CHDK (Canon Hackers Development Kit) is a widespread unofficial software add-on for cheap digital CANON compact cameras that can do amazing things with them. Check it out on chdk.wikia.org, it is unbelievable. The same with SteroDataMaker.

In 2010 I gave a 4-days workshop on CHDK basics and on making simple DIY hardware accesories for these cameras. Organized by Natalia Borissova/aa-vv.org, hosted by Stephan Kallage/West Germany
more info HERE