These are printable parts for an electrostatic field mill design I thought up utilizing a pc case fan brushless motor. Basicly you print them. Cover them with foil and tear apart the fan to get at the magnet ring and fan morot coil. The project also uses some 3mm metal rods from an old CD rom drive. I'll include a pile of step by step photos of it being put together.This is a printable electrostatic field mill. It allows you to monitor static electric buildup in the atmosphere. It's built from easily obtainable parts any computer geek (like me) should have lying around. An old pc cpu or case fan (with a 3mm shaft and ball bearings) a dead cd rom drive (for more 3mm metal rods) about 2 feet of aluminum foil some spray adhesive or some other kind of glue. Print the parts. Collect the parts from the fan and cd rom and follow the pictures. I've tried to put them in the order it should be built. basically make sure the spinning shutter and the solid ground plane are electrically connected. the middle (sensor plate should be electrically isolated from the rest of the spinning components. you measure across the sensor plate and the shutter plate to get the readings. I suggest googling field mill. for more information. this was just something I made to see if I could!