Monday, March 2, 2009

Received Endlighten Acylic and IR LED Ribbon

So I received my Endlighten acrylic last Friday and some IR lights from I did a ton of tests so read through the stuff below.

Recieving the Endlighten:
Probably the worst packaging job Id seen ever. Like one of those shows where they show you how messed up an item looks after shipping it, that's how the acrylic looked. The very thin paper covering and thin layer of bubble wrap did little if anything to protect the expensive acrylic. Corners were heavily chipped and most of the sides were exposed.

Removed packaging (iphone for size reference) It is about 42" diagonal in a 16:9 ratio:

Brought my LED-LP LCD table over below the Endlighten acrylic and some normal, clear 6mm acrylic:

Looking down at the LCD image with both pieces splitting half the image (Endlighten on right and normal on left):

The pictures above are a little dark, but I could not tell any difference between the two acrylics in terms of clarity. They both looked exactly the same. Thus I think it is highly likely that a DSI LCD setup will work just fine.
Next I placed my projector below the two sheets and used normal computer paper as a diffuser for testing (again, Endlighten on right and normal acrylic on left):

Again I couldnt tell any difference, except that the particles inside the Endlighten diffused the image a little, so that without a diffuser, it seemed like you may not need a diffuser, since the particles stop the image, whereas the clear acrylic let the image go straight through.

On to the IR Lights.
I received a reel of 850nm IR LEDs:

and a test strip of 940nm IR LEDs:

The LEDs look like this close up:

And the 850nm ones glow a slight red which is only slightly noticable when the lights are completly off:

With my ps3 camera that had a floppy disk poor-man's band pass filter, here is what the 850nm LED lights look like:

and what the 940nm ones look like:

The floppy disk isnt filtering for a specific wavelength, but as you can see, the 850nm IR LEDs produce a much brighter image.
I also took a similar picture of a flourecent lamp in my room, with a floppy disk band pass filter:

And a 850nm band pass filter:

Quite a difference.

Next I did some tests. First I used the 6mm clear arylic and wrapped the 850nm ribbons all the way around:

The LED strips from are really easy to use. Took me all of 5 mins to surround the acrylic.
The 940nm strip was too short to surround the entire piece of acrylic, so I did a test surrounding the clear acrylic with both wavelengths and only around as much as the 940nm length was and with the floppy disk as the band pass filter.
The 850nm:

And the 940nm one:

Not too much of a difference with the floppy disk on, but with the proper band pass filter it would make a big difference. Again, the 940nm is less as bright due to the ps3 cam's sensor being less sensitive.

Then I surrounded the Endlighten Acrylic with the full 850nm strip and setup the PS3 cam with the 850nm band pass filter:

Very light pressure:

And dragging with light pressure (peace):

The setup so far works great and I am very excited. The Endlighten coupled with the lights from created the DSI very well and very easily, as everything was setup in under 10 minutes.

Here is the url for buying the reel of 850nm IR LEDs from


  1. you've done a really great job with the pictures, I can feel your excitement from here :P
    How is this endlighten acrylic different from a standard acrylic? And how much did you pay for that size/thickness, compared to a standard one? Thanks for the infos ^^

  2. The Endlighten acrylic has tiny particles throughout it that act as mirrors that reflect the edge lighting to emit the light out from the acrylic. Read about Endlighten here:
    I paid about $200 for the Endlighten after shipping, but it runs about $150 or so just for the acrylic.
    The small, clear 6mm acrylic was $20 after shipping from

  3. ei man,

    Joepen here from nui. I'm new to nui (hehe) and I must say Im very impressed on your work. Been digging threads for a week and I cant seem to figure out how to project the image to the touch screen (pretty stupid huh). Anyways. Im planning to build my own MT and I would be using this blog as my guide. Hope its ok with you. BTW, saw your vid with the piano... I can teach you chopsticks with 4 fingers and both hands.... :-)

  4. Nice pictures and well explained Nolan. I'm going to be starting my own site for newbies like myself to try and get MT flowing in the united kingdom. Ive done the box setup where pretty much everyone starts and now im tempted to pull apart my sony 60" rear projection tv thats sitting in the garage collecting dust. so thought why waste it ;-)

  5. Hey mike,
    Tearing apart a giant TV sure sounds like fun! :) I started my website at to help people get their head around this multitouch stuff. Check it out, it may be of some help.

  6. Did you pay upwards of $200 for the IR led ribbon?

  7. Hey Peau,

    I had a question about the Endlighten acrylic that you used. First off, which specific type did you buy? and roughly what was the cost?

    As well, because the acrylic is diffuse, which allows your to project the image onto it, how would these properties affect I was trying to create a multi-touch surface using Frustrated Total Internal Reflection (FTIR). Because I have the feeling that if the acrylic is diffuse all the way through, then it would cause problems attempting to internally reflect the infrared light. Maybe I'm wrong here, but I just don't want to buy a sheet and find out that it won't work... thanks!

  8. Hey. I've looked at the data sheet for the endlighten acrylic and I'm really confused as to why this specific acrylic was used. As is mentioned in the data sheet, the endlighten uses particles embed in the panel to reflect light outwards, thus reducing the total internal reflected light.

    Isn't that what you want to keep inside the panel, and only reflect the light out when you place your finger on the panel? Like, I mean, if the panel itself is reflecting light outwards, isn't that going to just cause noise all over the place when viewed by your camera? because now IR light is being reflected toward your camera by the endlighten panel, and not just your fingers.

    Thanks for your help Peau!

  9. Okay so Xantus and woody0486 the thing that I think you missed is that my setup is a DSI setup and not an FTIR. In DSI you want the light to fill the acrylic and then leave the acrylic, just like if the Endlighten acrylic was a large IR emitter. Thus it allows diffusion to take place just like in a Rear DI setup. See here guys for more info: And email me if you more questions.

  10. Hey Nolan,

    Wow, thanks for the informative redirect! I couldn't find your email. But anyways, I read through all the different set ups, and I'm trying to decide I guess which set up is better between a FTIR and DSI. They are quite similar but I really like the idea of not using a silicone layer in the FTIR, because that seems kind of cheesy. So I'm interested in the DSI. But I had a question.

    Anyways, looking at the Endlighten website again, there is an option of choosing between 1 sided and dual sided emission. Meaning that you can have the panel only emit light in 1 direction, and I'm guessing it would be way better to choose the side AWAY from the camera outward, and then your finger would naturally reflected the light downward toward the camera.

    Anyways, I'm wondering if you had selected the 1 directional endlighten. Or maybe you could give me your thoughts as if this would be a good idea or not.

    I guess internally there could be some layer or coating preventing any light from being reflected back to the camera by fingers if this one directional panel is designed to allow light in only 1 direction, but I'm not sure, and I hope that its no the case!


  11. Darn.... Nevermind. The product sheet mentions 1 way emission. But to do that, they used a reflective coating on the back. Sorry to confuse you...

  12. Hey Nolan,

    I'm a grad student at Purdue University studying Applied Computer Graphics - focusing on user interfaces for multi-touch devices. I'm in the process of building my own - great job with your project.


  13. wow !!! incredible its amazing when you touch the glass the finger tips was light to.. what a nice and unique idea .. how much it cost the glass ??

    led par 38

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