TouchTable – General purpose smart table

I made a multipurpose transparent desk that has the ability to sense the hand and finger positions of anybody who touches it. This makes it a very interesting input device […]

I made a multipurpose transparent desk that has the ability to sense the hand and finger positions of anybody who touches it. This makes it a very interesting input device for your computer as it can act as your keyboard, sketch board, musical instrument, etc.

Explains the basic concept of Frustrated Total Internal Reflection

Explains the basic concept of Frustrated Total Internal Reflection

The sensing method is based on a technology called Frustrated Total Internal Reflection. Basically you flood a transparent piece of acrylic with IR light and then you place a camera with a visible light filter beneath it.

Shows the custom arrays of IR LEDs that I made and later attached to all edges of the acrylic

Shows the custom arrays of IR LEDs that I made and later attached to all edges of the acrylic

When anything is placed on the acrylic, it bends it slightly which changes the reflection properties and IR light “escapes” the acrylic. This is sensed by the camera.

The edges of the acrylic had to be filed down and polished using about 5-6 different types of sandpaper (going from rough to smooth)

The edges of the acrylic had to be filed down and polished using about 5-6 different types of sandpaper (going from rough to smooth)

When the camera has sensed the IR light in the acrylic, tracking it becomes a software problem. I used OpenCV for blob-tracking.

This image shows the legs that I retrieved from another desk. It also shows the mount for the camera in the center of the image

This image shows the legs that I retrieved from another desk. It also shows the mount for the camera in the center of the image

 

The finished desk

 

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