a single equivalent resistor. Perhaps doing so drives the basic ideas of series and parallel resistors indelibly into a budding engineer's psyche. 
 In the real world I've used the classic formula for two resistors in parallel a zillion times:
 
  And the more generalized one for many resistors a few times:
 
  But to solve for a nasty resistor network like the one above? Never. Need a resistor? Calculate the required value, check the Digi-Key site, and buy one with the closest value to that required. Problem solved.
 Then there was that statics class. That was tough. The next semester things got so much worse in dynamics where everything was moving! Ironically, I do use statics a lot, but for computing loads on my sailboat or moving logs around the yard. Never in electrical engineering.
 I was an electronics nerd long before starting at the University of Maryland and found that the formal education gave a theoretical grounding to the practical knowledge gleaned from years of messing about with circuits. I do appreciate those years suffering under the tutelage of the academics. 
 One of the best books on electronics is The Art of Electronics by Horowitz and Hill. It's very practical and written to appeal to people who design things. It's short on theory; you won't find a complex number anywhere. So I'm tremendously enjoying Circuit Theory which is the philosophical conjugate to of the H&amp;H book, sort of existing on the j axis while H&amp;H are in the real domain. Feel free to email me with comments. 
 
  If you'd like to post a comment without logging in, click in the "Name" box under "Or sign up with Disqus" and click on "I'd rather post as a guest." 
Recent blog postings:
  Non Compos Mentis - Thoughts on dementia.
 Solution to the Automotive Chip Shortage - why use an MCU when a Core I7 would work?  
 The WIRECARE - A nice circuit tester
 Marvelous Magnetic Machines - A cool book about making motors
  Over-Reliance on GPS - It's a great system but is a single point of failure
  Spies in Our Email - Email abuse from our trusted friends
  A Canticle for Leibowitz - One of my favorite books.
  A 72123 beats per minute heart rate - Is it possible?
  Networking Did Not Start With The IoT! - Despite what the marketing folks claim
  In-Circuit Emulators - Does anyone remember ICEs?
  My GP-8E Computer - About my first (working!) computer
  Humility - On The Death of Expertise and what this means for engineering
  On Checklists - Relying on memory is a fool's errand. Effective people use checklists.
  Why Does Software Cost So Much? - An exploration of this nagging question.
  Is the Future All Linux and Raspberry Pi? - Will we stop slinging bits and diddling registers?
  Will Coronavirus Spell the End of Open Offices - How can we continue to work in these sorts of conditions?
  Problems in Ramping Up Ventilator Production - It's not as easy as some think.
  Lessons from a Failure - what we can learn when a car wash goes wrong.
  Life in the Time of Coronavirus - how are you faring?
  Superintelligence - A review of Nick Bostrom's book on AI.
  A Lack of Forethought - Y2K redux
  How Projects Get Out of Control - Think requirements churn is only for software?
  2019's Most Important Lesson. The 737 Max disasters should teach us one lesson.
  On Retiring - It's not quite that time, but slowing down makes sense. For me.
  On Discipline - The one thing I think many teams need...
  Data Seems to Have No Value - At least, that's the way people treat it.
  Apollo 11 and Navigation - In 1969 the astronauts used a sextant. Some of us still do.
  Definitions Part 2 - More fun definitions of embedded systems terms.
  Definitions - A list of (funny) definitions of embedded systems terms.
  On Meta-Politics - Where has thoughtful discourse gone?
  Millennials and Tools - It seems that many millennials are unable to fix anything.
  Crappy Tech Journalism - The trade press is suffering from so much cost-cutting that it does a poor job of educating engineers.
  Tech and Us - I worry that our technology is more than our human nature can manage.
  On Cataracts - Cataract surgery isn't as awful as it sounds.
  Can AI Replace Firmware - A thought: instead of writing code, is the future training AIs?
  Customer non-Support - How to tick off your customers in one easy lesson.
  Learn to Code in 3 Weeks! - Firmware is not simply about coding.
  We Shoot For The Moon - a new and interesting book about the Apollo moon program.
  On Expert Witness Work - Expert work is fascinating but can be quite the hassle.
  Married To The Team - Working in a team is a lot like marriage.
  Will We Ever Get Quantum Computers - Despite the hype, some feel quantum computing may never be practical.
  Apollo 11, The Movie - A review of a great new movie.
  Goto Considered Necessary - Edsger Dijkstra recants on his seminal paper
  GPS Will Fail - In April GPS will have its own Y2K problem. Unbelievable.
  LIDAR in Cars - Really? - Maybe there are better ideas.
  Why Did You Become an Engineer? - This is the best career ever.
  Software Process Improvement for Firmware - What goes on in an SPI audit?
  50 Years of Ham Radio - 2019 marks 50 years of ham radio for me.
  Medical Device Lawsuits - They're on the rise, and firmware is part of the problem.
  A retrospective on 2018 - My marketing data for 2018, including web traffic and TEM information.
  Remembering Circuit Theory - Electronics is fun, and reviewing a textbook is pretty interesting.
  R vs D - Too many of us conflate research and development
  Engineer or Scientist? - Which are you? John Q. Public has a hard time telling the difference.
  A New, Low-Tech, Use for Computers - I never would have imagined this use for computers.
  NASA's Lost Software Engineering Lessons - Lessons learned, lessons lost.
  The Cost of Firmware - A Scary Story! - A hallowean story to terrify.
  A Review of First Man, the Movie - The book was great. The movie? Nope.
  A Review of The Overstory - One of the most remarkable novels I've read in a long time.
  What I Learned About Successful Consulting - Lessons learned about successful consulting.
  Low Power Mischief - Ultra-low power systems are trickier to design than most realize.
  Thoughts on Firmware Seminars - Better Firmware Faster resonates with a lot of people.
  On Evil - The Internet has brought the worst out in many.
  My Toothbrush has Modes - What! A lousy toothbrush has a UI?
  Review of SUNBURST and LUMINARY: An Apollo Memoir - A good book about the LM's code.
  Fun With Transmission Lines - Generating a step with no electronics.
  On N-Version Programming - Can we improve reliability through redundancy? Maybe not.
  On USB v. Bench Scopes - USB scopes are nice, but I'll stick with bench models.
Remembering Circuit Theory
http://www.ganssle.com/blog/blog/circuit-theory.html
https://blog.aaronbieber.com/2021/04/23/blinding-my-roomba.html
Blinding My Roomba
2021-04-23
Aaron Bieber
<div><div>
 
 <p>I got a Roomba, which is pretty neat, but it’s also pretty stupid. As it turns
out, it works better for me if it’s crippled and I’m going to tell you how I did
it. And why; I’ll also tell you why.</p>
<p>This is a story about an iRobotÂ® RoombaÂ® 675 Wi-FiÂ® Connected Robot Vacuum, an
array of infrared “cliff” sensors, and a man who is fed up with their bullshit.</p>
<p>I purchased a Roomba because my wife has been begging for one for years, but
until now I couldn’t justify the price. At this point, there are so many robot
vacuums on the market you can find one to suit whatever your needs or budget may
be, but rather than spending time discovering available features and considering
my needs and wants, I just bought The Wirecutter’s top-rated model, which is the
<a href="https://amzn.to/3tKUHXP">iRobot Roomba 675</a>.</p>
<p>The Wirecutter advises that you can likely get by with the 614, which doesn’t
have Wi-Fi, but I wanted to be able to schedule when it will do its thing, so I
paid a bit more. As I write this, Amazon is selling the 675 for the <em>same price</em>
as the 614, so watch for those sales!</p>
<p>Long story short, the Roomba actually works better than I thought it would. It
picks up <em>a lot</em> of crumbs and dirt, and I can tell from just looking at our
living room rug whether it’s been around or not. But let’s not dwell on the
positives.</p>
<p>This machine is equipped with four “cliff” sensors along its front edge, which
are designed to prevent it from driving right down a flight of stairs or off
of… Some other <em>totally normal</em> precipitous residential ledge.</p>
<p>It’s probably just for stairs.</p>
<p>Anyway, these sensors appear to be your bog standard infrared reflectivity sensors,
which consist of an infrared LED and an infrared light sensor. Basically it’s a
remote control and the part on your TV that “sees” the remote’s light beam, but
placed next to each other so that the beam has to bounce off the floor to return
to the “eye.”</p>
<p>This is a good choice of component because the parts are cheap and they’re easy
to use. The way it operates, based on my observations, is that the Roomba is
continually firing off infrared pulses and watching for the returns. If the
pulses suddenly go away (or possibly get very faint), Roomba assumes that the
distance the beam traveled increased markedly, as it would if the edge of the
robot was hanging off the stairs.</p>
<p>Clever!</p>
<p>Also, stupid!</p>
<p>The reason this became a problem for me is that our dining room rug has a
dramatic pattern, with areas that are pure white alongside areas that are pure
black. You can probably see where this is going. When Roomba passes from a white
area to a black area, it affects the infrared light the same way an increase in
distance would, since white reflects most light and black absorbs most light.</p>
<p>the net result is that Roomba would <em>frequently</em> end up “trapped” between a
black shape on the rug and an actual chair leg, and, thinking that it had
nowhere it could go, would sound the infamous “error 6” and turn off.</p>
<p>The only thing worse than an automatic vacuum that requires constant human
intervention is the Chrysler PT Cruiser, which I remain absolutely <em>boggled</em>
that anyone ever bought, and yet I still see them on the road occasionally and
it takes all of my strength not to follow them until they park somewhere so I
can ask the owner what, honestly, in the name of all Earthly pursuits, they were
high on when they bought it.</p>
<p>I mean really, what is the point of having an automatic vacuum that requires
your continuous presence and attention? I want this thing to run at night while
I’m asleep, or when I’m not even here. I don’t want to get back hours later and
find that it did 12 minutes of work and got “trapped” on a <em>dangerous rug color</em>.</p>
<p>Being the industrious tinkerer that I am, I certainly wasn’t going to let a
little infrared beam stop me from building an <em>army of robot servants</em> so that I
can sit back and fully enjoy the toil and anxiety of my actual day job without
the distraction of trivial household chores.</p>
<p>At first, I figured I could just tape over the sensors. I concluded that the
robot needs to <em>see</em> the reflection to know that the floor is <em>there,</em> so I even
used aluminum tape for maximum reflectiveness. The robot refused to turn on,
complaining that it needed to be moved every time. I took a closer look.</p>
<p></p><p>The sensors are divided in two halves, one containing the emitter and the other
containing the detector. Sensibly, and obviously in retrospect, the two halves
are separated by an opaque wall so that the detector is certain to receive <em>only
reflections</em> rather than any direct “spill” from the emitter. Taping over it
stopped <em>all of the light</em> from reaching the detector.</p>
<p>Hmm. So what I need is a way to get the light from the emitter to go around the
divider and into the detector, fooling Roomba into thinking there is floor under
it at all times.</p>
<p>It is at this point that I will note that our house has no cliffs. There is a
stairway to the basement that has a door with spring hinges that is therefore
always closed, so there is no chance Roomba can drive off of anything here.</p>
<p>My second attempt was to use paper. I love a little quick and dirty prototyping
with some card stock and tape. I cut out a couple of squares, folded them to go
around the sensor housings, and used painter’s tape to secure it such that a
gap was maintained between the housing and the paper so the beam could bounce.</p>
<p></p><p>I placed the Roomba on the white area of the rug, facing the black area, and
turned it on. It worked! It turned on and started rolling forward, stopping when
one of the <em>side sensors</em> reached the black edge! I quickly prepared two more
paper covers.</p>
<p>With the paper in place, Roomba happily drove all around the troublesome rug
with no issues.</p>
<p>I left it this way for a couple of days. But something about paper… It just
doesn’t satisfy. Not when you have a Prusa i3 MK2 3D printer and an abiding love
for Autocad Fusion 360. I got to work.</p>
<p></p><p>Pictured above is something like version three. I took a picture of the sensor
with my phone and imported it into Fusion 360 to trace the curve, and I used my
calipers to get accurate major dimensions. Surprisingly, it fit the first time,
but I refined it a bit and it isn’t worth showing all the changes here.</p>
<p>The cap slides right over the sensor and because the sensor is angled and the
cap is not, there is sufficient gap for the light beam to get from the emitter
side to the detector side. Viola! Here is what it looks like in real life:</p>
<p></p><p>And installed:</p>
<p></p><h2>Victory!</h2>
<p>Yes, well, almost. The “blinders,” as I’ve taken to calling them, work perfectly
to keep Roomba darting around across my problematic rug, so now it only gets
stuck very occasionally when it actually jams itself in some weird spot, though
so far that has happened very rarely.</p>
<p>There are two things I didn’t account for. First, there is a spinning brush on
one side that is supposed to push dirt and crumbs out from the wall so the
Roomba can suck them up and the brush was hitting the blinder cap, making an
awful noise.</p>
<p>I solved that by making a special cap for that one sensor that incorporates a
curved profile on the brush side so that it only barely touches it as it passes
over, and that did the trick.</p>
<p></p><p>Second, on the first real time out with all the blinder caps installed, Roomba
got stuck on the rug and commanded me to move it. I was filled with seething
rage until I realized that one of them had fallen off.</p>
<p>Duct tape to the rescue.</p>
<h2>Actual victory!</h2>
<p>So far, this is working. Should a consumer be required to engage in some light
industrial design and fabrication to make this product work on a patterned
surface? I should say not.</p>
<p>It was still fun, though.</p>
 </div>||||I||||The Chronicle

of a ColdFusion Expatriate

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 The Chronicle

 Blinding My Roomba

 April 23, 2021

 I got a Roomba, which is pretty neat, but it’s also pretty stupid. As it turns out, it works better for me if it’s crippled and I’m going to tell you how I did it. And why; I’ll also tell you why.

 This is a story about an iRobotÂ® RoombaÂ® 675 Wi-FiÂ® Connected Robot Vacuum, an array of infrared “cliff” sensors, and a man who is fed up with their bullshit.

 I purchased a Roomba because my wife has been begging for one for years, but until now I couldn’t justify the price. At this point, there are so many robot vacuums on the market you can find one to suit whatever your needs or budget may be, but rather than spending time discovering available features and considering my needs and wants, I just bought The Wirecutter’s top-rated model, which is the iRobot Roomba 675.

 The Wirecutter advises that you can likely get by with the 614, which doesn’t have Wi-Fi, but I wanted to be able to schedule when it will do its thing, so I paid a bit more. As I write this, Amazon is selling the 675 for the same price as the 614, so watch for those sales!

 Long story short, the Roomba actually works better than I thought it would. It picks up a lot of crumbs and dirt, and I can tell from just looking at our living room rug whether it’s been around or not. But let’s not dwell on the positives.

 This machine is equipped with four “cliff” sensors along its front edge, which are designed to prevent it from driving right down a flight of stairs or off of… Some other totally normal precipitous residential ledge.

 It’s probably just for stairs.

 Anyway, these sensors appear to be your bog standard infrared reflectivity sensors, which consist of an infrared LED and an infrared light sensor. Basically it’s a remote control and the part on your TV that “sees” the remote’s light beam, but placed next to each other so that the beam has to bounce off the floor to return to the “eye.”

 This is a good choice of component because the parts are cheap and they’re easy to use. The way it operates, based on my observations, is that the Roomba is continually firing off infrared pulses and watching for the returns. If the pulses suddenly go away (or possibly get very faint), Roomba assumes that the distance the beam traveled increased markedly, as it would if the edge of the robot was hanging off the stairs.

 Clever!

 Also, stupid!

 The reason this became a problem for me is that our dining room rug has a dramatic pattern, with areas that are pure white alongside areas that are pure black. You can probably see where this is going. When Roomba passes from a white area to a black area, it affects the infrared light the same way an increase in distance would, since white reflects most light and black absorbs most light.

 the net result is that Roomba would frequently end up “trapped” between a black shape on the rug and an actual chair leg, and, thinking that it had nowhere it could go, would sound the infamous “error 6” and turn off.

 The only thing worse than an automatic vacuum that requires constant human intervention is the Chrysler PT Cruiser, which I remain absolutely boggled that anyone ever bought, and yet I still see them on the road occasionally and it takes all of my strength not to follow them until they park somewhere so I can ask the owner what, honestly, in the name of all Earthly pursuits, they were high on when they bought it.

 I mean really, what is the point of having an automatic vacuum that requires your continuous presence and attention? I want this thing to run at night while I’m asleep, or when I’m not even here. I don’t want to get back hours later and find that it did 12 minutes of work and got “trapped” on a dangerous rug color.

 Being the industrious tinkerer that I am, I certainly wasn’t going to let a little infrared beam stop me from building an army of robot servants so that I can sit back and fully enjoy the toil and anxiety of my actual day job without the distraction of trivial household chores.

 At first, I figured I could just tape over the sensors. I concluded that the robot needs to see the reflection to know that the floor is there, so I even used aluminum tape for maximum reflectiveness. The robot refused to turn on, complaining that it needed to be moved every time. I took a closer look.

 The sensors are divided in two halves, one containing the emitter and the other containing the detector. Sensibly, and obviously in retrospect, the two halves are separated by an opaque wall so that the detector is certain to receive only reflections rather than any direct “spill” from the emitter. Taping over it stopped all of the light from reaching the detector.

 Hmm. So what I need is a way to get the light from the emitter to go around the divider and into the detector, fooling Roomba into thinking there is floor under it at all times.

 It is at this point that I will note that our house has no cliffs. There is a stairway to the basement that has a door with spring hinges that is therefore always closed, so there is no chance Roomba can drive off of anything here.

 My second attempt was to use paper. I love a little quick and dirty prototyping with some card stock and tape. I cut out a couple of squares, folded them to go around the sensor housings, and used painter’s tape to secure it such that a gap was maintained between the housing and the paper so the beam could bounce.

 I placed the Roomba on the white area of the rug, facing the black area, and turned it on. It worked! It turned on and started rolling forward, stopping when one of the side sensors reached the black edge! I quickly prepared two more paper covers.

 With the paper in place, Roomba happily drove all around the troublesome rug with no issues.

 I left it this way for a couple of days. But something about paper… It just doesn’t satisfy. Not when you have a Prusa i3 MK2 3D printer and an abiding love for Autocad Fusion 360. I got to work.

 Pictured above is something like version three. I took a picture of the sensor with my phone and imported it into Fusion 360 to trace the curve, and I used my calipers to get accurate major dimensions. Surprisingly, it fit the first time, but I refined it a bit and it isn’t worth showing all the changes here.

 The cap slides right over the sensor and because the sensor is angled and the cap is not, there is sufficient gap for the light beam to get from the emitter side to the detector side. Viola! Here is what it looks like in real life:

 And installed:

 Victory!

 Yes, well, almost. The “blinders,” as I’ve taken to calling them, work perfectly to keep Roomba darting around across my problematic rug, so now it only gets stuck very occasionally when it actually jams itself in some weird spot, though so far that has happened very rarely.

 There are two things I didn’t account for. First, there is a spinning brush on one side that is supposed to push dirt and crumbs out from the wall so the Roomba can suck them up and the brush was hitting the blinder cap, making an awful noise.

 I solved that by making a special cap for that one sensor that incorporates a curved profile on the brush side so that it only barely touches it as it passes over, and that did the trick.

 Second, on the first real time out with all the blinder caps installed, Roomba got stuck on the rug and commanded me to move it. I was filled with seething rage until I realized that one of them had fallen off.

 Duct tape to the rescue.

 Actual victory!

 So far, this is working. Should a consumer be required to engage in some light industrial design and fabrication to make this product work on a patterned surface? I should say not.

 It was still fun, though.

 Posted by Aaron Bieber Apr 23, 2021

 « Arduino Swivel Lamp Can Remote Work... Work? »

 Comments

 Hi, I'm Aaron Bieber. Once, long ago, I wrote ColdFusion for a living. Now I coach engineering leaders and write about tech and social topics on this blog.

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I got a Roomba, which is pretty neat, but it’s also pretty stupid. As it turns
out, it works better for me if it’s crippled and I’m going to tell you how I did
it. And why; I’ll also tell you why.
This is a story about an iRobotÂ® RoombaÂ® 675 Wi-FiÂ® Connected Robot Vacuum, an
array of infrared “cliff” sensors, and a man who is fed up with their bullshit.
I purchased a Roomba because my wife has been begging for one for years, but
until now I couldn’t justify the price. At this point, there are so many robot
vacuums on the market you can find one to suit whatever your needs or budget may
be, but rather than spending time discovering available features and considering
my needs and wants, I just bought The Wirecutter’s top-rated model, which is the
iRobot Roomba 675.
The Wirecutter advises that you can likely get by with the 614, which doesn’t
have Wi-Fi, but I wanted to be able to schedule when it will do its thing, so I
paid a bit more. As I write this, Amazon is selling the 675 for the same price
as the 614, so watch for those sales!
Long story short, the Roomba actually works better than I thought it would. It
picks up a lot of crumbs and dirt, and I can tell from just looking at our
living room rug whether it’s been around or not. But let’s not dwell on the
positives.
This machine is equipped with four “cliff” sensors along its front edge, which
are designed to prevent it from driving right down a flight of stairs or off
of… Some other totally normal precipitous residential ledge.
It’s probably just for stairs.
Anyway, these sensors appear to be your bog standard infrared reflectivity sensors,
which consist of an infrared LED and an infrared light sensor. Basically it’s a
remote control and the part on your TV that “sees” the remote’s light beam, but
placed next to each other so that the beam has to bounce off the floor to return
to the “eye.”
This is a good choice of component because the parts are cheap and they’re easy
to use. The way it operates, based on my observations, is that the Roomba is
continually firing off infrared pulses and watching for the returns. If the
pulses suddenly go away (or possibly get very faint), Roomba assumes that the
distance the beam traveled increased markedly, as it would if the edge of the
robot was hanging off the stairs.
Clever!
Also, stupid!
The reason this became a problem for me is that our dining room rug has a
dramatic pattern, with areas that are pure white alongside areas that are pure
black. You can probably see where this is going. When Roomba passes from a white
area to a black area, it affects the infrared light the same way an increase in
distance would, since white reflects most light and black absorbs most light.
the net result is that Roomba would frequently end up “trapped” between a
black shape on the rug and an actual chair leg, and, thinking that it had
nowhere it could go, would sound the infamous “error 6” and turn off.
The only thing worse than an automatic vacuum that requires constant human
intervention is the Chrysler PT Cruiser, which I remain absolutely boggled
that anyone ever bought, and yet I still see them on the road occasionally and
it takes all of my strength not to follow them until they park somewhere so I
can ask the owner what, honestly, in the name of all Earthly pursuits, they were
high on when they bought it.
I mean really, what is the point of having an automatic vacuum that requires
your continuous presence and attention? I want this thing to run at night while
I’m asleep, or when I’m not even here. I don’t want to get back hours later and
find that it did 12 minutes of work and got “trapped” on a dangerous rug color.
Being the industrious tinkerer that I am, I certainly wasn’t going to let a
little infrared beam stop me from building an army of robot servants so that I
can sit back and fully enjoy the toil and anxiety of my actual day job without
the distraction of trivial household chores.
At first, I figured I could just tape over the sensors. I concluded that the
robot needs to see the reflection to know that the floor is there, so I even
used aluminum tape for maximum reflectiveness. The robot refused to turn on,
complaining that it needed to be moved every time. I took a closer look.
  The sensors are divided in two halves, one containing the emitter and the other
containing the detector. Sensibly, and obviously in retrospect, the two halves
are separated by an opaque wall so that the detector is certain to receive only
reflections rather than any direct “spill” from the emitter. Taping over it
stopped all of the light from reaching the detector.
Hmm. So what I need is a way to get the light from the emitter to go around the
divider and into the detector, fooling Roomba into thinking there is floor under
it at all times.
It is at this point that I will note that our house has no cliffs. There is a
stairway to the basement that has a door with spring hinges that is therefore
always closed, so there is no chance Roomba can drive off of anything here.
My second attempt was to use paper. I love a little quick and dirty prototyping
with some card stock and tape. I cut out a couple of squares, folded them to go
around the sensor housings, and used painter’s tape to secure it such that a
gap was maintained between the housing and the paper so the beam could bounce.
  I placed the Roomba on the white area of the rug, facing the black area, and
turned it on. It worked! It turned on and started rolling forward, stopping when
one of the side sensors reached the black edge! I quickly prepared two more
paper covers.
With the paper in place, Roomba happily drove all around the troublesome rug
with no issues.
I left it this way for a couple of days. But something about paper… It just
doesn’t satisfy. Not when you have a Prusa i3 MK2 3D printer and an abiding love
for Autocad Fusion 360. I got to work.
  Pictured above is something like version three. I took a picture of the sensor
with my phone and imported it into Fusion 360 to trace the curve, and I used my
calipers to get accurate major dimensions. Surprisingly, it fit the first time,
but I refined it a bit and it isn’t worth showing all the changes here.
The cap slides right over the sensor and because the sensor is angled and the
cap is not, there is sufficient gap for the light beam to get from the emitter
side to the detector side. Viola! Here is what it looks like in real life:
  And installed:
  Victory!
Yes, well, almost. The “blinders,” as I’ve taken to calling them, work perfectly
to keep Roomba darting around across my problematic rug, so now it only gets
stuck very occasionally when it actually jams itself in some weird spot, though
so far that has happened very rarely.
There are two things I didn’t account for. First, there is a spinning brush on
one side that is supposed to push dirt and crumbs out from the wall so the
Roomba can suck them up and the brush was hitting the blinder cap, making an
awful noise.
I solved that by making a special cap for that one sensor that incorporates a
curved profile on the brush side so that it only barely touches it as it passes
over, and that did the trick.
  Second, on the first real time out with all the blinder caps installed, Roomba
got stuck on the rug and commanded me to move it. I was filled with seething
rage until I realized that one of them had fallen off.
Duct tape to the rescue.
Actual victory!
So far, this is working. Should a consumer be required to engage in some light
industrial design and fabrication to make this product work on a patterned
surface? I should say not.
It was still fun, though.
Blinding My Roomba
https://blog.aaronbieber.com/2021/04/23/blinding-my-roomba.html?utm_source=bengtan.com
https://iwonteverbehappyagain.tumblr.com/tagged/Chris%20Regnault
Chris Regnault
2011-06-24
None
<div><div>
<article>
<div>
<header>
<a href="https://justinrampage.tumblr.com/post/6863993045/thedeathblowbisart"><i></i>justinrampage</a>
</header>
<section>
<figure>
<div>
<p><a href="https://iwonteverbehappyagain.tumblr.com/image/6865042794"></a>
</p>
</div>
<div>
<div>
<div>
<p><a href="https://iwonteverbehappyagain.tumblr.com/post/6865042794/thedeathblowbisart">
</a>
</p>
</div>
<p><a href="https://iwonteverbehappyagain.tumblr.com/post/6865042794/thedeathblowbisart">iwonteverbehappyagain</a>
</p></div>
<div>
<p><a href="http://rampagedreality.com/post/6863993045/thedeathblowbisart">justinrampage</a>:</p><blockquote><p>The fearless Link faces off against Ganon in an all out battle thanks to Chris Regnault and his excellent illustration skills. Check out more of his work <a href="http://bisart.deviantart.com/gallery/">HERE</a>.</p><p><strong>Related Rampage</strong>: <a href="http://rampagedreality.com/post/1151329471/intense-artwork-by-chris-regnault-link-has-fallen"><em>Link’s Trap</em></a></p><p><a href="http://bisart.deviantart.com/art/The-Deathblow-214702458"><em>The Deathblow</em></a> by <strong><a href="http://bisart.deviantart.com/">Chris Regnault</a></strong> / <strong><a href="http://bisart.deviantart.com/">Bisart</a></strong> (<strong><a href="http://biszarbook.blogspot.com/">Blog</a></strong>)</p></blockquote>
</div>
</div>
</figure>
<section>
<a href="https://iwonteverbehappyagain.tumblr.com/tagged/Zelda">Zelda</a>
<a href="https://iwonteverbehappyagain.tumblr.com/tagged/Gaming">Gaming</a>
<a href="https://iwonteverbehappyagain.tumblr.com/tagged/Link">Link</a>
<a href="https://iwonteverbehappyagain.tumblr.com/tagged/Ganon">Ganon</a>
<a href="https://iwonteverbehappyagain.tumblr.com/tagged/Art">Art</a>
<a href="https://iwonteverbehappyagain.tumblr.com/tagged/Illustration">Illustration</a>
<a href="https://iwonteverbehappyagain.tumblr.com/tagged/Design">Design</a>
<a href="https://iwonteverbehappyagain.tumblr.com/tagged/Chris%20Regnault">Chris Regnault</a>
<a href="https://iwonteverbehappyagain.tumblr.com/tagged/Bisart">Bisart</a>
</section>
</section>
</div>
</article>
</div></div>||||I|||| 1.5M ratings
 277k ratings

 See, that’s what the app is perfect for.

 Sounds perfect Wahhhh, I don’t wanna

 This is the first day of my life

 I'm a nerd.

 Instagram: Rey_Joestar
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 justinrampage

 iwonteverbehappyagain

 justinrampage:

 The fearless Link faces off against Ganon in an all out battle thanks to Chris Regnault and his excellent illustration skills. Check out more of his work HERE.

 Related Rampage: Link’s Trap

 The Deathblow by Chris Regnault / Bisart (Blog)

 Zelda Gaming Link Ganon Art Illustration Design Chris Regnault Bisart
 277 notes Jun 24th, 2011
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justinrampage
  
 
 iwonteverbehappyagain
 
 justinrampage:  The fearless Link faces off against Ganon in an all out battle thanks to Chris Regnault and his excellent illustration skills. Check out more of his work HERE.  Related Rampage:  Link’s Trap     The Deathblow  by  Chris Regnault  /  Bisart  ( Blog ) 
Zelda
Gaming
Link
Ganon
Art
Illustration
Design
Chris Regnault
Bisart
Chris Regnault
https://iwonteverbehappyagain.tumblr.com/tagged/Chris%20Regnault
https://blog.shannoneichorn.com/?p=192
What I Wish People Knew About Engineers
2015-10-26
Shannon
<div><section>
	<main>
	<div>
	
<div>
	<article>
	<div>
	<p>Coming up, I’m starting a new, six-part series about what I wish people knew about engineers. This is inspired by assumptions I’ve encountered at conventions, committees, church, and anywhere else I’ve spent time interacting with non-engineers; there are a plethora of times I’d love to sit people down to a nice half-hour conversation on why I can’t just pull a solution or assessment out of thin air or meet the newest expectations.</p>
<p>I want to start off by saying that everyone’s experiences are different–and I’d love to hear your comparison and thoughts in comments. This is my list of slowly-accruing pet peeves, and while it’s imperfect, I’m hope it will help non-engineers understand us a little better.</p>
<p>What I wish people knew about engineers:</p>
<ol>
<li>We can be distinct from scientists.</li>
<li>We are not omniscient.</li>
<li>We are invisibly vital to society.</li>
<li>We have social skills, and we party, too! (Most of us.)</li>
<li>We are not necessarily math whizzes.</li>
<li>Math is a language–and it has dialects we don’t all speak.</li>
</ol>
<p>Coming up first (soon after my lab coat arrives): the difference between engineers and scientists.</p>
	</div>
	</article>
</div>
	
<div>
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	<p>
	Shannon Eichorn is a scifi writer and aerospace engineer. She lives in the Cleveland area with her domesticated mad rocket scientist and can be followed at @ShannonEichorn on Twitter, AuthorShannonEichorn on Facebook, and www.shannoneichorn.com.	<a href="https://blog.shannoneichorn.com/?author=1">
	View all posts by Shannon	</a>
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 What I Wish People Knew About Engineers

 by Shannon Posted on October 26, 2015February 2, 2020

 Coming up, I’m starting a new, six-part series about what I wish people knew about engineers. This is inspired by assumptions I’ve encountered at conventions, committees, church, and anywhere else I’ve spent time interacting with non-engineers; there are a plethora of times I’d love to sit people down to a nice half-hour conversation on why I can’t just pull a solution or assessment out of thin air or meet the newest expectations.

 I want to start off by saying that everyone’s experiences are different–and I’d love to hear your comparison and thoughts in comments. This is my list of slowly-accruing pet peeves, and while it’s imperfect, I’m hope it will help non-engineers understand us a little better.

 What I wish people knew about engineers:

 1. We can be distinct from scientists.
 2. We are not omniscient.
 3. We are invisibly vital to society.
 4. We have social skills, and we party, too! (Most of us.)
 5. We are not necessarily math whizzes.
 6. Math is a language–and it has dialects we don’t all speak.

 Coming up first (soon after my lab coat arrives): the difference between engineers and scientists.

 Posted in Engineering , Language , Life , Math , Science , Technology

 Published by Shannon

 Shannon Eichorn is a scifi writer and aerospace engineer. She lives in the Cleveland area with her domesticated mad rocket scientist and can be followed at @ShannonEichorn on Twitter, AuthorShannonEichorn on Facebook, and www.shannoneichorn.com. View all posts by Shannon

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Coming up, I’m starting a new, six-part series about what I wish people knew about engineers. This is inspired by assumptions I’ve encountered at conventions, committees, church, and anywhere else I’ve spent time interacting with non-engineers; there are a plethora of times I’d love to sit people down to a nice half-hour conversation on why I can’t just pull a solution or assessment out of thin air or meet the newest expectations.
I want to start off by saying that everyone’s experiences are different–and I’d love to hear your comparison and thoughts in comments. This is my list of slowly-accruing pet peeves, and while it’s imperfect, I’m hope it will help non-engineers understand us a little better.
What I wish people knew about engineers:
We can be distinct from scientists.
We are not omniscient.
We are invisibly vital to society.
We have social skills, and we party, too! (Most of us.)
We are not necessarily math whizzes.
Math is a language–and it has dialects we don’t all speak.
Coming up first (soon after my lab coat arrives): the difference between engineers and scientists.
	
	
	
		
	
	Shannon Eichorn is a scifi writer and aerospace engineer. She lives in the Cleveland area with her domesticated mad rocket scientist and can be followed at @ShannonEichorn on Twitter, AuthorShannonEichorn on Facebook, and www.shannoneichorn.com.	
	View all posts by Shannon
What I Wish People Knew About Engineers
https://blog.shannoneichorn.com/?p=192
https://engineering.tapad.com/technical-writing-for-non-technical-people-9046aa65346e?gi=ea2bd4044ddc
Technical Writing for Non-Technical People - Tapad Engineering
2020-03-06T18:16:55Z
Keri Savoca
<html><body><div><div><div><h2>A few tricks to help you tackle that documentation backlog</h2><div><a href="https://kerisavoca.medium.com/?source=post_page-----9046aa65346e--------------------------------"><div><p></p></div></a><a href="https://engineering.tapad.com/?source=post_page-----9046aa65346e--------------------------------"><div><p></p></div></a></div></div><p><strong>I made the title vague on purpose. </strong>Are you writing <em>for</em> non-technical people? Or are <em>you</em> a non-technical person who needs to write technical things?</p><p>It actually doesn’t matter.</p><p>Some companies have a whole team of technical writers. Others have one or two. Some have no technical writers at all, and they assign documentation-related tasks to anyone who is willing to tackle them. This person could be you!</p><p>Not feeling 100% confident? Here are a few tricks that will help you tackle your documentation-related backlog in no time.</p><h2>Technical writing doesn’t have to be boring.</h2><p>If it’s boring for you to write, it will probably be boring for others to read. This is especially true for internal documentation. You really don’t need to be so rigid, as long as you are clear and precise. It’s best to leave nothing up for interpretation — but this doesn’t mean your writing can’t have a voice.</p><h2>Speak to your actual audience.</h2><p>These aren’t your personal notes, so be cognizant of that. But it’s not your dissertation, either. Nobody is handing out prizes for the most extravagant documentation.</p><p>Your goal is to take complex information and make it easy to understand. That’s it.</p><p>This is why “explain like I’m 5” is my mantra. If you can use a simpler word, or if you can explain something in a more relatable way, just do it. Don’t make people crack open a dictionary in order to make sense of your documentation.</p><h2>Design, formatting, and organization are important.</h2><p>Remember: you’re trying to make things <em>easier</em> for people to figure out.</p><ul><li>Documents should have predictable titles. No weird abbreviations, no <code>untitled-v2-final_FINAL</code>, no <code>doc1-revision.docx.pdf</code>, etc.</li><li>Screenshots (if used) should be purposeful, clear, and labeled.</li><li>Use headers, sub-headers, and body text strategically. Tables of contents don’t create themselves unless you use headers! 😉</li></ul></div></div></body></html>
A few tricks to help you tackle that documentation backlog                 I made the title vague on purpose. Are you writing for non-technical people? Or are you a non-technical person who needs to write technical things? It actually doesn’t matter. Some companies have a whole team of technical writers. Others have one or two. Some have no technical writers at all, and they assign documentation-related tasks to anyone who is willing to tackle them. This person could be you! Not feeling 100% confident? Here are a few tricks that will help you tackle your documentation-related backlog in no time. Technical writing doesn’t have to be boring. If it’s boring for you to write, it will probably be boring for others to read. This is especially true for internal documentation. You really don’t need to be so rigid, as long as you are clear and precise. It’s best to leave nothing up for interpretation — but this doesn’t mean your writing can’t have a voice. Speak to your actual audience. These aren’t your personal notes, so be cognizant of that. But it’s not your dissertation, either. Nobody is handing out prizes for the most extravagant documentation. Your goal is to take complex information and make it easy to understand. That’s it. This is why “explain like I’m 5” is my mantra. If you can use a simpler word, or if you can explain something in a more relatable way, just do it. Don’t make people crack open a dictionary in order to make sense of your documentation. Design, formatting, and organization are important. Remember: you’re trying to make things easier for people to figure out.  Documents should have predictable titles. No weird abbreviations, no untitled-v2-final_FINAL, no doc1-revision.docx.pdf, etc. Screenshots (if used) should be purposeful, clear, and labeled. Use headers, sub-headers, and body text strategically. Tables of contents don’t create themselves unless you use headers! 😉
Technical Writing for Non-Technical People - Tapad Engineering
https://engineering.tapad.com/technical-writing-for-non-technical-people-9046aa65346e