Valentine’s Day Large LED Heart PCB

Valentine’s Day Large LED Heart PCB


A large heart with 20 individually controllable LEDS using 4 pins on an ATtiny 45 with Charlieplexing This is an easy to solder project, as all components are trough hole, except for the large and easy to solder battery holder Who would not like to be pledged eternal love to by their valentine giving them a large blinky LED heart Pendant!

“SaltyPaws” writes:

  • I developed this project, in order to introduce my daughters to electronics. This pendant can be used to introduce STEAM concepts at many levels. It can be used to introduce electronics, teach trough hole assembly/soldering and programming.
  • This is a basic demonstration of the Charlieplexing principle. The heart can be used stand alone or in a pendant.
  • I used FreeCAD in order to design the heart shape. Unfortunately at the time of designing, the offset tool was not available in FreeCAD (I know there are work arounds), and I completed the snap on case design using Fusion360.
  • I skipped the breadboard prototyping phase by using the proven Circuit design from designer2k2. The first version of the PCB worked as per design.
  • For printing the case, I used PLA, 40% infill and 0.2mm layer height. It easily snaps onto the PCB, and while the stand offs include m3 thread, the M3 x6mm bolts are not required as the 45 degrees edge on the case holds it in place. I would not reccomend using without case as the back of a trough hole PCB can be demanding blood like a Vampire from Transylvania.

Valentine’s Day Large LED Heart PCB – [Link]

About mixos

Mike is the founder and editor of, an electronics engineering community/news and project sharing platform. He studied Electronics and Physics and enjoys everything that has moving electrons and fun. His interests lying on solar cells, microcontrollers and switchmode power supplies. Feel free to reach him for feedback, random tips or just to say hello :-)

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