I've been trying to find the simplest, easiest, and cheapest video overlay (NTSC) using a PIC to allow me to overlay GPS coordinates and speed on-top of my underwater video camera stream. So as we 'survey' the Columbia riverbottom during Fall Chinook Salmon fishing we can track our path with GPS and the bottom. For when we find one of those GIANT Toyota ships lying at the bottom of the river we can find it again ;-) 
Anywho - I've been trying to modify J.A.Sanchez's "Video Stamp" design and software (see http://www.circuitcellar.com/ April 2007) to overlay my GPS strings. As you can see, the design is simple - a 18F2520 uController, 3 resistors, and the connectors. It works great
for basic debug and text output to the video screen, but when overlay'ed on another video signal, the sync's and raster seem to be out-a-wack. So... more work on this one. Thought I'd at least post it 'cause it is cool and worked the 1st time!
Next steps are to try to sense and adjust the timer interupts, or to role-my-own from scratch... but that is not as fun.
Next steps are to try to sense and adjust the timer interupts, or to role-my-own from scratch... but that is not as fun.
