Hi ! After watching Matthias Wandel's solenoid engine video a few years ago, I thought it would be interesting to try build a similar 3D printed one. All the parts are not 3D printed but easy to find.I used a solenoid with a range of motion of 10 mm so the shaft must have a 5mm crank (the bent part attached to the link of the solenoid). The size of the crank of the switch doesn't matter.

Cheers, Arthur