i have read different statements on this topic so wanted to start a focused discussion here. I want to use two small nano everys in my setup. One will only be there to decode some IR signals from a remote and turn on corresponding pins on board 1 and the other board will be running LED animations (but only having max 3 leds from a WS2812 strip on at a time).
Question is now. Can i power both boards from one USB power bank?
Can i somehow wire both arduinos together so the first one shares its power to the second or should i get a power bank which has two usb outs and would allow to power both individually?
Consider using just 1 Nano it should be more than capable of doing what you want. I cannot answer two from one power bank as I do not know what its capabilities are. Posting that information will help us help you. To select the power bank determine what your total load is and how long it needs to operate before recharging. Then choose a bank capable of meeting those requirements at a minimum. You can power both from the same power bank USB would work also direct wiring. Remember an arduino a power supply it is not!
thank you @gilshultz unfortunately my project involves the fastled library which excludes interrupts so i am not able to get clean readings from my IR receiver. I have already seen a lot of posts of other people struggling with the same problem and switching to a teensy as a solution but i wanted to give it a try with 2 boards.
Could you give me a bit more detail how i should be wiring up the two arduinos so they can share power?
I typically use several on the same power supply. I prefer Vin for a lot of reasons such as reverse battery protection and the extra filtering. I have cables with the mating plugs on or you can purchase them for not much money. If your power bank gives a clean regulated 5V you can connect that to each of the 5V pins, be sure all the grounds are connected. More information on the power bank would help.
Thank you @gilshultz and sorry for not replying quicker. I dont have the power bank yet and was wondering if it would make sense to buy one based on some specifics.
You need to have a basic idea of what you need. Two critical factors is how much current and at what voltage you need. Your unit has to supply that, then multiplying the current times the time you want it to operate will give you the capacity needed for the batteries. I multiply that number by 1.2 for a cushion and use that for the minimum I need on a battery device or power supply. If you use a converter to buck/boost/SEPIC you also need to factor in that current.