Multitouch Screen using a LCD

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2008-09-01T15:52:00.000-07:00

This blog is dead because I've open a new blog.

You can check it there.

Have fun !

Gimme the defibrillator...

2008-06-23T12:49:00.000-07:00

This is not the first post claiming that I'm still on and once again I got nothing new. I've had something more important to do, I think everybody knows what it's like to try to find moments to move on a side project.

Anyway I hope this summer will allow me to really work on multitouch (try to improve what I called circle detection, more details here).

Quick Update

2008-03-21T12:37:00.000-07:00

Rear illumination seems to be ok but there are 2 issues: the first on is that I can't obtain a white color because it's possible to see through the screen. I think using a completely white box is the only way but i'm still waiting for an advice on it.
The second issue is that the blobs are not good enough to track them (no good contrast). I think the only way is to use some kind of background removal (I mean compare the image with a prerecorded background).

That's all !

Edit: I've forgotten to show you how it's like : here is a video.

Still Alive

2008-02-28T15:17:00.000-08:00

I'm still alive, don't worry ;-) I'm just busy so my project isn't making progress.

Just an idea to share, maybe it's possible to track the light reflection (infrared light) on a hand nail like this:

By placing a few light sources, it's possible to get white dots/lines. The problem is that it's pretty hard to inculde the thumb's nail in the process.

I'm bulding a kind of a line to have a lot of sources and see if it works correctly. Right know I don't know how to generate a click event, the natural way is to use stereoscopy but maybe by hiding the top of the clicking finger (~ 0,5s) and go back to the original position (like a click on a mouse but in order to hide the nail).

I'm pretty disapointed because its a strange technic but I really don't want to disassemble a screen so I'm looking for a solution using front detection.

Happy new year

2008-01-13T07:04:00.000-08:00

Yeah that's right, I'm late but I wish everyone a very happy new year ! (2008 will be the year of multitouch technologies guys ;-) ).

I didn't work these holidays, but I've made a picture of the principle of my project :

(full size here)

I thought that it was easy to make a touchscreen using 2 webcams but is seems to be hard to compute. So I'll use 1 webcam but the box will be deeper (+5 cm). This is a big box but the computer will be inside (considering the 1 webcam system, 40*29*27 cm). Normally, it will be smaller in the end (let's hope so...).

Concerning the "flat illumination", it's the system used by nima on the NUI group's forum. I have tested 2 rails of leds and it works pretty well. Of course it is possible to hide an area with your hands or fingers but I didn't succeed in doing this. The problem is the blobs are pretty big, due to some filters which are necessary to have an even ligthing.
The first test of the frame should be next week.

Merry Xmas

2007-12-27T08:02:00.000-08:00

If there is someone reading this blog, merry chrismas ;-)

I made one video (here). I'm waiting for a screen in order to build a frame with IR leds.
That's all (hey, it's chrismas time ^^).

Once again, merry chrismas and happy holidays !

Still on the road...

2007-12-10T15:17:00.000-08:00

I have received my acrylic sheet so I'm running some tests about the silicone rubber...

A french guy on the NUI forum try to use a silicone caulk in order to have a cheap silicone rubber. I'm on it and I'm experiencing some troubles because toluene is a necessary component and I don't have it. I'll try to get some asap.

I also tried to use a really thin sheet of plastic and put some water between it and the acrylic sheet. The result is pretty good, I see no big difference between this setup and the silicone caulk, but I didn't dilute the caulk with toluene, maybe that's the reason why there is no difference. Anyway, there is a video here.

The blobs aren't good because the sides of my acrylic sheet are almost opaque.

Btw, I must finish another project this week so I won't post a message before next week.

Fast and (not) furious

2007-11-28T15:01:00.000-08:00

I've ran some tests today, you can view a picture by clicking here. I won't comment it but I think I'm gonna stay with a normal FTIR solution (there is no acrylic sheet yet, just a screen + a rail of leds).

First test

2007-11-25T06:07:00.000-08:00

I do not have an acrylic sheet so I used the screen itself. Like nima said here, using the TFT as acrylic should be ok. I wired 3 leds and here is the result (i'm sorry the quality is terrible).

The 3 dots are the leds, and you can notice blobs under the middle led. They are hardly visible, because there are 2 layers of IR filter and I forgot to remove one, but the blobs are visible when there is only one IR filter. Moreover, I have 5mm leds and the screen is 2mm thin...

The only problem is to avoid extra lighting. I used some basic paper, it stops IR very well and you can bend it.

I don't know how many leds will be necessary. My led model sucks (5mm, 940nm), but I'll try to continue with them. My next step is to build a led rail (25 leds) in order to run a real test.

IR Webcam

2007-11-24T06:54:00.000-08:00

Ok... it was pretty simple...

The first thing is to get this little screw by doing what they say here :

http://www.instructables.com/id/Making-a-Night-Vision-Webcam/

When you're done, all you need to do is to remove the small circle on the top (I used a knife).
There you go :

As you can see, this is the IR filter. Remove it with a tiny screwdriver (it is not glued) :

To block normal light, I used a small part of a floppy disk that I fixed on the other side :

The result, testing one of my LEDs :

That's all folks, have fun !

One week later...

2007-11-23T16:13:00.000-08:00

There was a problem with the post office or something so I wasn't able to work on the project. Anyway, my order is home now and I'll start to set up the webcam tomorrow, in order to test the LEDs.

The webcam is a Logitech Quickcam Messenger. Some people told me that it is possible to make it work with IR but it's hard, so if I don't kill the webcam I'll post a review on this step. Maybe it will avoid some "unwanted effects" for those who possess this webcam.

Order #1

2007-11-15T13:37:00.000-08:00

Ok, i'm not alone on this one thanks to the guys of the NUI Group community, so i'm gonna make a "FTIR" multitouch screen.

I bought 50 IR leds (20 €) in order to test some basics using a 15" screen (out of order, but it's not important). I bought a cheap webcam (logitech, 20€). I hope it will do the job.

The thing i have to keep in mind is that i wanna build a mobile touchscreen, so i'm not sure about the backlight (by mobile i mean something not to big, like a 30/40cm cube). A led based light source is what i wanna test, and i'm still trying to implement it.

In the meantime, feel free to participate !