Finally successfully wrote a sketch that logs the date and time to my microSD card when a button is pressed (using Real Time Clock from Adafruit).

The setup – microSD breakout board to left, RTC to the right

The results, printed to the Serial Monitor:

Right now, the sketch detects button states so only one timestamp is recorded when a button is pressed. Otherwise, multiple timestamps are taken for the duration the button is pressed down. However, now that I have added the RTC, I can’t get the sketch to work with more than one button, although I can get all my buttons to log data when I take out the button state code. So close, yet so far. → Read more