Greeting guys,

Second introduction on myself, I am from Johor, Malaysia and currently an Electrical and Electronic Engineering student from University of Nottingham Malaysia Campus.

After some hard works after around 2 months, I finally got my MT box working and I am satisfies with it so far.
Due to my old laptop, so the flash performance and responses is a bit slow.

Here is my FTIR based 17” LCD Multi-Touch Screen video with some flash demos:

Blob and Sensitivity Testing:

Components Labeling: (Click to view enlarged picture)

Numbering:
(1) LCD Matrix (From LCD Monitor)
(2) LCD Driver Circuit (From LCD Monitor)
(3) LCD Power Supply (From LCD Monitor)
(4) LCD Backlight (From LCD Monitor)
(5) LCD Control Buttons (From LCD Monitor)
(6) VGA Port
(7) Infrared Bandpass Filter
(8) PS3 Eye with SPC900NC lens mount
(9) ATX Power Supply
(10) Power Inlet Connector
(11) USB Socket
(12) Magnetic Switch
(13) Cooling Fan
(15) 8mm thickness acrylic plate
(16) Infrared LEDs
(17) 3mm thickness acrylic plate (for support)
(18) LCD Panel (From LCD Monitor)

Schematic: (Click to view enlarged picture)

This MT Box built using:
- Samsung 740N LCD
- 8mm thickness acrylic
- 30 Osram’s 880nm Infrared LEDs
- 3M Crystalline Windows Film
- ATX Power Supply
- PS3 Eye Camera with SPC900NC lens mount
- 880nm Infrared bandpass filter
- Miscellaneous hardwares
- Knowledge from NUI Group Community

Where I get those hardwares:
- LCD monitor (Second hand @ RM200) - From lowyat.net forum member
- Acrylic (RM30) - From acrylic shop in Jalan Pasar, KL (Map location), the shop will cut it to the dimension you want
- Osram’s LEDs (Price varying) - From RS Malaysia: http://malaysia.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0585242
- ATX Power Supply (Second hand @ RM20) - From local computer shop
- PS3 Eye (RM190) - From one of the shop in Sungei Wang Shopping Mall, KL
- Infrared filter (USD$ 39.50) - From eBay via middle person
- Woods, nails, wires, tools, etc… - From local hardware shop

Running on Gigabyte N411 laptop with specs:
- Intel Centrino 1.6Ghz
- 1GB DDR333 RAM
- Intel Integrated Graphic
- Windows XP SP3

Thanks everyone!

Very nice work… what are you using for compliant surface? its working really well

Thanks Taha, I did not apply any compliant surface on it.

Interesting do you have anything on top of your acrylic?
where does the window film go?

Is there much pressure needed when dragging to get good blobs?  As this is a problem with compliant-less FTIR setups…

@Taha: There is nothing on top of the acrylic, my finger is touching the bare acrylic. The windows film I put it with the backlight so that it can block some IR coming out from the backlight. I tried to put the windows film on top of the acrylic but too bad it can’t produce any blob at all.

@PeauProductions: I need to apply some pressure on the screen but not much when dragging to get the software regconise the blob. I tried to apply compliant surfaces but maybe my mixing technique or rolling technique or the silicon texture not good enough, the image degradation from the screen was too much until I can’t see what exactly is on the screen. Without compliant surface, it is still ok for me to apply that amount of pressure on the screen when dragging. Therefore what I can do now is try to decrease the threshold value and/or smooth value in tbeta to get the blob recognise more easily when small force is applied when dragging.

Thanks.

Yup, figured as much.

Nice setup , everything in a box !

What’s that backlighting you are using ?

Wow awesome dude!

I recently acquired some free 17” monitors myself, I think I might look into this even more seeing how effective this turned out.

Just need to look into weather this setup is viable using IR light clusters/spotlight DLP style, as theres no way im attempting to solder a 1000 LED’s together.

Eitherway keep us posted on what you’re working on next/doing with this one

@jimiheartz: Thanks, the backlightling I am using is the original backlight disassembled from the LCD monitor.

@Osiris: Thanks, good to hear you got free monitors I don’t think you need 1000 LEDs for a 17” setup lol, but I understand it takes time to solder LEDs.

Well okay have been an exxageration, how long did it take you to solder the 30 you used?

@Osiris: To solder those 30, I think I need around 30mins to 1 hour since my soldering skill still not good and fast enough.

Hey AlexTan, great setup! nice and clean....

Oh, and thanks for using ChalkMT and MatchMT for your demo video!

Where did you buy your infrared bandpass filter?

@Gallinos: I bought my infrared bandpass filter from eBay at BJOMEJAG EBUYER STORE last time and the link is here:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&Item=170219002241&Category=36338null

But I guess the item is not available now so you need to find an alternative to this.

So the thing on the bottom of the box, is that the backlighting from the LCD?  Also what does the infrared bandpass filter do, havent seen those mentioned on the boards much although previously I was more focused on DI setup.

@Osiris: Exactly, that is the backlightling for the LCD.
The infrared bandpass filter on top of the PS3 Eye is to suppress visible light and at the same time allows only infrared light (for my case is around 880nm) passes through it.
This is done so that the camera only sees the infrared light reflected by your fingers.
If without the infrared bandpass filter, the camera sees both infrared (reflected by your finger) and visible (from backlight or surrounding) light and hence this makes the software not able to distinguish between them, and so the blob can’t be detected.

Ah yeah I thought thats what it might be but I also thought newer style webcams like the PS3 would have an IR filter like alot of other ones seem to.  In any case very interesting.  Did you manage to pull the LCD apart safe and sound for the first time?  I ask because in other threads ive read that its a pretty delicate procedure.

Good job AlexTan! i’ll try to build the same table.

Osiris - 05 February 2009 09:41 PM

Ah yeah I thought thats what it might be but I also thought newer style webcams like the PS3 would have an IR filter like alot of other ones seem to.  In any case very interesting.  Did you manage to pull the LCD apart safe and sound for the first time?  I ask because in other threads ive read that its a pretty delicate procedure.

At my first time disassembling the LCD monitor, I did not made any damage to it. I would say the disassembling process is rather easy for me.
But until one time, I accidentally stick the double sided tape on the LCD ribbon, when I want to remove the tape, I screwed up the ribbon, resulting half of my screen display gone.
Nothing much I can do to the damaged ribbon and screen, so at the end I got the whole LCD replaced.
So please do take much care on those ribbons.

Richard Z - 06 February 2009 12:25 AM

Good job AlexTan! i’ll try to build the same table.

Thanks, looking forward to see your setup working too.

NICE

Next is to get this thing played by a LOT of people. The joys of sharing with friends of family is a great exprience :D

Great going Alex!