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Apologies if this is not the right place to ask this.

When I was in high school in the early 90s (maybe 1992 or so), they took us on a field trip to what I think was a government R&D center of some sort. One guy showed us an optical mouse which had a transparent window with "crosshairs" on it. I believe that it was used to "trace" drawings or schematics that were on paper, so as to digitize them, or maybe aid in the creation of new drawings (the same guy showed us a large color plotter). I have no idea to what kind of system it was all connected. They also had some pretty old stuff at that place, like those big reel tape drives and 8" floppies (already obsolete back then), but they seemed to be somewhat proud of the plotter, and the optical mouse was ahead of its time.

I remembered this the other day while watching a YouTube video about a very early optical mouse. I tried googling, but I couldn't find anything like what I saw. Do keep in mind that I was a kid back then, and this was some 25 years ago, so my memories are probably less than perfect. Considerably less.

Does anyone know of any mouse or device like that?

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    Welcome to Retrocomputing. Don't worry; this is the right place to ask. – wizzwizz4 Jan 27 '17 at 6:41
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    Did it look like anything found by googling "wacom lens cursor"? – Leo B. Jan 27 '17 at 8:27
  • @LeoB. Yes, it does look quite similar. Since I never saw one again, even working among graphic designers, I thought that it was some obscure and long-dead type of device. I'm surprised that they're still being made. – ironcito Jan 27 '17 at 19:16
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I think you are referring to what was back then called a digitizer. I believe they were mainly for CAD, but maybe someone who has experience with one could explain how they were used.

At first when I read your question I thought of the old optical mice (not opto-mechanical mice that had a mouse ball) that used a special mirrored mousepad with a grid. Sun workstations used these a lot, but they were also available on PCs.

  • Yes! That's it. I don't remember it having as many buttons as the ones that show up on a Google search, but it may have been a different model, or maybe I simply remember it differently than it was. That Mouse Systems optical mouse that you mention is precisely the one I saw in the video which made me remember this device. Thanks! – ironcito Jan 27 '17 at 19:06
  • Stock footage of a hand using a digitizer like the ones described here were in use for trade school commercials until the mid 2000s! – PhasedOut Jan 27 '17 at 21:47
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Graphics digitisers like this were not optical, they were magnetic.

Graphics Tablet

The tablet contained a grid of wires which encoded a small magnetic signal.
You moved either a stylus or, as you say, a device with cross-hairs over the tablet.
As you pressed a button on the stylus, it picked up the coordinates and fed them to the computer.
The coordinates could be picked up with great accuracy.

Apple made such a tablet for the Apple ][ and there were models for the HPIB.

I did see an optical model sold that had a row of LEDs along top and left edges, and detectors on the bottom and right. These passed into history quite quickly.

  • It's funny that I remembered it as an optical mouse, but it was neither optical nor a mouse ;) I'm glad to see that I wasn't too far off, though, as far as how it looked and what it was used for. Thanks for the info! – ironcito Jan 27 '17 at 19:11
  • They were also really good at erasing floppies accidentally placed on the digitizing surface … most of them had a warning label – scruss Sep 21 at 0:34
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Some of the early digitizers were off-line machines. In the 1970s We used to have one made by DMAC (sorry, I can't find a picture on the internet).

This was basically a stand-alone device the same size as a desk, with a glass top and the mechanism visible inside. The drawing to be digitized was taped to the glass. The operator used a device about the size of a modern computer mouse with a magnifying lens and cross hairs, that "sat" firmly on the paper to locate the points accurately (no wheels or rollers!), The coordinate were captured by pressing a button which punched the data onto paper tape for input to a computer. IIRC there was also a QUERTY keyboard to punch arbitrary data on the tape (e.g. identifying labels, etc).

The internal mechanism was basically a permanent magnet moving under the glass, connected to a pantograph arm and some position sensors. The permanent magnet tracked an electromagnet whose coil that was wound around the outside of the magnifying lens. If there was a large distance between the points being digitized, sometimes the two magnets lost contact with each other you had to search around a bit with the cursor until they "found each other" again. (It was easy to tell if the machine was still "following you" even when the drawing being digitized was obscuring the view, because the motors were quite noisy).

Despite the apparently crude mechanism, this was a high-precision device The specified accuracy was 0.1mm (0.004 inches) which was far better than the first "flat digitizing tablet" that replaced it.

The machine was also almost indestructible. On one occasion, an electrician decided to stand on top of it to change a light tube in the office, forgot that it wasn't a real desk, and instead of keeping his feet on the edges stood in the middle of the glass plate, shattered the glass, and fell into the mechanism. Having removed the electrician and the broken glass, we simply bought another sheet of glass from a hardware store, checked the accuracy of the machine (which was not affected!) and got back to work. Try doing that with modern computer equipment!

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