Low Budget TouchScreening ?

IntrepiD One writes: "I need to create an information gathering interface (preferably touchscreen) in a lobby area, but my budget is very low. I have looked at touchscreen add-ons (150-250 US$). Also, I want to create the interface in an X environment to add more flexibility. Before I go off and reinvent the wheel, does slashdot have any input." Any ideas for an inexpensive way to get input put in?

Thats very low budget...

[Bazman]

If you want to spend less than $200 then thats really low budget. I can only think that you'll have to get a trackball and make sure its bolted down, or behind glass or something.

Or if you can find a broken laptop computer with a working touchpad you could rip that out and mount it on the machine somehow. Users might have trouble working out how to move the mouse pointer with it though.

How complex is the UI going to be? If its down to simple menu choices you might be able to wire up a keypad or some buttons to a serial port.

By the way, $200 for a touch-sensitive screen overlay seems pretty cheap!

Baz

Low cost touchscreen

[gwizah]

Touchwindow [touchwindow.com] has low cost touchscreen systems that range from $140 for a 10.4" Check them out.

Re:Thats very low budget...

[schiller]

I have had good luck with an add-on touchscreen to an LCD display in a kiosk type of application. Depending on the size of screen you are planning to use, touchscreen overlays are available from $145 and up. Check out http://www.touchwindow.com. Good luck

Depending on your use

[tkrabec]

Use a Palm pilot or similar device you get a screen and a touch pad with a serial interface all in one

Another Idea

[New Breeze]

Our experience with the Touchscreen add-on's is that they are not very robust. Especially not for a public terminal. Get a touchscreen monitor, a good one. Other than that, if you feel like scrounging, try to find a POS (Point of Sale) systems vendor with some used terminal equipment. Most of these made in the last 4 years are touchscreen and Intel based.

Your lucky day

[Crypt0pimP]

Oddly enough, my father just bought out a storage unit that contained a few (total 10, 2 NIB) touchscreen CRT's. They're Elo touch screens, older model, 15" Drop me a line and I can give you more details, maybe arrange some testing. He's pretty hot to get rid of his inventory. BTW, anoyone want a cisco 1601 w/ T1 card? (was also in that storage unit.) address: slineyp at hotmail dot com. I am a private party, not a retailer or spam-meister.

What do you mean by cheap?

[human bean]

If you mean that you have more time than money, read on. Otherwise just buy the thing, and pay the price.

Consider making a grid of IR-LEDs (say top and left side)and photodiodes (bottom and right side). Build small adressing circuit run from parallel port of PC to individually strobe LEDs and see which detectors do not react. Software from there.

The venerable lightpen is even cheaper, has better resolution, and can be hacked together in moments.

Epoxy three piezoelectric tranducers (bottom left, top left, bottom right corners) on a monitor tube, attach to a/d circuit, have software monitor for vibrations from finger touch (yes, I know it can be done with only two sensors, but three makes the software much easier...)

If you can live with defined areas, get some thinly aluminiumised Mylar, form touch areas and circuits between them, then use those cheapie lamp controllers (60 cycle crossing detectors) to make data for parallel port.

I've never tried it, but I have observed change in capacitance in a monitor tube if you place your hand on it as the beam sweeps across. Build simple cap meter on front of A/D converter and then see if software can decipher changes in position.

All I can think of. Anybody else?

Re:What do you mean by cheap?

[cr0sh]

Great ideas - I would like to add that I have seen this sort of stuff done in VERY VERY old copies of Byte magazine, most notably in Ciacia's Circuit Cellar portion. If you have the skills and the time, you can do this cheap.

Worldcom [worldcom.com] - Generation Duh!

Time to get my walker shined up...

[human bean]

I have to admit it. By now I guess those back issues of Byte really are very, very, old.

*grumble*

I guess I better start hacking together assisted living gear. My wheelchair is gonna do the quarter mile in 13.8, drive itself in a thick fog, and provide a couple of hundred teraflops besides :-)

Really, _really_ cheap

[Manticore]

Ages ago I read a review for a touchscreen that basically consisted of a plate with strain gauges embedded at various points -- you sat the monitor on it and it could work out where you were prodding the screen by looking at how the force was affected for each gauge; I remember the reviewer being fairly astonished the thing worked at all. You needed to push harder than with normal touchscreens, and the resolution was pretty crude, but that's not such a bad thing for a kiosk application.

You could build something like this for virtually nothing (junk hardware, a few cheap components, and a spare joystick port.) It would take a fair bit of punishment too, and even if it was stolen or got broke you could easily build another. Of course doing the initial design and writing the drivers isn't going to be quick or easy, and you'll have to work around its limitations (I think frequent recallibrations were necessary) but TANSTAAFL.

IR Grid

[n0-0p]

I actually made the IR grid in high school for a C64. The library at my school had a book with that project and others like converting an IBM selectric typewriter to a printer and building your own plotter. Ah, the nostalgia. Anyway, the IR grid was pretty functional and easy to build and code, but I'm not sure how durable it would be in a permanent setup.

USB camera?

[Russ Nelson]

If this is for a kiosk, maybe you could put a USB camera at the top looking down at the monitor. You know what the screen *should* look like, because you have access to the screen contents. The difference is the person's hand. Pick the topmost occluded point, and that's the person's finger.
-russ

Re:Low cost touchscreen

[Ron Harwood]

Couldn't find the 10.4" - got a link?