A group of photographers at HDRLabs have created their own. Called the Open Camera Controller (OCC), it's based on an older Nintendo DS portable gaming console that controls the functions of Canon DSLR cameras, as well as Olympus and Sigma shooters. Along with some coding and a new hardware interface, the HDRLabs staffe claim they can make the connected DSLRs do things their manufacturers never intended.
This includes the ability to capture timelapse shots with a built-in alarm and triggering the shutter by clapping your hands instead of pressing the button.
The HDRLabs team came up with the idea after having to shoot HDR images for film production using Canon cameras. Canon only allowed them to a three-shot method for bracketing shots, when the users preferred to have as many as 11 stops to bracket their metered exposure.
While HDRLabs does not sell the OCC, it does provide comprehensive instructions on how other people can build their own. HDRLabs does offer five open-source apps to download for free once users have the interface created and ready to go. This includes the aforementioned Sound Trigger, Bracket, Intervalometer for timelapse as well as Astro Script for creating advanced shooting programs for astral photography and eManuals for quick referencing in the field.
The OCC was tested with the Canon 30D, 40D, 50D, 5D and 5D Mark II, with Sigma DSLRs, the Casio EX-FX1, and the Olympus E-P1 also working, albeit with some issues and limitations.