Hello,

i am from Germany and new to this forum but i have been fascinated by multitouch displays ever since Jeff Han demonstrated them. Lately I am also thinking of building my own one because there are many detailed articles on how to and of course of this forum that greatly supports one. I have kept me busy learning about the different approaches FTIR and DI. Both seem to work fine and I haven’t decided for one yet.

But another thing struck my mind: Both use a projector to put the screen onto the surface and infrared to detect the blobs. Consequently they require a kind of box to store the equipment. This is not useful for scenarios where the screen needs to be flat or for small mobile solutions. Before I start my own project on multitouch, are there other multitouch approaches out there? Plasma for example? Or anything that is flat-screen? Are they methods not using infrared? The iphone detects the fingers capacitively. Can anyone explain me how this works? FTIR or DI is clearly no approach for mobile multitouch-screens.

Thank you very much in advance. This forum is really great and I appreciate the help.

iPhone uses capacitive multitouch.
As I understand it, capacitive films are quite expensive when you require them in big dimensions.
There is another method that is also quite expensive, based on sound waves ( I forgot the exact name).
Both approaches would require specific (custom made usually) drivers for whatever circuit you use to interpret the data and feed it back to the computer so it is able to process your input.

sonix is busy with a tft project, if you place a cam with a fish eye lens under it you should be able to make it 10 to 15 cm thick in total (no projector needed)
cant recall that there is somebody here that does detection without a camera, even though there were some test, for example by builder18 and kamelisko with a non camera solution