This goes a few steps further with eliminating “bloat” compared to other boards, too — there’s no on-board voltage regulator, and just a single LEDs on pin 13.

Removing the Arduino Pro Mini’s voltage regulator and two LEDs got the current down to 18 milliamps and a recording time of 9 hours. Better. Those are the highlights.

Section 1: Power supply using the AMS1117-5V voltage regulator with lower drop out voltage as compared to common LM7805. Datasheet AMS1117-5V Section 2: Microcontroller ( Atmega8/Atmega 328) to ...