Published December 24, 2020
WOOO. In sort-of order, today I learned: how to read from SD cards, how to play wavs from SD cards, how to boost speaker volume using a transistor, how to limit transistor current using a resistor, how to trigger interrupts for Arduino sleep modes, how to change what shape causes an interrupt, which pins are and AREN'T interrupt pins, how to hijack the button on an Easy button (not easy, actually).
Here's the end result: An Arduino rig that powers off until the button is pressed, then plays a random sound file from the SD card before powering off again. Gonna solder everything tomorrow and move it to battery power.