// Comments
Jorn Loviscach
Fachbereich Elektrotechnik und Informatik
Currently there are many standard touch screens in use, but only very few multi-touch screens. Multi-touch offers many advantages to a single input, but comes at an increased cost. Standard touch screens are cheaper to manufacture and can be converted to a crude multi-touch screen.
The idea is that a touch screen consists of two layers of input, one for x and one for y. A current is passed through each layer, and the x, y position is determined by the resistance. Adding another input becomes a little more tricky. A voltage gradient must be applied to each layer to differentiate between different positions. Each layer is then combined to give the relative positions of each input. Due to the nature of the screen being in the x, y direction only, there can be no more than two separate inputs at a time.
By using resistance, a measure of pressure can also be determined. A pressure of 0.5 N must be applied to register for a single input. In testing, by using a pen tip, the sensed position is off by at most 5 pixels but when two points are used, the sensed position is off by at most 20 pixels with a fluctuation of 10 pixels.
Although the system does have limitations when compared to a conventional multi-touch screen, it still supports many different applications:
- Finger painting
- Selection
- Pan, zoom, rotation
- Rotary knobs
That's an interesting idea. It seems like this would be relatively easy to add to existing technologies. Additionally, since it doesn't require lots of extra hardware, it would be relatively inexpensive as well. I wonder how many multi-touch screens today are implemented this way.
ReplyDelete