What it is

Tacchi is SigMusic's 46" fully multitouch table. Complete with 2 cameras and 4 lazers, Tacchi is capable of unlimited users. SigMusic first unveiled Tacchi at Engineering Open House in 2010, winning "Best Undergraduate Student Research" as well as the Lockheed Martin Computer Science Award. Tacchi was constructed over a period of 4 months, starting from commodity hardware components.

How it works

Tacchi works by the Laser Light Plane Illumination technique. More information can be found at the NUIGroup Wiki. Simply put: The lasers on top are ran through a line generator, turning them into a single plane of infrared light. By placing the plane just above the screen, your fingers interrupt it when you touch the screen. This lights up your fingers, which pass through the screen below, to the cameras. Since the cameras can only see infrared light, there is little interference from the backlight or other lights (But still some at all. Emergency floodlights tend to be problematic as well). Using simple and free software, we turn the camera feed into abstract TUIO coordinates, which can be passed to any application to use.

See it in action

Parts

Tacchi is constructed using the following:

• 46" LCD HDTV
• 2 Playstation Eye Cameras, with infrared filters
• 4 infrared lasers, with line generators
• Standard PC (quad core, 8gb ram)
• Acrylic Glass covering
• Custom casing (plywood, paint, elbow grease)

Construction

A full length discussion on the details of construction can be found elsewhere, but a simple explanation is as follows:

Step One

Separate the TV from the case, and the backlight from the LCD panel (They are both VERY fragile)

Step Two

Remove the IR Blocker from the webcams, replacing them with IR-Pass filters

Step Three

Assemble a box to put the LCD, backlight, lasers, and cameras

Step Four

Place Plexiglass on top of table, then place LCD on top of that. Mount Television components somewhere convenient, and place backlight near the bottom of the case (but leaving room for the computer)

Step Five

Place computer at the bottom of the case

Step Six

Place cameras on top of backlight

Step Seven

Mount lasers on top of the screen, just above the LCD

Step Eight

Finish construction of table

Step Nine

Install a TUIO Tracker, configure cameras

Step Ten

Write software on top of it!