I’m wondering what’s the simplest and possibly cheapest portable power arrangement to keep an ATMega328P-PU or ATMega328-PU alive.
There are plenty of approaches involving a power regulator (and a power source > 5v) or a boost regulator (and a power source < 5v). However, I’m wondering if it’s possible to simply power a 328 directly off some kind of battery technology which produces a voltage within the right sort of range, to maximise simplicity and minimise cost of tutorials and demonstrations.
So far I’ve been speculating about…
- 3 AA NIMh batteries, coming in at about
3.6V4.2V when fully charged
- 1 Lipo battery, about 3.7V when fully charged
…but there may be other arrangements I should consider or concerns I should have.
I can’t find a pre-existing discussion about this as I think most projects assume they are using a full-fledged Arduino including a regulator, or that 5V is important for some reason. Anyone have experience of running off batteries without any regulator?
In our case we’re relying on Arduino-compatibility, but we’re building simple ATMEGA328-based projects direct on stripboard, like this…
…so the minimum component count and most consistency between running off USB and running portable the better. I don’t think the exact voltage matters for us, so long as the microcontroller is running stable.
When any battery technology starts to go flat, I guess we’ll need a 328P with picopower to handle a graceful brownout, though. Don’t know what the consequences would be of using the simpler 328 without picopower on a battery-driven project. Perhaps it could corrupt the bootloader when it starts to run random instructions?
Update: I finally found this thread http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1295580639 but seems to be inconclusive, with Jeenode offered as an example of running at 16MHz with low voltage and some saying chips will happily run down to 2.5 volts, whilst others saying it won’t work.