Generally, here are the materials you will need for an LCD-LP setup.

1. An LCD screen (WITHOUT FFC issues *see LCD section*)
2. A webcam that you can convert into an IR camera
3. If you are converting a camera, you will need a visible light filter.
4. IR LED’s / LED Strips
5. A DC power supply
6. Building materials for crafting a case (wood, aluminum, etc.)
7. Plexiglass/Acrylic/Glass

Okay, now lets get into some details…

1. An LCD screen

I used a 17" Dell 1704FPTt 100-240V, 1.5A, 50-60Hz

You can find a ton of monitors on eBay for under $100 that are in perfecty working condition. If you are daring however, you can purchase a “non-working” screen, and try to fix it up. The number one thing you want to look for in an LCD Monitor/TV is whether or not it has an FFC issue. “An FFC issue is when components (most often controller boards) cannot be moved out of the light path and make the construction of your projector difficult. Sometimes these issues can be impossible to overcome.”

This is an example of an FFC issue…

The nice people at LumenLab have created a very handy chart to find out if your monitor has FFC issues. Here is the link to their website…

Not every monitor is listed, but it will give you a good basis for finding a monitor.

2. An infrared camera.

Now, for this step you can basically choose any ordinary webcam. The multi-touch community generally leans toward the PS3 Eye webcam because of it’s low cost, ability to be easily converted into an IR webcam, it’s high framerate, and it’s recent breakthroughs of being able to run under windows and not just a PS3. Thank you AlexP! Click me!

It’s specs are:

- Multidirectional four microphone linear array
- 4 channel ADC chip
- 16 bit 48kHz
- 56 to 75 degree field of view zoom lens
- 640 x 480 pixels at 60 frames per second
- 320 x 240 pixels at 120 frames per second
- 8 or 10 bit dynamic range
- Uncompressed video or optional JPEG compression

I bought my PS3 Cam off of amazon for $31 =)

For a long list of webcams with easily removable IR filters go –> Here

Along with the webcam you will need a visible light filter or a bandpass filter. A bandpass filter is a filter that only allows a certain frequency of light to pass through. High quality bandpass filters can be found on eBay for about $20. If you want to do it the economic way, you can use the exposed end of some old camera film to make a makeshift filter that works pretty well. If you are choosing this method, you will need to have 2-3 layers of exposed film to create your visible light filter.

LCD-LP stands for LCD light plane. It works by flooding the top surface of an LCD matrix with infrared light, and viewing it from beneath with an infrared camera. When you place your finger in the light plane, it reflects the light down toward the camera, and the camera (running with a program that tracks finger position a.k.a.  “blobs”), transmits it’s viewable area to the computer, the location you are touching.

So far, I have disassembled a webcam (PS3 Eye) and turned it into an IR (infrared) camera, and taken apart my LCD screen. And both still work after being reassembled!

I will be posting my pictures of the processes later, along with steps of what I did.