user7740: I am making a robot with arduino mega r3. I want to power the arduino with a usb power bank. How should I do that?

user28194: Powerbank is a term for those external batteries that output USB. Usually used to recharge a phone when you don't have access to wall outlet and USB charger.
Inside powerbank:
Battery (3.7v) --- Some Circuit --- USB female
How to: 
You have a bank
You have USB cable
ugh! ...
Plug USB to Arduino and you are (pretty much) done.
For those who use ProMini and/or want to skip the USB port
Cut the USB cable and take the red (+) and black (-).
Put it directly to Vin and Gnd and you are good to go.
*
Unfortunately for us (fortunately for most) most Powerbank has auto-shutoff where it will shut off the power if there's no load (usually ~50mA, vary with every brand). Since Arduino may not draw that much, the battery thinks it is not connected to anything.. thus it will auto-shutoff after a while
I found this trick helps (a lot!! thank you!):
https://www.dorkbotpdx.org/blog/paul/battery_pack_load


user6740: I have a "USB power bank" with two USB ports, which I use to power some projects.
I have discovered that my bank (i.e. your mileage may vary!) shuts off unless my project draws at least 50mA. If your project does draw at least that at ALL times, you should just be able to plug a USB cable directly from the powerbank to the project.
For some other projects, I have bought a USB cable (USB A to USB A) which I cut in half, stripped the wires, then used a multimeter set to "Volts" to work out which wire was +5V and which was GND; I connect these straight to the 5V/GND on my project. To make sure at least 50mA was drawn at all times, I put a 100 Ohm resistor from +5V to GND (at LEAST 1/4 watt!!). This obviously wastes a lot of power (turning it into 1/4 watt of heat), but it keeps the power bank "awake". By using a USB A to USB A, I now have two cables.
My power bank also has a "torch" (led) integrated; if the torch is on, it also stays awake.

7740: <p><strong>I am making a robot with arduino mega r3. I want to power the arduino with a usb power bank. How should I do that?</strong></p>
 28194: <p>Powerbank is a term for those external batteries that output USB. Usually used to recharge a phone when you don't have access to wall outlet and USB charger.</p>

<p>Inside powerbank:<br>
Battery (3.7v) --- Some Circuit --- USB female</p>

<p>How to: <br>
You have a bank<br>
You have USB cable<br>
ugh! ...<br>
Plug USB to Arduino and you are (pretty much) done.</p>

<p>For those who use ProMini and/or want to skip the USB port<br>
Cut the USB cable and take the red (+) and black (-).</p>

<p>Put it directly to Vin and Gnd and you are good to go.</p>

<p>*</p>

<p>Unfortunately for us (fortunately for most) most Powerbank has auto-shutoff where it will shut off the power if there's no load (usually ~50mA, vary with every brand). Since Arduino may not draw that much, the battery thinks it is not connected to anything.. thus it will auto-shutoff after a while</p>

<p>I found this trick helps (a lot!! thank you!):<br>
<a href="https://www.dorkbotpdx.org/blog/paul/battery_pack_load" rel="nofollow noreferrer">https://www.dorkbotpdx.org/blog/paul/battery_pack_load</a></p>

<p><a href="https://i.stack.imgur.com/klnNx.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/klnNx.jpg" alt=""></a></p>
 6740: <p>I have a "USB power bank" with two USB ports, which I use to power some projects.</p>

<p>I have discovered that my bank (i.e. your mileage may vary!) shuts off unless my project draws at least 50mA. If your project does draw at least that at ALL times, you should just be able to plug a USB cable directly from the powerbank to the project.</p>

<p>For some other projects, I have bought a USB cable (USB A to USB A) which I cut in half, stripped the wires, then used a multimeter set to "Volts" to work out which wire was +5V and which was GND; I connect these straight to the 5V/GND on my project. To make sure at least 50mA was drawn at all times, I put a 100 Ohm resistor from +5V to GND (at LEAST 1/4 watt!!). This obviously wastes a lot of power (turning it into 1/4 watt of heat), but it keeps the power bank "awake". By using a USB A to USB A, I now have two cables.</p>

<p>My power bank also has a "torch" (led) integrated; if the torch is on, it also stays awake.</p>
