I was just searching the web and i came across this website. http://www.pcb-dev.com/index.php?option=com_content&task=view&id=15&Itemid=56&lang=english
Based on something that Jeff Han did (http://cs.nyu.edu/~jhan/ledtouch/index.html) using LEDs as input devices to create a multi-touch surface. So my thoughts are if it would be possible to some how put that behind an LCD screen and use it as a multi-touch screen. I hope to be able to make one, it does look quite complicated an there inst much sources on how to do it. This one guy does have a lot of documentation, but nothing very specific enough to how he did it. http://projects.dimension-x.net/technology-and-projects/ledsensors

Just wanted to show you guys this, and get your thoughts on it. I don’t know if it’s already on the forums or not, but i didn’t find anything.

Mike

Microsoft made an lcd prototype exactly like that , on a laptop with ir leds behind the screen , the only problem is the low resolution of the tracking area , hackaday had an article about some german dude that did the same with an arduino and some sensors but no schematics.

Vlado - 27 June 2008 01:03 PM

Microsoft made an lcd prototype exactly like that , on a laptop with ir leds behind the screen , the only problem is the low resolution of the tracking area , hackaday had an article about some german dude that did the same with an arduino and some sensors but no schematics.

yea i was wondering about the tracking resolution, i thought if you used small 3mm leds it would be better. Thats good to know that someone has built something like that. I still would like to try it, it does seam like it would have its advantages over FTIR. One being it could be alot thiner. But it would be harder to build.

I’ve been reading the justDIY notes but for the love of god can’t understand about 80% of them.

I recomend you abandon r&d on this tehnique and focus on your LCD experiments , it’s really not that fessible.

The tracking resolution is really low , even tough you can spruce it up with some clever alghorithms , sunlight would kill your tracking , how would you detect touches under an LCD?

And also MS holds a patent for this tehnique , even Jeff Han who made it possible with multitouch didin’t build a table with it.

Yea the justDIY was above and beyond what i understand. But i agree it doesnt seem to plausible. To bad though it seems really cool. Maybe another time

It is cool , but not as eficient as DI and FTIR.