This is the first beambot I've ever built.
I'm not sure it qualifies as a beambot, but it was built in a similar way.
It's no engineering masterpiece, all it does is simply moving forward.
- The energy source is a single 1.5V battery, in a battery socket
- Wheels are from old casette deck; they pressed the magnetic tape against the reading head.
- The motor comes from an old CD-ROM drive, where it served to eject the tray.
It's not a cylinder as usual, but flattened on two sides, so it nicely fits there.
- The aluminium plating is from some old model-train kit
The whole machine is built around the battery socket. It's super simple - there are two wheels glued to the bottom of the socket, and a motor in between, with axis pressed against one of them from side. Nothing too fancy or efficient, but does the trick.
There's a capacitor in parallel to the motor, but it's not important in this design. There's no control logic that needs protecting here.
I've also added a switch on the back, so you can easily turn it off instead of removing the battery.