The proof of concept on the left (done a couple of years ago), and today's v1 version!

Proof of concept, up close...The microprocessor is TOTAL overkill here

Todays version, a slightly more appropriate microprocessor, better power supply regulation too, and more features! (a remote control, and can do either 1 minute or 1 second intervals)

Apart from getting 2 pins on the micro confused (PCINT0 and INT0, easily done!), I also forgot to tie RESET to 5v, so the microprocessor never did anything, just sat there in reset all the time!. Hence a small hardware patch on the underside!