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Hi all. I would like to run an 328P at low power, will it be OK running from 3x AA batteries? At what voltage is it likely to stop running?

If I used the internal 8MHz clock, would that improve consumption much? I want to make a IR remote control, will running at 8Mhz screw the sketch up - timings etc?

Thanks
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You might want to read this for more pointers on running in minimal power: http://www.gammon.com.au/power
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Hi all. I would like to run an 328P at low power, will it be OK running from 3x AA batteries? At what voltage is it likely to stop running?

3 batteries is fine.

If I used the internal 8MHz clock, would that improve consumption much?

The datasheet says that will save you about 4mA.

I want to make a IR remote control, will running at 8Mhz screw the sketch up - timings etc?

That depends on the sketch....and my crystal ball is in for repair.

OTOH you should spend as much time as possible sleeping so running at 8MHz won't save much. If it's going to mess up the timings then don't do it.
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Thanks guys. That is true if it is sleeping I guess 16MHz will be fine.

Probably a silly question but running at 8MHz, will the whole sketch run half speed - IE. delay(100) would become delay(200)?

Thanks
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Probably a silly question but running at 8MHz, will the whole sketch run half speed - IE. delay(100) would become delay(200)?

Not if you configure things properly.

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If you put an 8 MHz bootloader into the part, the timing aspects should be accounted for already. For example, the Promini 3.3V 8 MHz. Will run fine at 4.5V from 3 batteries. I have an RF remote control uses 3.3V 8 MHz Promini, I run it from a 3.7-4.2V LiPo battery. I used a 3 AA battery pack for initial development.
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The 328P still runs with 1.8V (low-voltage shutdown = brown-out-detection disabled or set to 1.8V). So 3 AAs would be fine. When you put it to sleep you can decrease supply current to less than 1 microampere if you switch everything off (think about how you want to wake the controller up again).

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Use lowpower library with powerdown-wake up periodic option and you can decrease current to 1-5mka.
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