Early Touch Screen Technology 1982 - Page 1
Forum section: electronics / general

author: Nusa
author_rank: Super Contributor
timestamp: April 09, 2017, 08:30:02 pm
content: Same technology, 10 years earlier, was on Plato IV terminals:http://knkx.org/post/timeline-history-touch-screen-technology

author: vk6zgo
author_rank: Super Contributor
timestamp: April 10, 2017, 05:00:32 am
content: Tektronix had it on TV waveform monitors in the mid 1990sA silly application, really, because if someone puts his finger on the quite small screen, to point out a waveform anomaly, the stupid thing changes from line rate display to frame rate, or vice versa.

author: james_s
author_rank: Super Contributor
timestamp: April 10, 2017, 05:08:58 am
content: Touchscreens were stupid then and they're stupid now. They work well on smartphones and tablets due to the constraints of requiring a complex user interface on a pocket sized device but for practically everything else I hate the things. They never seem to respond properly to my fingers, same with capacitive touch buttons. I end up mashing the thing repeatedly until it finally picks up my touch.

author: helius
author_rank: Super Contributor
timestamp: April 10, 2017, 05:56:44 am
content: Resistive touch sensors are pressure-sensitive. With the other types, mashing doesn't do anything.

author: james_s
author_rank: Super Contributor
timestamp: April 10, 2017, 03:17:47 pm
content: Well it does something for me. These are capacitive touch buttons on one of the products my company made, and the capacitive touchscreens on the ATMs my bank uses. I'll touch the button/screen several times and it does nothing, then I tap harder and harder, and eventually it picks up one of my taps. Multiple devices, not just one.

author: helius
author_rank: Super Contributor
timestamp: April 10, 2017, 07:58:12 pm
content: I've had the issue with bank ATMs not registering a tap. I think the issue is in the computer software dropping events, not the sensor. So it's not pressing harder that makes it work, it's conforming to the profile that it's able to "see" (contact area and time difference between on/off)

author: james_s
author_rank: Super Contributor
timestamp: April 10, 2017, 09:10:48 pm
content: I don't know if it's pressing harder, or more often or over a larger area or what, but I end up tapping repeatedly and it tends to get harder just out of frustration whether the force has any impact or not. I do suspect it does increase the capacitive coupling though, skin is flexible and the harder you press, the larger the contact patch to some degree. Either way most touch interfaces strike me as unreliable and cumbersome, with no tactile feedback. Unfortunately they are trendy.

author: coppice
author_rank: Super Contributor
timestamp: April 10, 2017, 09:22:58 pm
content: I used to use that very terminal. I can't remember who made them. We had three types of terminal, which all looked the same from the outside - a straightforward VT100 clone; the VT100 clone with added Tek 4010 emulating graphics; and the one in the video, which added touch sensing.

author: coppice
author_rank: Super Contributor
timestamp: April 10, 2017, 09:32:08 pm
content: Quote from: helius on April 10, 2017, 05:56:44 amSome approaches to capacitive touch can sense pressure. Crudely this can be done by detecting the variation as more of the skin is squashed against the panel. However it is possible to go beyond that with the right sensing technique.There have been several touch techniques which produce a pressure sensitive response. For example, using ultrasonic sensing - where a surface wave is pinged in the X and the Y directions, and echoes are detected - produces echoes whose strength varies with the applied pressure. I was also told that a modern derivative of the infra red beam technique shown in the video, which is used in e-paper e-book readers and other applications, is also capable to detecting pressure, but I don't know how that works. Perhaps it is used a matter of the finger spreading out and interrupting more beams.

author: helius
author_rank: Super Contributor
timestamp: April 10, 2017, 09:40:39 pm
content: Any touch technology can be augmented with pressure: just mount the whole thing in an elastic bumper and measure its deflection from zero...Not as silly as it sounds. Many music keyboards with channel (not key) pressure do it that way.

author: rfeecs
author_rank: Frequent Contributor
timestamp: April 10, 2017, 09:46:40 pm
content: This same infra-red touch screen technology was used in the HP-150, introduced in 1983:

author: johnboxall
author_rank: Unknown
timestamp: April 10, 2017, 10:16:39 pm
content: We had that touch-screen on the Xerox 5100. Evil bastard of a machine.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: April 10, 2017, 11:27:40 pm
content: Quote from: tronixstuff on April 10, 2017, 10:16:39 pmUsed to love that machine. Did lots of engineering proposals on that thing, copying bits and pieces of various things into something that looked viable. Didn't have access to meaningful CAD at that time and drafting was at best slow for me (either done myself or farmed out to the pros), but with the scaled copy feature, scissors and scotch tape magic could happen in just a couple of hours.

author: DrGeoff
author_rank: Frequent Contributor
timestamp: April 11, 2017, 12:09:58 am
content: Remember the Fairlight CMI?It had a touch screen that you used a stylus to draw the waveform and harmonics.Incredible stuff with the technology available prior to 1979.

author: xrunner
author_rank: Super Contributor
timestamp: April 11, 2017, 12:14:22 am
content: Quote from: james_s on April 10, 2017, 05:08:58 amYea. A mouse is better then putting your hand in front of the screen except as you say when it's a small phone or the like.The other thing is, I can't stand finger smudgy smears on my screen.

author: james_s
author_rank: Super Contributor
timestamp: April 11, 2017, 12:51:18 am
content: Same here, I can't stand it when somebody walks up and points out something on my screen and leaves a finger smudge, arg!

author: android
author_rank: Regular Contributor
timestamp: April 11, 2017, 09:58:37 am
content: Quote from: james_s on April 11, 2017, 12:51:18 am+1IMHO, if you must engage in gerfingerpoken, it is polite to rotate your digit and make contact with just your fingernail.

author: james_s
author_rank: Super Contributor
timestamp: April 11, 2017, 05:29:11 pm
content: Or just point from an inch or two away, it's not often that one needs to point with single pixel precision.

author: Rick Law
author_rank: Super Contributor
timestamp: April 12, 2017, 03:26:55 am
content: Quote from: Nusa on April 09, 2017, 08:30:02 pmGood old PLATO!Not just touch-screen equipped. That PLATO terminal pictured in the article (with extra thick top) looks like it was also equipped with slide projector capable of projecting an actual film slide image super-imposed to the computer display. That orange plasma screen was mesmerizing to look at. 512x512 (monochrome), touch-grid resolution is only 32x32. The PLATO terminal was tied to a Control Data Corp back-end Cyber (60 bits) mainframe.The first "on-line" dating resulting with a marriage (that I was aware of) was in 1981+-1 on this PLATO system. Both were students at U of Delaware, met on-line (more precisely, met on PLATO), get to know each other on PLATO, arranged dates on PLATO. later married around 1981. The groom was my friend whom I met a few years earlier on PLATO. I was invited to the wedding by PLATO "p-note" (email to you folks).The article just mentioned University of Illinois used it. While U of Illinois was "home base" to PLATO, many other education institutions used it. Many businesses used it too (for training/education) back then. It was possibly the most prolific touch screen terminal back then in 1970/80's.

author: noidea
author_rank: Unknown
timestamp: April 12, 2017, 04:15:22 am
content: Quote from: rfeecs on April 10, 2017, 09:46:40 pmAah that brings back memories, my parents had one to run the accounting software for my fathers business. I remember that they hardly ever used the thermal printer on the top, there was a separate dot matrix connected to print out the invoicesPlaying games was strictly verboten...but they did buy us a Apple IIe clone for that

author: Nusa
author_rank: Super Contributor
timestamp: April 12, 2017, 05:53:41 am
content: Quote from: Rick Law on April 12, 2017, 03:26:55 amCorrect. That sliding door in the top section was for inserting the microfiche for rear projection on the plasma screen. The mechanism was pneumatic and required an external air source to operate, which usually was only provided in classrooms that used the feature. Many people exposed to Plato never saw that feature in operation, and it wasn't kept in later terminal designs.The plasma displays were new tech, and amazingly reliable. 512x512 was a fantastic resolution for 1972, a day when most computer terminals were text-based. Remember, this was nearly 10 years before the IBM PC launched with CGA resolution (640x200 2-color mode, 320x200 4-color mode). EGA (640x350 16-colors) didn't happen until 1984. It wasn't until VGA in 1987 that you had a PC with comparable resolution.The infrared touch screen was actually only 16x16 then (see the grid in the picture...that's actually a prototype touch panel), but good enough to make selections on-screen. They could be tempermental because dust tended to gather on the bottom-side sensors. Blowing the dust off regularly was required. This was before computer mice were a thing, so it was a useful alternative to the keyboard input.

author: Rick Law
author_rank: Super Contributor
timestamp: April 12, 2017, 05:30:47 pm
content: Quote from: Nusa on April 12, 2017, 05:53:41 amYeah, and the pneumatic mechanism shakes the whole table when moving/stopping rapidly (during slide selection).I recalled walking into U of Illinois CERL (Computer-based Education Research Lab) PLATO room and some guys were chuckling/laughing...A very naughty fellow wrote something very naughty, and thatnaughty program used the slide projector to make movements to shakethe whole thing - to match the action displayed on the screen. (One can imagine the exact naughty thing that the naughty fellow wrote.)The later "IST" terminals made by Control Data with a CRT really doesn't have the magic of the plasma PLATO terminals. That said, the IST's 8080 CPU was fun to play with. For that time frame, there really was very few systems that came near in terms of capability.Now this conversation makes me want a good game ofEmpireorDND....Empire: 30 players Star Trek like space war gameDND: single player Dungeons and Dragons find treasure fight monsters game

author: mmagin
author_rank: Frequent Contributor
timestamp: April 12, 2017, 10:04:10 pm
content: Quote from: DrGeoff on April 11, 2017, 12:09:58 amI've always been amused by the elegant simplicity of light pens (or similar things like the gun controllers for arcade games and the NES). Just a reasonably fast-responding photodiode/transistor, optics if it's not used right against the screen, some combination of hardware/software to measure the time from vertical retrace to the signal on the light pen.

author: james_s
author_rank: Super Contributor
timestamp: April 12, 2017, 11:11:32 pm
content: Yeah those light pens and light guns are pretty cool. Because of the way they work, they will only work on a raster scan CRT display, otherwise they have no way of identifying where they are pointed.

author: helius
author_rank: Super Contributor
timestamp: April 13, 2017, 01:27:15 am
content: I believe this was mentioned here once before: vector CRT displays are also capable, in principle, of using light pens. The Sketchpad system from 1963 used a light pen to select objects on a vector display. It is true that registering the input is somewhat more complicated; you also cannot select empty space (since there is no raster).Edit: The SAGE situation display terminal (circa 1958) also used a vector display (with Charactron!) and had a light gun to select targets (with a pistol grip, and a rubber point to hold the optics the proper distance from the screen).

author: james_s
author_rank: Super Contributor
timestamp: April 13, 2017, 01:31:37 am
content: Well the technology could be used with a vector display, at least to some extent, but the video games and light pens out there designed for raster displays will only work with a raster display, that's what I meant. I suppose I should have just said CRT display and not mentioned the raster part.

author: coppice
author_rank: Super Contributor
timestamp: April 13, 2017, 01:58:23 am
content: Quote from: helius on April 13, 2017, 01:27:15 amWe used to use light pens with vector scanned displayed, but we only needed to pick out things which were being displayed, and so were lit up. I did see others using light pens to pick any spot on the display by using a quick flash of a complete raster sweep, boustrophedonic style. The resulting flash was rather annoying, though.