The following are cameras and assorted photographic devices I have built over the past few years. Not an exhaustive list.
Canon P TTL (2015)
Adding TTL (through-the-lens) metering to a 50-year old rangefinder camera, using a light-to-frequency converter, ATtiny85, and HP bubble display.
Field 23 (2010), Field 23 ACME (2011)
Field camera based around the Mamiya 80mm f/2.8 lens and the 2x3 format. Was intended for 2x3 sheet film, but also found use with a 6x9 roll film back, and a 3x4 Polaroid back. A later iteration converted the rack-and-pinion focus to an ACME leadscrew type focus mechanism, and leather to waterproof composite bellows.
Accessories and stuff that didn't quite make it
Exposure metering, gum tin, and papercraft cameras!