I’ll be doing something a bit more romantic for Konudagur, next week, but seeing as my girlfriend was working late on Valentines day, I took a break from wireless and frequency counters and software, and whipped up a little love heart.

Not much to it really, just a bunch of LEDs arranged in a heart, driven straight off general IO pins of an ATtiny84, with a pot to adjust the delay between parts. The heart is 12 LEDs, in three groups of four, and can do a nice slow chase, flicker, or appear solid on.

In reality, my board has some extra current limiting resistors, as I didn’t have 12 exactly the same LEDs, and the different diode drops between the different LEDs I had meant they couldn’t share the same resistors. In reality, I also tried to hook up a pushbutton and toggle between two patterns of lights, but I have forgotten everything I learned about switch debouncing, and ran out of time.

Code is available at github, considered to be public domain.

The schematic is available at github as well, in eagle format.

And, here’s a video of it, you can see the different LEDs have a slightly different colour & intensity. (And that I turned the pot the wrong way at first :)