I thought it might be interesting and maybe even helpful if I shared the webpage for the Pure Data/Arduino audio/video course I just finished teaching. This was a one-semester undergraduate-level course I taught at Wichita State University. Most students were electrical/computer engineering students that had minimal applied experience with programming and circuitry before signing up for the course.

Main course page:
http://cratel.wichita.edu/blogs/ee577aspring2012/

Student final projects with explanatory video and code:
http://cratel.wichita.edu/blogs/ee577aspring2012/category/final-project-report-video/

The web page for the course includes all assignments, my notes, schedule and a forum where students asked questions, shared cool projects they found, etc.

One thing I wrote as an example for the students in the class was a color tracker which could track primary colors. I thought I saw a conversation on the list earlier were somebody was writing an external for color tracking, but at least primary colors can all be tracked in Gem. Maybe it's obvious but in case it's not:
http://cratel.wichita.edu/blogs/ee577aspring2012/forum2/code-group3/pd-patches-forum4/2-color-trackers-thread16/

-John
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John Harrison http://alumni.media.mit.edu/~harrison