A small printable Van de Graaff generator.

Designed to use common household parts, once you have the printed parts...

The MakerBot is currently not cooperating so I haven't tested this yet. The prototype it's based on was made of pvc pipe and was about twice as tall. It generated around 6kV (old possibly uncalibrated electrostatic voltmeter) and visible 2" sparks.

vdg.scad is the openscad file used to generate the .stl files. This was my first ever project using openscad so I wouldn't classify it as "parametric" but I did add comments to where most of the size definitions are. Next time I'll have a better idea of how to program using variables.

vdgwhole.stl is both pieces and should be able to be printed in one go. If you want to print separately I've split them into vdgshell.stl and vdgwheel.stl The .stl files are set up to use a dc motor with a 1" outer diameter.

Acquire needed parts.

Use a can opener to remove the top of a pop can, wash out the inside, and be careful the edges may be sharp. This is going to be the charge collector at the top.

You're also going to need a small glass tube. The best way is use a couple pairs of pliers to hold the ends of a glass fuse over a candle flame. The glass will start to glow and you should be able to carefully pull out the wire leads. Make sure that the tube spins freely over the wire or nail you're going to use for an axle.

Assembly:

Wrap the printed wheel in electrical tape. The rubber band traveling between the vinyl tape and the glass tube is going to generate the charge.

Slide the wheel onto your motor's shaft and secure with hot glue if needed.

Place the motor in the large hole in the side of the tube so that the wheel is centered inside. Glue in place.

Stretch the rubber band over the wheel and glass tube. Slide the axle through one of the top holes, through the glass tubes, and back out the opposite hole. The rubber band should be tight enough that it can't flap back and forth and make contact with anything, (because you will lose the built up charge) but should be lose enough for the motor to spin freely.

Next you need to make 2 wire brushes to collect the built up charge. Strip the end off some stranded copper wire and fan out the wires a little bit. Stick them through the holes in the top and bottom. You want to position the wires so they're close to the top and bottom of the band, but they shouldn't be touching anything. Once you've bent them into place glue them down.

The top wire gets connected to the pop can, strip the end and place it on the lip, the can should fit snugly over it.

The bottom wire is your ground. You can extend it out to a wand, or just hold it in one hand and shock yourself with your other hand.

You're Done! Connect the motor up to the appropriate power source. You can tell it's working by holding the back of your hand near the can, the hair on your arm should start standing up.