This year for Valentine’s Day I decided to get nerdy and make something electronic for Caroline. I first tried to make a animated LED heart with a “joule thief” and a single AA battery, but I couldn’t make a suitable air coil. So, I decided to modify this circuit to make a throbbing LED heart. The circuit uses a 555 timer, NPN transistor, 12 LEDs, a capacitor, and two resistors. The schematic is below. I only drew in 6 LEDs in parallel, but there should be 12.

This is what the finished product looks like:

And a video of it in action: