Topic: Transform a Regular LCD Into a Touchscreen (Page 1 of 1)

very interesting. its still a little bit expensive though. 100$, but it may become cheaper in near future. pity that i couldnt find a description how exactly this thing works...
http://hardware.slashdot.org/hardware/07/05/07/0210214.shtml

The Space Between Us | My Blog: lukas.grumet.at

A bit expensive? Nah, not if you've looked at the price of, say, a Cintiq tablet lately. $2400 vs. $100. $100 is cheap for this kinda tech. It's failings, though, include the fact that you don't have pressure control, and I don't know how accurate its tracking is. Mind you, for $100, those are *small* failings.


Justice 4 Pat Richard

Forgot to do that closing the URL tag thingy...

(Edited by Skaarjj on 05-09-2007 10:06)

Hey Mas, I think I can give you good idea of how it works...

I've used a white-board-and-projector type system before that makes use of both light and sound to track one of several pen sleeves (or a board wiper). The unit conected to a PC via USB 2.0, and allowed either the capture of real pen-work upon the board/screen, or the projection of virtual penwork using dummied sleeves.

The principal of the system is fairly simple; pens (or dummies) are inserted into a sleeve which emits a specific frequency of infrared and ultrasonic pulses. A passive sensor at the corner of the screen determines the angular position of the pen by detecting the infrared pulse, while the pen's distance from the sensor is determined by the time-lag between the light and sound pulses. The coordinates (so long as they fall within the pre-specified screen area) are then translated to the appropriate coordinates within the virtual workspace. The system is able to determine which pen is being used, and it is extremely accurate over the expanse of a white board or projection screen.

Of course, the system depends upon colour-specific battery-operated sleeves for each pen, but in principal, the same light-and-sound method could be applied on a smaller scale - and with any object used as a stylus, if the light and sound are emitted from an 'active' sensor unit and the reflections used to determine the position of the 'passive' object held close to the screen. The stylus would not be colour-specific in this case, but it would theoretically behave just like a touch-sensitive screen without pressure control.

If this system uses an accurate, miniaturised, active version of the above system, it's an absolute steal at that sort of price.

All theory here, of course...

EDIT: AHA! Not a passive stylus at all! I found the following line on their site:

quote:

---

Station
Receives ultrasonic and infrared signals from the digital pen.

---

So it works very much like the whiteboard system I've described above, and not a "touch-screen" at all. Happy me.

................
. ..............
........ .......
.............. .
................

(Edited by White Hawk on 05-08-2007 17:16)

mas: Just out of curiosity, what would you consider not expensive for something like this? 'Cause a hundred bucks sounds pretty cheap to me.


___________________________
Suho: www.liminality.org | Cell 270 | Sig Rotator | the Fellowship of Sup

I think the point was that cheap "for soemthing like this" and just plain "cheap" are two different things. While this might be economical in the big picture, $100 is still more than I'd spend on this...

FWIW

Well, that's true. But I have no frame of reference for this, being completely inept when it comes to drawing, so it sounded fairly cheap. What do you think something like this is actually worth?

The system I described is "eBeam". It's larger and likely far less accurate than its baby cousin, but retails from $749, according to the eBeam store.

I think that makes for an illuminating frame of reference.

................
. ..............
........ .......
.............. .
................