3/21/10 (2:17 PM)-Experiments with Arduino and Nintendo DS touch screen. I have to use a connector that is still built into a DS mainboard, and I think that is causing some issues with the data, which appears to be very random, but slightly useable. Accuracy improves greatly when I only read the X or the Y data, which is a strange behavior as well.
3/21/10 (7:46 PM)-Ordered touch screen connector from Sparkfun. Hopefully it will fix the inaccurate data issues, which I still have not resolved.
3/30/10 (8:00 PM)-The touch screen connectors came today so I soldered them to headers and experimented. One of the darn things broke, it seems to have been badly manufactured, so I am really glad I got two. Took about an hour of work but I've got good and accurate touch screen data flowing into the Arduino and from there into the computer or my calculator. It only took 5 minutes using the BASIC hook I wrote for UART to make a little program to allow me to draw on the screen with the touch screen. The first version just drew single pixel locations as they came over the linkport, but that resulted in dotted instead of solid lines because of a slightly low sample rate, so I made a second version that draws lines between the samples, which seemed to work much better.
4/1/10 (3:30 PM)-Prototype of the touch screen mod is finished. Electronics fit into an altoids tin with wires going out to the calculator. I just stuffed one of my Arduinos into the tin with the code I wrote flashed on it. Runs for a very very long time on a 9v battery. It is big and awkward, but now that I have it working it should be a piece of cake to make it fit inside the calculator with no external signs that the calculator has been modified.
4/2/10 (8:50 PM)-Finished making a video overview of the project and uploaded it to youtube.