Industrial Design Project Distant Bodies - 2 x FTIR 22" screens! 
Posted: 20 April 2009 04:45 PM   [ Ignore ]
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Hi all

I am a student at the faculty of industrial design at the Technical University of Eindhoven, the Netherlands. For our current project we are building 2 multitouch setups, to do research on creating awareness with multitouch.
It is our first projectweek, and we have been building for 3 days now. I find it interesting to see how other people build their screens, so I decided to share our building process as well.

Our goal is to design a new innovative communication platform, that creates a feeling of ‘awareness’ between users. For more info about this, you will have to wait wink it has only been 3 days!
Let’s hope this will be a succes and you will all be using our software in a few years… smile

We are making 2 identical screens at the same time! We have a lot of free materials at our school, like acryl, leds, wood, etc. In the workshop we can work with various tools, there is even a laser cutter available :D

We bought 140 x 940nm leds from a internetshop in holland, that only cost 6 cents each! Really cheap! LEDs-buy.nl

It is easyer for me to attach a few pictures per post, and describe what happens. So I will post some more in this topic soon!

Enjoy!

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LCD-FTIR in progress! xD

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Posted: 20 April 2009 04:54 PM   [ Ignore ]   [ # 1 ]
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the design

As you can see in the pictures, we made everything out of MDF and other cheap materials. These are freely available for us, so that is why we choose them.
We have 2 pieces of plexiglas, each 34 x 52 cm. We wanted to have an aspect ratio of 16:10, and this should be exactly that!
The plexiglas was cut with an industrial saw, the edges were really terrible!
We had to sand them with sanding paper, starting from 220, 320, 600 and eventually some polish to make them shine. This was really really an annoying job! With 3 people it took like an hour, and it still is not as clear as we would like it to be…

As you can see our drawings are not really secure, and we are creating the screens on the fly.

The LED holders are basically 2 MDF strips of 4 mm, because there was no MDF with a thickness of 8. So we glued 2 pieces together smile

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DPM12_002.jpg.jpgDPM12_003.jpg.jpgDPM12_004.jpg.jpgDPM12_005.jpg.jpgDPM12_006.jpg.jpgDPM12_001.jpg.jpg
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LCD-FTIR in progress! xD

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Posted: 20 April 2009 05:06 PM   [ Ignore ]   [ # 2 ]
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The LED strips

We have MDF strips of 8 mm thick, and 10 mm high. the LEDS are 5 mm in diameter each, and 8 mm long. They fit perfectly in the MDF!
Cutting the holes was boring, we used a standing drill (don’t know the exact word), and it takes time to drill 140 holes!

After this we fitted the LEDS inside the frames to see how it would look:

the other frame-parts are not so advanced so I won’t provide details about them (the supporting frames etc)

After placing all of the LEDS in the frame, we realised we forgot to place the mirror foil in place. We had to remove all the LEDS again!

The best way to cut holes in mirror foil was with a cool machine, that you can see in the picture. It’s like a big perforator!
After glueing the foil on the LED-frames, we cutted holes in them, and re-placed the LED’s in the frame.

As you can see the light can go into the acryl very nicely, and light is reflected back by the mirror foil.

And there is a very nice image of our supporting frame: it’s basically MDF plate that should hold the rest…

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LCD-FTIR in progress! xD

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Posted: 20 April 2009 05:18 PM   [ Ignore ]   [ # 3 ]
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The soldering

We never thought that soldering 140 LEDs was easy, but it was!
We have a 12 volt power supply, and lots of leds. After trying some schemes, we decided to make 28 parallel series of 4 or 5 leds. The reason why we choose these numbers will be explained later.

We had to connect groups of 5 leds together, and solder them together, and then make some wires on the right length..

And then solder all those wires to the groups of LED’s

We were making real progress and were almost ready to test! 1 side to go (4th image)

A quick and dirty broadboard circuit would provide the power that we needed… but it was really really a mess!

With all cables attached it was time to test. With our laptop and a modified webcam we could soon see that the lights were working!

We were running low on time, so after a quick test of the FTIR effect (which worked nicely!) we cleaned everything up.

Next week we are going to continue, so i’ll keep u updated on our progress. And later on our software progress offcourse!

PS: excuse for some blurry images. They are shot on an iPhone. And next time I will post more pics and describe them seperatly, instead of all together in a messy post.

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Posted: 20 April 2009 07:53 PM   [ Ignore ]   [ # 4 ]
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Hi sinnsyk,

Well I think that you have chosen bad wavelength LEDs, you should better get 850nm because of the sensitivity of the web cam.
Low quality grade web cams are very sensitive to 850-880nm and at 940nm the sensitivity is more the 4 times lower.

Having so much spare materials I hope your budget is bigger and finally you’ll go next week with little more expensive 850nm IR LEDs.

Keep up good work.

Cheers,

Goran

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Posted: 21 April 2009 08:29 AM   [ Ignore ]   [ # 5 ]
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Hi sinnsyk,

I like the way you’re using MDF smile Your progress looks very promising!

By the way, I’m also from the Netherlands and I’m also busy with my MT table.

Cheers,

-Nawid

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Posted: 23 April 2009 03:42 PM   [ Ignore ]   [ # 6 ]
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Today we continued on the project, and decided to redo the wiring. We made a stupid error, instead of making series of 6 led’s like the initial plan, we took series of 5.. The top frames hold 25 leds each, so devided by 5 would be better.. we thought.
Also, the side frames hold 8 leds each, so we made groups of 4 leds.

But, the resistors were like… HOT!

When u have 12 volts, just wire 6 leds in series. Don’t do stupid stuff like us rasberry

Anyway, we discovered that their was a much cleaner way of soldering, as you can see last pictures (see above) are very messy with wires everywhere, and the new setup is way cleaner.

We tested the leds with a modified infrared webcam, and the results were very very good! No issue with the 940 nm leds :D
We made a little test-board, with 1 of each led (850 and 940) and on all our camera’s they showed up the same brightness. So it won’t be an issue :D

You can see a picture of my laptop screen, where my fingers are very visible on the acryl. The FTIR effect works! You do have to push hard, but the silicone layer is going to be applied tomorrow.

Thanks for reading!

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LCD_dissasembly 127.jpgLCD_dissasembly 043.jpgLCD_dissasembly 018.jpgLCD_dissasembly 050.jpg
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