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With the camera set up in the previous part I proceeded to IKEA in search of a suitable cabinet which I found a perfect one that has an open top (Its supposed to be for the kitchen, but it fit the purpose of a multi touch anyways :) )

Here is the IKEA code for the cabinet I bought:
IMG_6312

IMG_6315

The table with makeshift cardboard to hold the mini acrylic piece I got from Art Friends at Bras Basah Complex for around $8 SGD:
IMG_6319

The projector and materials in the cabinet, notice the cables running out from a small hole through the top, it was pretty convenient without having to manually drill a hole
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The first run of the initial set up:
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The blurry projection on about 40 pieces of laminating pockets as diffuser, acrylic at the bottom of those sheets
IMG_6331

Close up view from under the cabinet:
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In this iteration of the set up, there were basically loads of problems
– Hot spot from the IR illuminator
– Hot spot from the projector
– Floppy disk filter largely not effective (only discovered later on when the infrared cut filter arrived and made the magical difference)
– Double image from the standard mirror used (explained below)
– Lack of a proper holder to hold the mirror
– The laminating sheets were very poor diffusers

Explanation for double image:
In a standard mirror, there are two layers

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layer A is the glass layer and layer B is the reflective surface, because of refraction at the glass layer, some of the light slows and bends and causes another faint image to be projected beside the original image on the projection surface. The answer to this would be an industrial front surface mirror. These front surface mirrors are pretty fragile so special care has to be taken not to scratch its delicate surface.

Eventually the PS3 eye could not capture any blobs at all with the projector on. With the projector off, it was better and blobs could be registered. The PS3 eye is removed from its case and embedded in the makeshift Styrofoam holder (which is bad as I found out later on because the camera sat on the projector and the Styrofoam basically hits everything up a lot and caused the projector to overheat and shut down automatically after just 3 - 5 minutes)

These are the equipments I used above
- 1 x Sanyo PLC-XW60
- 1 x IR illuminator (domed shape, 180 degrees illumination, bought from Jia Ying at Sim Lim Square)
- 1 x normal mirror from IKEA (they don't sell single pieces, but set of 4s)
- 1 x PS3 Eye modified with floppy disk visible light filter
- 1 x Frosted acrylic from Art Friends
- Many pieces of laminating sheets
- 1 x cabinet
- 1 x multi plug extension
- 1 x Sony TZ notebook

  • not in the list but it helps to have a wireless mouse/keyboard

More to come in part 3..

  • I have managed to create the working table and a video of which is available at youtube
    Video of the completed table running demo from touchlib:
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