For Valentine’s Day this year I decided to build this clockwork heart, full of gear spinning action and a little steampunk flair. You can see how it works in this video. Building instructions, and some construction notes, can be found below.
If you don’t have the relatively new long Technic axle pin (the only black piece in the instructions), you can just use a 3 stud long Technic axle with a stud on the end to hold those gears in place (like many of the other gears already do). The newer piece just results in slightly smoother motion.
Towards the end of the video I show how it can be motorized by attaching a Power Functions M-Motor in the back, but you can also attach the motor to the same axle attached to the crank in the same way. You will want to be able to control the speed of the motor though so that it doesn’t spin so fast. You can do this using the IR Receiver and Speed Remote Control, or using the Rechargeable Battery Box, which has a built in speed control.