nice work!!

Very cool! It looks like only used a digi cam for input no?  Did you do image processing on the MBed  itself or did you use something else? Also, what kind of algorithm did you use to recognize a smile from not smiling??

I really haven't tried anything as sophisticated as image processing.  I took the simple route.  Sony makes digicams with "smile detection."  In smile detection mode (three levels of detection available), an LED illuminates when the camera detects a smile (I monitor the LED via mBed to control servo motors for the mouth and "LED eyes").  Low cost Sony cameras have this feature and it works pretty well, but most Sony cameras like to shut down after about 20 minutes of detection, and there is no straightforward way to power the digi cam from AC.  Certain (translate to more expensive) Sony cameras will operate on a "party base."  This is intended to scan around a room and take photos of people when they smile.  The party base passes power from an AC source through to the camera and it keeps the camera on and detecting "forever."  LED's on the base turn off briefly when a smile is detected.

The party base automatically pans and tilts and follows people--I plan to disable that soon so that the camera will quit "moving around hunting subjects."