Update: this is the final 4 week version. I just realized that I had forgotten to post it.
I have a Canon DSLR camera. I wanted to take a timelapse video of my Aerogarden.The only way to do timelapse is to either connect a PC running Windows or to use the remote shutter port. It is basically a 2.5mm audio jack. If you short one of the 2 conductors to ground it focuses. If you short the other to ground it takes a picture. I rigged up an AVR and some relays to take a picture about every 30 minutes. A script was written to look at the EXIF data in the pictures to overlay the days that have passed.