I have seen tons of videos of "leave me alone" boxes around, and I decided to make my own. I know basically nothing about electronics, so I am attempting to build a 100% mechanical one. This machine is powered by the DC motor, which constantly spins in one direction, even when the machine is not in use. the starting and stopping, and the switching directions is all done mechanically, and I did not "cheat" by making the arm on a reciprocating axle that automatically retracts it regardless of the position of the switch.
Anyway, I designed and built this fully working prototype in about 4 hours from about 300 pieces. I plan to encase it in a box in the next day or two, and I will post a video then. This machine is a close runner-up to my automatic transmission as the most complex mechanical device I have ever built with K'nex.
How it Works - WARNING: TL;DR
I will try to explain this as well as I can for the 2 or 3 people who actually care. The blue lever on the far left is the "switch" which turns the machine on or off. When the switch is pulled, a series of needlessly complex linkages cause 2 things to happen. One: the transmission in the center of the device (an extremely downsized, re-designed version of the one found in my automatic transmission) is switched in to the "forward" position. Two: the "clutch" is engaged, by pulling the red gear farthest to the right into position so it meshes with the gear coming off the motor, as well as the drive gear for the rest of the machine. 12 gears later, the large L-shaped arm in the center of the device swings forward and hits the switch. Due to the design of the linkages, this only switches the transmission, but does not disengage the clutch. The transmission reversed, the arm goes back into its resting state. At the end, it engages a rod which slides the clutch gear out of position, stopping the machine in its starting point. (hopefully this will be made clear by a video, maybe...)