hi!

im trying to build a lcd mt similar to ms thinsight.

this is as far as i am:

http://www.vimeo.com/1413489

i used kingbright L-932p3c
and l-53f3bt and an arduino.

its all just a test to fiddle with the sensors, thus only crappy processing code to visualize.

todo:
- need to find a diffuser layer, i had to remove the original one
- need to find correct distance between the sensors, emitters and also the lcd
- maybe find better components
- try to do do it with a ftir setup
- maybe use daylight filters

does anyone has good ideas
regarding different componets, filters and the diffuser?

only requirement is, that it has to be low-cost…

cheers

Inspiring, brilliant, I was just wondering how Dell and HP are planning to do it as they have some multitouch tablets on the way in a year or so from what I’ve read.  While I was thinking about it I’d thought about this as a possibility.  I’m not sure about materials though.  If I ever have money again, I’d love to try this.  Keep posting, sorry I couldn’t be more help.

How much emitter/receptor can you handle with an arduino ?

i will put in some multiplexers and shift registers.
so thoretically more than enough. im just not sure if the speed is ok

as i want to have only one LED emitting at time and then capture the sourrounding phototransistors.

im still testing and now ordering new components as well as some ics (analog multiplexers and shift registers)

then there will be a test matrix of maybe 8x8 or so.

Keep up good work !

I’d like an idea to make thin MT installation.
I think it is possible to use some sort of combined emmitter\receiver lasers like in CD players. It can be more compact, than those from video. Or may be emitters can be separated from receivers.
How do you think, what count of those pairs do you need to handle touches accurate and not stop backlight? It’s the main problem for me in this setup.
Those receiver/emitter from CD players are 4.4mm in diameter (or separate SMD components, that are 2x3 mm each in sum 4x3 - about the same). So if you put them back to back you can get phisycal resolution ~120x100 on 24” display with little holes for backlight. It than cn be interpolated to a little bit suitable, but still not high reslution.

Great work , can’t wait to see how this project evolves.As a difussion layer use tracing paper , and also the tracking resolution is gonna be kinda low , tough someone on these forums (and also if you search on youtube for multitouch capacitive) talked/used an alghoritm for interpolating the blobs.

When you get your next test up with 8x8 matrix or whatever you are gonna use please post the results , I’m shure the community will be glad to help and take note from your work.

This might be a new method for multitouch input , and it’d be great for portable solutions.

I’ve read an article on ms thinsight, and they used a combined emmitter/ receiver. It’s called a retro-reflective optosensor . They used Avago HSDL-9100 for prototyping. Its seems quite cheap (2$/piece).
This looks like an interesting new technique. I will probably buy some and do some tests myself.

Here’s the link to the article, its quite interesting, and explains a lot about how its made:
thinsight