Touchscreens for LCDs (since I can't do a CRT-style light pen interface)

June 25, 2007 8:40 AM

TouchpanelFilter: Is it possible to order "bare" touchscreens without the logic?

I'm interested in developing large (in excess of 40") touchscreen overlays such as SmartTech's SmartBoard product (or to a lesser extent these overlays for laptops and flat-panel monitors.). But I don't need their logic electronics or their fancy software - I can handle all that on my own. I want the material with sandwiched capacitors that answer the question "where in X and Y did the user press?" in a length 'L' and width 'W.'

Basically I'm looking for the clear plastic sandwich that has an input for power and analog ouputs for pressure-sensitive positioning. Does anyone make anything like this ready to integrate into a frame with a microcontroller? Or do companies like SmartTech develop the technology on their own and guard it fiercely?

Thanks!

posted by ostranenie to media & arts (5 comments total)

I'm sure they're available. I don't know about in excess of 40", but this company sells the smaller sizes.
posted by wile e at 9:17 AM on June 25, 2007

Really? I couldn't find what I wanted on that site - they sell integrated touchscreen/monitors which are easy enough to find online, but I want the raw materials I can put a frame around and attach leads to my microcontroller unit from the analog sensors coming off the thing...
posted by ostranenie at 9:44 AM on June 25, 2007

Just google "large touchscreen" and you will find lots of suppliers. However you are not likely to find many simple capacitive or resistive touchscreen in the 40" size because it just isn't easy to manufacture or accurately sense the signals when you scale up to that size.

The more likely technologies for large touchscreens are surface acoustic wave and optical. Both of these have quite a bit more complicated interfaces.

This company seems to make large custom resistive touchscreens. Keep in mind that for large screens, the ITO layer must be thicker to keep the resistance to a reasonably low level. A thicker ITO layer means less light transmission so your display will be darker.

They also have scalable IR modules.

Unless you are buying in large quantities -- say hundreds of units -- you are not going to save any money by integrating your own electronics.
posted by JackFlash at 10:18 AM on June 25, 2007

I checked digikey and saw that 3M sold them in smaller sizes. To be honest, this sounds like something you may have to special order so you should just try calling a sales department. For instance, 3M shows their Cleartek and ToughTouch sensors, but doesn't specify size or cost, you must contact them by phone.
posted by Green With You at 10:18 AM on June 25, 2007

A buddy of mine at work also referred me to touchfoil, which also looks promising.
posted by ostranenie at 5:03 AM on August 27, 2007