Security-cam continuously compares the previous image and the current image. If an images changes by more than a preset threshold, the image is saved as a jpeg to the MMC card. This is a great project to leave somewhere for a long time in hopes of finding an interesting surprise.
The release version of security-cam had a [wiki:Software-Problems bug] that has since been fixed. Attached below is an updated firmware image and a replacement main.c file with the fix. The fix was committed into subversion at r503.
'''Setting Up Security Cam''' * You will need the following: * CMUcam3, with power and a serial cable * MMC or SD card * MMC/SD card reader on your PC * Format the Memory Card using the '''FAT filesystem''' * DO NOT USE FAT32 which is the Windows Default * Flash the security-cam.hex firmware file onto the CMUcam * Turn off your CMUcam3 and bring it to the area that you want to monitor * Insert the MMC card and turn the CMUcam3 on * Make sure you see the red led blink if there is motion in front of the camera