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Are there Arduinos (or clones) that can be powered with one or two AA batteries or one CR2032 3V battery? (it would sleep 99% of the day, and only send a few bytes per day)

If so, will they also have a +3.3V or even +5V output (produced by an internal step-up chip) that can be used by another chip?

(I know it might sound like having one's cake and eat it too, but maybe it exists?)

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  • there's a lot of 5v output boost dc-dc converters that would work a treat for AA batteries.
    – dandavis
    Sep 26, 2017 at 19:05
  • @dandavis do you think there are ready-to-use Arduinos or clones that would work with 2 AA and include a 3.3 V or 5V boost, out of the box?
    – Basj
    Sep 26, 2017 at 19:14
  • not that i've seen, although i think they make power/battery shields that would handle it.
    – dandavis
    Sep 26, 2017 at 21:07

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The modern low voltage versions of a bare ATmega chip can run from either 2xAA or a lithium coin cell - you wouldn't want to use a voltage regulator, as that is not only unnecessary but introduces losses but increases the required input voltage by its dropout meaning your circuit will fail earlier in the discharge curve that in it would without.

Bypassing the regulator on an Arduino Mini style of board is possible. You probably do not want a board with an on-board USB-serial solution.

You'll need to make sure the clock rate is low enough for operation at the rated voltage (and for sleep efficiency). This might involve using the fuse for the internal oscillator and ignoring a crystal/resonator that might be present, though if your board was originally intended for 3.3v operation it might be okay.

You will also need to set the brownout detector to the lowest voltage or disable it entirely - this again is in the fuses.

A boost converter to a higher voltage is possible but may not be a good idea, especially from a coin cell. This is because to supply 1 milliamp at 5v, a boost converter must draw 2 milliamps at 2.5v - and then a bit more, to account for its own losses. If you go shopping for a boost converter to use, make sure it has an enable, look at the quiescent power consumption when disabled and enabled without load, and look at the minimum input voltage.

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  • Thanks @ChrisStratton. Do you think there are ready-to-use Arduinos or clones that would work with 2 AA and include a 3.3 V or 5V boost, out of the box?
    – Basj
    Sep 26, 2017 at 19:14
  • Not that I'm aware of. Note that asking for recommendations of products to buy is off topic here.
    – Chris Stratton
    Sep 26, 2017 at 19:15
  • Actually, I do think of one possibility - before they wisely abandoned the idea, some "drone" flight controllers were Arduino based and included a boost converter to allow 5v operation from a single lithium polymer cell. This tends to have a higher minimum voltage than the power sources you are looking at, so you'd have to investigate the actual minimum operating voltage. But it would be best to get the higher voltage requirements our of your design entirely - and realize that for micropower stuff you'll likely end up making your own board anyway.
    – Chris Stratton
    Sep 26, 2017 at 19:18
  • Good idea! If you find a source/link about such Arduinos I'm still interested :)
    – Basj
    Sep 26, 2017 at 19:19
  • That's probably too fine a distinction - besides, if someone said "yes that product exists" wouldn't your next questions be "what is it called" or "who sells it"?
    – Chris Stratton
    Sep 26, 2017 at 19:19

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