Rail-O-Graph build notes: tapping

Usman Muzaffar and I are working on a telecommunications project called The Rail-O-Graph. It’s a re-imagined Pony Express that passes messages between nodes using a microcontroller on a train. (Initial tests conducted with snakes on a plane did NOT go well.) I’m posting progress videos here as we race the clock to finish by Maker Faire. I previously posted a video of the simple switch > relay > solenoid > switch system here.

Here’s my exploration of solenoids and switches tapping at a constant rate:

The rate wasn’t so constant, until I put a protection diode across the solenoid leads. This was Tod Kurt‘s suggestion. Once again, Tod as saved me from putting the project into a little pile and setting it on fire.