This crazy computer controlled coffee roaster by Matthew Williams is just one of many stunningly elaborate machines displayed on Sweet Marias.

“Here’s my homemade PID’d West Bend Poppery I setup. The PID is a Fuji PXR4 that can be used standalone or interfaced with my laptop via a USB cable. It’s pretty much self-contained except for the external variac that I use to control the fan as the roast progresses. The roast chamber was built out of the original bakelite tube from the Poppery, a 3″ diameter glass tube, and fitted together using hi-temp RTV silicone. There is a screen at the bottom of the tube so you can remove the chamber to dump the beans.”