Steve Evans (tankslappa on the forum) emailed me recently to present some really exciting developments he’s been working on: a touch screen interface for the Graphics Board:
You’re looking at a little touch screen, placed over the Graphics Board, and as you can see, the size matches up surprisingly well.
Pretty fantastic result! And considerably more precise than I had expected.
He used the touch screen overlay of the Nintendo DS, which can be obtained from eBay. As it turns out, this can be hooked up using 2 digital + 2 analog I/O pins, which is exactly what’s still available on the unused two ports.
All that was needed, were 4 pull-down resistors:
The devil is in the details, though. very small details in fact:
Steve mentioned that it took a considerable amount of patience to get 4 wires soldered to that tiny flexible ribbon, with 0.5 mm between each connection. Clearly, a proper connector would have been a bit more convenient (though just as tiny).
Being resistive and analog, this whole thing needs to be calibrated:
The code for this has been added as a sample sketch called touchscreen.pde in the JeeLabs repository.
BTW, this is part of a new GLCDlib library, which I’ll describe in more detail tomorrow. Stay tuned!