Remember slide shows? The ones that used a carousel projector and real slides? [Brian] wanted to bring his slides into the digital age but was spending far too much time scanning in the 35mm relics. He set to work and built a rapid slide digitizer using a projector, a DSLR, and a microcontroller.
His system centers around an AVR microprocessor, the ATtiny2313. Some DIP switches are used to set the number of slides to be scanned, and the timing for synchronizing the projector and the camera. Using two relays, the cable release for the DSLR and the remote advance pins on the slide projector are connected to the AVR. [Brian] used a macro lens and sets the focus, exposure, and f-stop manual. Once everything looks good the touch of a button quickly steps through the entire carousel at about 1 slide per second. A small video of the process is embedded after the break and his writeup has some comparison photos between a slide scanner and this setup.