Here’s a video of the Super Mario Bros. Toilet Warp Pipe in action. Notice that I don’t have to flush the toilet to activate it. This way you can amaze your friends without wasting water.







It also works when using your foot to touch the handle. Even germaphobes can enjoy the fun!









Extra Notes

Finally, please be aware that this sort of touch sensor can be unreliable because of the vagaries of static electricity. Sometimes it will trigger before you touch it, other times it will trigger as you move away from it. Sometimes it won’t trigger and other times it will trigger multiple times. Actually flushing the toilet sometimes activates the circuit more than once. I’m assuming this is somehow caused by the water flowing through the grounding pipe. If you can’t make a connection to a metal water pipe, that’s not a big problem because the “grounding wire” for this circuit doesn’t actually have to be at earth potential. As long as your electrostatic field is strong enough to induce charge to move then the circuit will work, just not as well; also there will be a period where re-touching the handle won’t reactivate the circuit because the induced charge hasn’t dissipated yet. If the sensor doesn’t trigger try rubbing your pants on your leg a little bit to generate some static or touching the grounding wire to balance the charge. Sealing up both ends of the pipe with the plastic disks cut down on the loudness of the sound effect and also makes it difficult to replace the batteries; on the other hand, not sealing the pipe could leave the circuit vulnerable to the high humidity of a bathroom. If I had this project to do over, I'd like to see what kind of results I got by triggering the sound effect with a strong magnet attached to the flush handle and a reed switch inside the reservoir, opposite the magnet.



Comments

Constructive comments on how to improve the circuit and my fuzzy understanding (mis-understanding?) of static electricity circuits are greatly appreciated; book titles and article links would be most helpful.