Powering Arduino Pro Mini 3.3V?

Hi everyone,

I am looking to power my Arduino Pro Mini 3.3V. I tried using a CR 2032 with a 5V step-up regulator from Pololu to the RAW pin and it worked for a short while before dying. I am very limited on space. Does anyone have any suggestions to fix this problem? I've considered a 3.7V 110mAh LiPo but the application would prefer if it wasn't rechargeable.

Any suggestions??


Is it a 3.3V and 8MHz Arduino Pro Mini ?

The 'raw' is the input to the voltage regulator, and the Vcc is the 3.3V output of the voltage regulator for the ATmega chip. You can run the ATmega chip directly from a 3V battery, but only down to 2.7V. Remove the voltage regulator, and connect the battery to Vcc. No step-up, no Lipo, just the battery directly to Vcc to the ATmega chip.

A little more voltage would be better, like 3 AAA batteries, or a Lipo, or a 18650 cell.

You can go lower, just change the brown out detection fuses in the Extended Fuse Byte, bits 2-1-0 (7-3 not used) Table 28-6. Extended Fuse Byte for ATmega328/328P

110 will yield 1.8V typical 111 will be off

Change the byte in the apprporiate boards.txt entry, reburn the bootloader with the IDE, then reload the sketch.

CR2032 bad choice no matter what, only couple hundred hrs capacity.

Connect the battery to the VCC pin, not RAW.

Okay so 3V lithium ion coin cell is out of the question? 3 AAA batteries is too large for the application. Thoughts on an AAAA battery?

I'm really trying to avoid rechargeable, but please let me know if that seems like the only feasible option.

Thanks again!

Last time I looked at the datasheet for a lithium coin cell it said, IIRC 2mA maximum current draw.... So no its not up to the task really.

A stack of 3 AG13's though, no problem (1.5V alkaline coin cells).

So use 2 AAAs.

A Lipo or Li-ion battery has low leak, and they come in all sizes. Use a cell with a protection circuit included to shut down when the voltage is too low.