Last year, LEGO’s Build To Give campaign challenged people to build and share a heart, and I really wanted to build one that incorporated some sort of movement. I decided to keep it simple, and ended up with this stylized heart that would ‘beat’ when you turned a crank in the back.
You can see a demonstration of it in action in the video, and continue reading for more details and free building instructions. A full build kit is also available from BuildaMOC. I think it would make a great gift to a loved one, especially with Valentine’s day on the horizon.
It’s a pretty simple design, with a single cam that pushes each lobe up as it rotates past. The result is that the two lobes rise and fall one after the other, with a pause between each cycle, making it seam like the heart is beating.
Build Notes
The build should be fairly straight forward. If the lobes don’t fall freely, or seam to stick, I find it helps to insert them fully then wiggle them a little bit. This will help to ensure none of the adjacent pieces interfere with their movement.
![](https://jkbrickworks.com/jkbw/wp-content/uploads/2024/01/heartBeat800.jpg?x73049)
The building instructions also illustrate how it can be motorized using a Circuit Cubes Geared Motor Cube. I really like these motors as they are quieter than LEGO motors, and rotate more slowly, so they do not need to be geared down as much.
The parts list includes all the parts needed to build either the hand cranked or motorized version. If you are just building the hand cranked version, there are a few parts in the inventory you don’t need. Specifically, those parts added on Steps 16, 17 and 18 in the building instructions.
![](https://jkbrickworks.com/jkbw/wp-content/uploads/2024/01/heartMotorizedBack800.jpg?x73049)