Hi all, i saw that nintendo ds touchscreen is being sold on internet for only 9.95$ and the description is
This is a 4-wire analog touch screen originally designed for the Nintendo DS. Add this touch screen to any LCD you want! Readings are taken by putting 5V across two of the pins and doing an analog to digital conversion on the other two pins. Full X and Y position can be achieved with only 4 GPIOs.
do you think it would be hard to connect it to an arduino board ?
It should be trivial. Two analogRead() calls, two ANALOG pins, the GND pin, and the 5V pin. You'll have a precision of ten bits, but these devices aren't all that accurate. The Nintendo DS has a "calibration" routine that helps to accurately measure the voltage levels for a specific set of X,Y points, so it can interpolate properly. The Arduino libraries have a map() function that can help this process for you (once you know the calibration data).
It should be simple to do. There is someone playing with this at the moment on some other thread.
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1230462230
Anyway I would start by connecting all four lines to the analogue pins. Then program two of them to be outputs and put one high and the other low. Then take a measurement from the other two (they should be the same) and give you the touch in one direction. Then reverse the procedure, that is make the output pins back into analogue inputs and put the other two to be outputs and repeat for the other direction.
That's how I will start when I have time to play with the one I have. Just a point the connector is tiny so you will need a socket or a very steady hand to solder direct to the ribbon connector.
Does anyone know if there are larger variations of this kind of touch screen available to buy? Like an A5 or even an A4 size?
There are a lot of touch screens available to buy but if they are larger then about A5 then they are not normally 4 wire. Just do a google search for 4 wire touch screen...
I have been playing with a DS touch screen and it is very easy to control things with see:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1243499684
Original touch screen code:
http://mnicolato.altervista.org/arduino/ardtouch.htm
it is in Italian but you can get the general gist or just use google translate...
If you have any questions about how to use the screen then just ask me...
Mowcius
If anybody gets probems copying and pasting the code on spanish site use firefox. ;D