RE: Digispark ATtiny85 Lowest Power : Does Anyone Know?

michaelkellett — Fri, 27 Nov 2020 15:00:17 GMT

If you only ever use a 5V or less external supply removing the 7805 (and shorting its input to output) will be as OK as this design ever is.

According to the schematic there is a diode which allows the board to put power back into the PC but does not allow the PC to power the board - weird.

From the ATtint85 data sheet:

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If you can get the processor into power down mode and use the WDT to wake it occasionally your batteries should last a while.

If you use an ATtiny85-10 it will work down to 1.8V, but max speed 10MHz.

Remove the regulator, link out the regulator footprint, use a 5V supply (current limited to maybe 30mA) and USB for debugging, connect a battery for running.

Remove the resistor in series with the power-on LED to save its current.