Move Over, Google Nest: Open Source Thermostat Is Heating Up the Internet of Things

In the wake of Google’s purchase of connected devices interest Nest, the gents at [Spark] set about to making one in roughly a day and for a fraction of the cost it took Nest to build their initial offering. [Spark]‘s aim is to put connected devices within reach of the average consumer, and The Next Big Thing within the reach of the average entrepreneur.

The brain is, of course, [Spark]‘s own Spark Core wi-fi dev board. The display is made of three adafruit 8×8 LED matrices driven over I²C. Also on the bus is a combination temperature and humidity sensor, the Honeywell HumidIcon. They added some status LEDs for the furnace and the fan, and a Panasonic PIR motion detector to judge whether you are home. The attractive enclosure is made of two CNC-milled wood rings. The face plate, mounting plate, and connection from the twistable wood ring to the potentiometer is laser-cut acrylic.

[Spark]‘s intent is for this, like the Nest, to be a learning thermostat for the purpose of increasing energy efficiency over time, so they’ve built a web interface with a very simple UI. The interface also displays historical data, which is always nice. This project is entirely open source and totally awesome.

If you have an old Android phone lying around, you could make this open source Android thermostat.

[Thanks, Zach]


  1. Rasputin says:

    Will it have Nest’s security failures and fanboy-markup price tag?

  2. ASte4 says:

    It’s like the nest, except lacking aesthetic design…one of the major features that make the nest, the nest and not just another thermostat.

    • Reggie says:

      so wait, the nests best feature is that it looks good? We’re doomed as a species…..

      • ASte4 says:

        Try reading my post, I didn’t say best, I said one of the major features. That is a selling point of that particular brand and device.

      • static says:

        For an item that’s going to be in predominate view all the time, appearance is a feature that will rank high in it’s success. Personally I think it’s as ugly as wall wart power supply; no disrespect to the builder intended. In the event I where to participate in the open source community for this, I would design a model, that could fit into a 2 gang electrical device box, with display and controls that are as flush with the wall surface as possible.

        Chances are someone dissatisfied with the appearance of something they own, and set out to change the appearance to what they like , with projects like this they simply package differently when they wrap up the build. Those are hacks in themselves, most likely are the largest group of hacks being made. So common place they may not deserve to be featured at Hackaday unless the the result is extraordinary or the hacker’s write up teaches a skill or process that would benefit other DIY individuals. BTW prehistoric at or all the other art created since hasn’t doomed our species as of yet. Although if I where to place reproductions classic statues of nude persons in my front yard a local conflict would be created. Unfortunately I can afford to do that :)

        • mh says:

          I too think the pictured device is an eyesore. But beauty is in the eye of the beholder, it is what is inside that counts :-)

          Most people would just buy a different product if they do not like what they see. Those who would buy a product (where alternatives exists) and then put it in a new enclosure may be common on HAD, in the real world, not so much.

    • Colin says:

      “It’s like the nest, except lacking aesthetic design…” and a voltage regulator…and relays.

      So: It’s like the nest, except lacking the things to actually make it a thermostat.

    • Anonymous says:

      Just build yours in the case from an old Honeywell T87!

    • Luke says:

      Ehh, the silver-and-black look of the Nest is sexier, but this is certainly better looking than a typical programmable thermostat.

      At least it’s round, simple, and appropriately sized, not unlike Henry Dreyfuss’ original design. The wood-and-frosted-plastic look is nice. Definitely reminds me of a Monome.

  3. fartface says:

    Honestly, a thermostat is a simple device, anyone can build one with an arduino. At least for low end of very old furnaces that use a simple contact closure. Most better new ones use a special rs485 or other communication to the thermostat and the NEST doesnt work on those either.

    It’s a race for obsolete as new high efficiency furnaces and AC do not work with them.

  4. Reggie says:

    Anyone know how you regulate heat properly on a storage heater?

    • static says:

      Not that I’m an expert on it, one regulates in the same way we regulate space heating. When the temperature rises to certain point you stop inputting heat, and when it cools you resume adding heat. In the event your storage medium can’t absorb all the heat being generate, one adds additional storage capabilities.

  5. Biomed says:

    Design your own likely = “You’ll shoot yer eye out kid!”. Very ripe for a home hacker FAIL! Better be sure you know how to drive relays reliably, prevent contact welding, and control the 18 to 28 VAC for old systems…. and Lord help ya on the newer stuff! You need to know and understand things like “watchdog timer/reset” and “battery life monitor”. This is not an area for a “learning project”. It all CAN BE DONE…. it can indeed be done… and I would trust folks like this group that seem to have the knowin’ and buy their thing… but making yer own is a whole different thing!

    Ya’all be careful out there. Weren’t NOT all in this together! Yer on yer own!

    • static says:

      But isn’t contact welding more of issue when switching DC that it is with AC? Since your one of those not interest in assisting others as you post your warnings, I guess I have to to look into it myself to see if I stand corrected. I know using the common household light switch shouldn’t be used with DC because of the contact welding issue. Part of my job in the oilfield was repairing motor controls. I can’t recall changing out a rely because of contact welding. Unless the relay was totally destroyed by lighting I kept the to scavenge the contacts for use in Morse code key constriction experiments so I would have known if welfed contact was the cause of failur Yes the contacts that switch the power to the motor where often replaced because arcing damage made them unreliable, but on some cases they would switch motor a hundred times a day at currents of 60 amps or more at 440 Volts. Depending on who constructed the control box the relays operated from 120 VAC with the contacts switching 120 Volts at low current and do that for years before needing service. Who knows how many electric heaters are operating at this moment with the thermostat point directly switching 120 VAC at up while operating off a 15 Amp AC circuit? I can’t tecall ant PSA concerning contact welding as an issue.

  6. Dustin says:

    Also of mention here, using a Non-commercially branded thermostat to control your furnace can void the warranty for your equipment. I know this is Hackaday, so voided warranty is typically the norm. It does seem a bit odd though with how simple most thermostat operate. I guess if you kill your furnace, you could quickly replace your home made thermostat for a commercial one and just tell them you have no idea why it died.

    • static says:

      Not to mention voiding insurance as well if a fire damages or destroys the house by fire no matter the cause. Insurance companies look for any reason to deny paying. Don’t think about removing it after the public fire inspector/ Marshall leaves. Getting caught tampering with evidence wouldn’t be good if a civil lawsuit takes place. Not saying that’s right but, it’s my conclusion from personal, experience first hand conversation with another, and serving as a juror in civil case involving a house fire.

  7. The Nest is cool, but the Webee is what I’ll be investing in. Not as invasive, and definitely better A.I.

  8. Andrew says:

    I would not have used a potentiometer for the user input. I would have used a quadrature encoder. With a potentiometer you have a certain value attached to a physical position of the pot, and you have physical end stops. With a quadrature encoder the value is disconnected from the physical position (and the input can rotate indefinitely).

    The reason for this is to decouple the thermostat set point from the position of the input knob. This allows the set point to be controlled remotely over the network and reported on the display, and allows the user to control the set point locally.

    Imagine you turned the pot all the way down, then you logged in remotely from your phone and turned the set point up. Now you come home and want to turn it down again- there is no further ‘down’ movement possible on the pot, so you’d have to use the phone (or your PC) or have some other input to say that the pot should override the network set point again. Maybe that’s the point of the PIR.

    An alternative is to have a motorised pot, so that local movement will change the set point, and remote adjustment will physically move the pot to reflect the new setting. I didn’t RTFA so I don’t know if this was done.

  9. cbob says:

    but can it send spam?

  10. vonskippy says:

    wow, I don’t think even the average consumer is into fugly, no matter how cheap it is. The nest was a ridiculously over priced gimmick for the people with more money then brains, but it did indeed look nice.

  11. RandomGuy says:

    This is cool. I’ve been having the same functionality in my house for years with a Proliphix thermostat which has an embedded web server and can be externally controlled. I get occupancy data from my alarm system’s motion sensors via an AD2USB board which feeds into the home automation system. I even display the outside temperature on the thermostat’s display via a web call, which I read from an external sensor using DHT22s connected to a RaspPI.

  12. uc says:

    This is a good marketing hack. 3.5 engineers worked 17 hours straight on this giving roughly 8 man days. They pushed all the functions to a Web backend that doesn’t really do anything.

    Nice use of cnc machining on the enclosure, I do like the physical method they used to make the basic rotary encoder hardware. I do think they made a nice looking device, more marketing than function at the moment.

  13. arnonymous says:

    I once built an arduino based thermostat.
    Recently i moved and now I have a honeywell wireless system. Does anyone know how i could use the arduino to broadcast the required signal, without replacing the standard receiver
    I couldnt find any similar projects.

  14. HelloKitty says:

    What a awful website with the video

  15. vreinel says:

    All this over a thermostat? If my wife is cold, it’s turned to the left until it hits the stops and if she is warm its all the way to the right no matter what the outside temp is. And if she does not know how to override the program, a hair dryer works well. I live in Florida, heat is used once or twice in winter and in the summer, pick a number everyone likes and walk away.
    A word about contactors. Most A/C systems in Florida come with a single pole contactor in the compressor unit. They either weld or the fire ants nest in them and they become insulators. A double contactor will reduce the problem but not eliminate it.

Leave a Reply


You are commenting using your account. Log Out / Change )

Twitter picture


Facebook photo


Google+ photo


Connecting to %s


Get every new post delivered to your Inbox.

Join 91,933 other followers