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tingo
September 3rd, 2009, 11:57 AM
I'm not really sure if this is the right forum, but I'll take my chances.

Has anyone tried to use a web camera (or other computer-connected camera) as an optical reader for (computer) paper tapes?

Chuck(G)
September 3rd, 2009, 12:26 PM
I don't know why it wouldn't work, but it would seem to be slow, given that you'd need to get a complete frame scanned before moving the tape.

Give me a bunch of photodiodes any day.

tingo
September 3rd, 2009, 12:39 PM
Well, most webcams (on modern machines at least) can easily do 10 - 15 frames per second I think, so the acquisition part should be fast enough. To mke the image processing fast enough, just ditch all but one of equal images. I am thinking of using a "slot" (for lack of a better word) to feed the paper tape through. This slot would be sized so that only one row of the paper tape would show at any time, this would simplify the image processing even more.

Chuck(G)
September 3rd, 2009, 01:11 PM
By contrast, a vintage PT optical reader can do in excess of 1000 cps.

But your method should work, even if it sounds harder.

Ole Juul
September 3rd, 2009, 02:38 PM
First off I should say that I have no experience with paper tape, but I do think that Chuck(G) is right about photo diodes. Surely that solution is both cheap and trivial to implement. I would think that the software would require much more work than a simple reader. Of course, many computer people shy away from even simple circuitry and would rather program their way out of a problem. Fair enough. In that case, why not use an optical mouse? I've seen them used as scanners. Just an idea. :p

Chuck(G)
September 3rd, 2009, 03:04 PM
The nice thing about a photodiode array is that the sprocket holes can be used to generate clock pulses. Then the speed becomes a matter of how fast you can pull the tape. No intelligence required.

NeXT
September 3rd, 2009, 04:50 PM
Can you still get photodiodes? I checked my local electronics supplier and he has not seen them in ages.

Chuck(G)
September 3rd, 2009, 06:23 PM
Can you still get photodiodes? I checked my local electronics supplier and he has not seen them in ages.

Has he ever heard of a CD-ROM or DVD drive? I wonder what they use as detectors? Them new-fangled fiber-optic networks, it seems to me use PIN photodiodes.

If he needs a resource, tell him to contact Hamamatsu sales (http://sales.hamamatsu.com/assets/html/ssd/si-photodiode/index.htm).

You could also use phototransistors. Even an LED will serve as an adequate photodiode in a pinch--and I think they're still made... :p

Ole Juul
September 3rd, 2009, 10:15 PM
All the regular Vancouver retail electronics parts shops carry a selection: Main, Lee's, and of course RP (now in Burnaby).

tingo
September 4th, 2009, 09:15 AM
I don't know why it wouldn't work, but it would seem to be slow, given that you'd need to get a complete frame scanned before moving the tape.

Give me a bunch of photodiodes any day.

Well, I'm trying to work with what I got (or can get without to much hassle and within an acceptable price range), and photo diodes that can work for a paper tape reader seems to be hard to get here.

tingo
September 4th, 2009, 09:21 AM
Fair enough. In that case, why not use an optical mouse? I've seen them used as scanners. Just an idea. :p
Interesting. Do you have any references to such projects?
What kind of optical sensor sits in an optical mouse? (A bit later) Interesting, it seems that optical mice uses image processing, so the electronics would be suitable for this task, if it is possibøe to get it to work the way I want.

Later: Ok, I found this: Optical Mouse Cam (http://www.bidouille.org/hack/mousecam/) and Sprites Optical mouse-cam (http://spritesmods.com/?art=mouseeye). I have an old optical mouse with the A2051 chip. But based on the results of those tests I'm not certain that this will work.

Chuck(G)
September 4th, 2009, 01:45 PM
Another possibility might be the sensor from a flatbed scanner, particularly one that can also scan 35 mm slides or negatives.

cosam
September 4th, 2009, 01:58 PM
How about a bunch of good old-fashioned ball mice? Each contains at least two light-sensitive components of some kind, and you get the matching IR light source for free ;-)

Ole Juul
September 4th, 2009, 01:59 PM
I saw the mouse scanner on endgadet but the link is dead. I believe the second link you posted is to the same project. Ya, maybe it's not such a brilliant idea for this purpose. :( Regarding photodiodes, there's always mailorder. Some places don't mind small orders and the shipping cost is minimal on such small parts.

EDIT: I just noticed that cosam has what is indeed an excellent idea. I'd like to see some of those old ball mice put to good use. :)

Chuck(G)
September 4th, 2009, 03:50 PM
You realize, of course, if you wanted to keep this thing completely vintage, you wouldn't wimp out with any of that solid-state stuff--you'd use an array of vacuum phototubes (still made by Hamamatsu):

http://parts.usbid.com/photos_wm/8F/8F15AD49A16847E0878789C4CF2FFE70.jpg

MikeS
September 4th, 2009, 08:59 PM
I'd vote for the sensor from an old flatbed scanner as Chuck suggested.

May I ask what you're planning to read with this gizmo?

NathanAllan
September 4th, 2009, 09:30 PM
I think I can get vintage tubes if you want to go that route. My buddy Joe (and me for that matter) have a lot of tubes that really have nothing to do.

Ole Juul
September 4th, 2009, 10:39 PM
I think I can get vintage tubes if you want to go that route. My buddy Joe (and me for that matter) have a lot of tubes that really have nothing to do.
Phototubes?

NathanAllan
September 5th, 2009, 07:32 AM
Phototubes?
Let me know a number off one, I'll see. Most of these are audio/power related but some were multi purpose.

Chuck(G)
September 5th, 2009, 10:41 AM
Let me know a number off one, I'll see. Most of these are audio/power related but some were multi purpose.

1P39 or 939 (same tube, one has a low-loss base).

NathanAllan
September 5th, 2009, 09:22 PM
1P39 or 939 (same tube, one has a low-loss base).
I'll check, see what is here. Boxes to look in, not that I'm complaining, I love going through this stuff.

tingo
September 6th, 2009, 02:14 PM
You realize, of course, if you wanted to keep this thing completely vintage, you wouldn't wimp out with any of that solid-state stuff--you'd use an array of vacuum phototubes (still made by Hamamatsu):

http://parts.usbid.com/photos_wm/8F/8F15AD49A16847E0878789C4CF2FFE70.jpg

And how do you suggest to mount those phototubes so that eight (nine actually, with the sprocket) will fit the width of a paper tape?
:-)

tingo
September 6th, 2009, 02:17 PM
I'd vote for the sensor from an old flatbed scanner as Chuck suggested.

May I ask what you're planning to read with this gizmo?

I thought I mentioned that in the first post: Paper tape (http://en.wikipedia.org/wiki/Paper_tape), aka punched tape.

tingo
September 6th, 2009, 02:29 PM
Another possibility might be the sensor from a flatbed scanner, particularly one that can also scan 35 mm slides or negatives.

Aren't flatbed scanner using ccd's just like digital cameras?
What would make a scanner better suited?

Chuck(G)
September 6th, 2009, 03:34 PM
And how do you suggest to mount those phototubes so that eight (nine actually, with the sprocket) will fit the width of a paper tape?
:-)

Optics, lad, optics. A bit o' fiber optic magic might work wonders.

dave_m
September 6th, 2009, 07:56 PM
Chuck,
I knew you had an answer to that question, but mixing vacuum phototubes and fiber optics! Now that's either genius 'out of the box' thinking or maybe we should call the guys in the white outfits from the funny farm to come pick you up. :)
-Dave

MikeS
September 6th, 2009, 08:24 PM
I thought I mentioned that in the first post: Paper tape (http://en.wikipedia.org/wiki/Paper_tape), aka punched tape.
Smart ass!

What's *ON* those paper tapes?

Sheesh...

Chuck(G)
September 6th, 2009, 08:42 PM
Chuck,
I knew you had an answer to that question, but mixing vacuum phototubes and fiber optics! Now that's either genius 'out of the box' thinking or maybe we should call the guys in the white outfits from the funny farm to come pick you up. :)

It wouldn't need to be fiber necessarily. you could use glass rods or mirrors.

How about this? A spinning mirror and a single photocell that scans the width of the tape? Come to think of it, why couldn't you modify a supermarket barcode scanner?

You could also do the job with vacuum switches that are activated as the tape is passed over a perforated plate, player-piano style.

MikeS
September 6th, 2009, 08:49 PM
It wouldn't need to be fiber necessarily. you could use glass rods or mirrors.

How about this? A spinning mirror and a single photocell that scans the width of the tape? Come to think of it, why couldn't you modify a supermarket barcode scanner?

You could also do the job with vacuum switches that are activated as the tape is passed over a perforated plate, player-piano style.
... or little wire brushes like the unit record punched card readers...

I used to have one that pushed little pins up through the tape; the pins were linked to interposer bails on a mechanical keyboard and effectively "pressed" the corresponding keys.

But I prefer the simplicity of my various optical readers; a light bulb on top, a 9-element photo sensor and a driver IC/transistor array. And a motor to move the tape of course.

dave_m
September 7th, 2009, 09:08 AM
But I prefer the simplicity of my various optical readers; a light bulb on top, a 9-element photo sensor and a driver IC/transistor array. And a motor to move the tape of course.

A bit of trivia. I once attended a Data General NOVA minicomputer training class for new users and the instructor mentioned that the light source on their paper tape reader was a VW brake light bulb. He said they tested it and found it produced a very consistent light output.

tingo
September 8th, 2009, 01:16 PM
Smart ass!

What's *ON* those paper tapes?

Sheesh...

Smart ass yourself.
Computer programs (and source code), in this case from an old 16-bit computer from an old Norwegian company. Thiunk before Norsk Data.

Sheesh ... some people doesn't even know how to ask questions properly,

:-)

MikeS
September 8th, 2009, 07:37 PM
Smart ass yourself.
Computer programs (and source code), in this case from an old 16-bit computer from an old Norwegian company. Thiunk before Norsk Data.

Sheesh ... some people doesn't even know how to ask questions properly,

:-)
Well, when someone asks what you want to read with your paper tape reader, answering "paper tape" does sound a little, umm, smart-assish...

And I had even sort of assumed that the tapes contained computer programs or data of some kind...

MikeS
September 8th, 2009, 07:42 PM
A bit of trivia. I once attended a Data General NOVA minicomputer training class for new users and the instructor mentioned that the light source on their paper tape reader was a VW brake light bulb. He said they tested it and found it produced a very consistent light output.
Not unusual; several of my PPT readers use a standard 12V single-filament automotive bulb and it doesn't seem to be very critical at all.

linuxlove
September 9th, 2009, 10:34 AM
anyone got any schematics for making your own papertape reader? or is this a very complicated project and schematics don't exist for it?

NathanAllan
September 9th, 2009, 01:50 PM
little update about tubes: I don't have any of those in the boxes and they're running about $30 each nowadays. I was shocked on both counts.

I'd also like to learn about making a paper tape reader or maybe a writer (hole puncher, I know). Now that I'm thinking about it (might be the fever talking) that would make an excellent encryption method; if everything is on physical media like paper tapes it would be time consuming and very impractical to try to steal.

Ole Juul
September 9th, 2009, 03:22 PM
OT:

little update about tubes: I don't have any of those in the boxes and they're running about $30 each nowadays. I was shocked on both counts.
I had a similar shock about 30 years ago. I had bought an amp which didn't have the tubes and they wanted about 50 bucks for a used set. These were common and previously cheap tubes and in a store that wasn't gouging.


I'd also like to learn about making a paper tape reader or maybe a writer (hole puncher, I know). Now that I'm thinking about it (might be the fever talking) that would make an excellent encryption method; if everything is on physical media like paper tapes it would be time consuming and very impractical to try to steal.Don't fool yourself on the encryption. My second wife had trained as a teletype operator and she could read the tape visually. That was in Japan and apparently all operators were taught that skill. I assume it was the same here. You can't win! Probably the best way to hide stuff is to write it with vinegar on a hard boiled egg. lol

dave_m
September 9th, 2009, 03:28 PM
anyone got any schematics for making your own papertape reader?

Someone is selling a new reader on ebay for quite a bit of money. But it will give you an idea of the simple circuitry.

tape reader on ebay (http://cgi.ebay.com/Paper-Tape-Reader-for-S-100-SOL-20-and-other-vintage_W0QQitemZ150371363013QQcmdZViewItemQQptZLH _DefaultDomain_0?hash=item2302d4e8c5&_trksid=p3286.c0.m14)

dave_m
September 9th, 2009, 03:33 PM
I'd also like to learn about making a paper tape reader or maybe a writer (hole puncher, I know).

Here's a paper tape punch on ebay (pretty imposing looking gadget):

Paper tape punch (http://cgi.ebay.com/Tally-P150-P-150-High-Speed-Paper-Tape-Punch_W0QQitemZ190124561538QQcmdZViewItemQQptZLH_D efaultDomain_0?hash=item2c444e9482&_trksid=p3911.c0.m14)

NathanAllan
September 9th, 2009, 09:36 PM
General Dynamics, nice. I meant encryption past the codes themselves, not paper tape as an encryption method. I think that was the fever kicking when I said that.

MikeS
September 10th, 2009, 02:40 PM
Someone is selling a new reader on ebay for quite a bit of money. But it will give you an idea of the simple circuitry.

tape reader on ebay (http://cgi.ebay.com/Paper-Tape-Reader-for-S-100-SOL-20-and-other-vintage_W0QQitemZ150371363013QQcmdZViewItemQQptZLH _DefaultDomain_0?hash=item2302d4e8c5&_trksid=p3286.c0.m14)
Whooeee... I remember those being a lot cheaper...

I've got a few PPT readers (motor driven at that), and the price just went up substantially ;-)

Actually, the basic circuitry is a lot simpler than that; the critical part of course is the 9-position photo sensor; run that into a transistor array or a couple of Schmitt trigger driver ICs using the feed hole for a clock and that's usually all you need.

MikeS
September 10th, 2009, 02:48 PM
Here's a paper tape punch on ebay (pretty imposing looking gadget):

Paper tape punch (http://cgi.ebay.com/Tally-P150-P-150-High-Speed-Paper-Tape-Punch_W0QQitemZ190124561538QQcmdZViewItemQQptZLH_D efaultDomain_0?hash=item2c444e9482&_trksid=p3911.c0.m14)

I've got a few punches (perforators actually) as well, but nothing quite as fast as that one; looks like it might be a bit of a challenge to interface though.

Unlike the readers, perfs are obviously much more complex mechanically and thus also usually much heavier; can't really pull the tape through by hand very well although I do seem to recall seeing a manual punch a looong time ago (I do have a manual 80-column card punch though, and it even prints on the card!)

I've scrapped a few in my time and have some parts like punch blocks, feed wheels etc., but I can't really imagine building one from scratch even with the crucial parts...

MikeS
September 10th, 2009, 03:23 PM
Here's the original Oliver Audio reader that the one on ebay is based on:

http://www.swtpc.com/mholley/OAE80_Reader/OAE80_Index.htm

And here's an old Byte article about building your own:

http://www.classiccmp.org/cini/pdf/byte/manual_ptp.pdf

If I were building one I'd add a UART and RS-232 driver and output serial data; then you wouldn't need any special software on the computer side.

dave_m
September 10th, 2009, 03:25 PM
Actually, the basic circuitry is a lot simpler than that; the critical part of course is the 9-position photo sensor; run that into a transistor array or a couple of Schmitt trigger driver ICs using the feed hole for a clock and that's usually all you need.

Is a schmitt trigger enough to de-glitch the photo sensors? I would also add a de-bounce latch circuit on at least the sensor on the sprocket hole (clock). Now let's figure out how to add a stepper motor so we won't wear ourselves out pulling the tape across the sensors. :)

MikeS
September 10th, 2009, 03:38 PM
Is a schmitt trigger enough to de-glitch the photo sensors? I would also add a de-bounce latch circuit on at least the sensor on the sprocket hole (clock). Now let's figure out how to add a stepper motor so we won't wear ourselves out pulling the tape across the sensors. :)
Can't hurt to condition the signals but you could also do a pretty good job in the reading software; mind you, if you did add a UART to turn it into a serial device then you probably would have trouble with the odd fuzzy hole or dust.

Don't even need the complication of a stepper. Most of mine just use an ordinary AC motor like an old turntable or fan motor; matter of fact, the SCM units do have a cooling fan blade on the end of the drive motor (geared down a bit for the drive sprocket of course).

tingo
September 10th, 2009, 03:39 PM
Well, when someone asks what you want to read with your paper tape reader, answering "paper tape" does sound a little, umm, smart-assish...
Maybe it' is because english isn't my native language, but I didn't read that in your question at all. The discussion had strayed a bit, and you did ask "what you're planning to read with this gizmo?" instead of "paper tape reader".

Sorry if you confused me so I confused you.

tingo
September 10th, 2009, 03:44 PM
Someone is selling a new reader on ebay for quite a bit of money. But it will give you an idea of the simple circuitry.
I can't help thinking that he would sell a lot more of them if the price was 25 bucks instead.....

dave_m
September 10th, 2009, 03:45 PM
And here's an old Byte article about building your own:

http://www.classiccmp.org/cini/pdf/byte/manual_ptp.pdf



How I miss Byte Magazine! Did you know that you can till read monthly articles about Jerry Pournelle's trial and tribulations with getting things to work on his PC? The guy is a good writer but has never learned how a computer works.

Jerry Pournelle (http://www.chaosmanorreviews.com/)

MikeS
September 10th, 2009, 03:59 PM
Maybe it' is because english isn't my native language, but I didn't read that in your question at all. The discussion had strayed a bit, and you did ask "what you're planning to read with this gizmo?" instead of "paper tape reader".

Sorry if you confused me so I confused you.
Yeah, the way these things drift off-topic I can understand that and maybe shouldn't have assumed that the "web camera as a paper tape reader" header would make it obvious what I meant by "gizmo."

But I was just teasing you with my "smart ass" comment and hope you didn't take it seriously (or, if you did, that you don't now); I have heard that due to the cold climate Norwegians have even less of a sense of humour than Canadians, but that's not true is it?

The reason I asked was in case you were primarily concerned with reading the tapes (instead of building a camera-based reader) then there are folks around who could do that for you, especially if they were of general interest (outside of Norway that is ;-) )

MikeS
September 10th, 2009, 04:04 PM
How I miss Byte Magazine! Did you know that you can till read monthly articles about Jerry Pournelle's trial and tribulations with getting things to work on his PC? The guy is a good writer but has never learned how a computer works.

Jerry Pournelle (http://www.chaosmanorreviews.com/)
Cool! I didn't know that Chaos Manor was still around; it usually provided a (probably unintentional) chuckle in every issue and "Real Soon Now" long ago became an oft-used-since part of my vocabulary.

MikeS
September 10th, 2009, 04:05 PM
I can't help thinking that he would sell a lot more of them if the price was 25 bucks instead.....
Sounds like an opportunity; parts couldn't cost much more, if that.

dave_m
September 10th, 2009, 04:18 PM
I can't help thinking that he would sell a lot more of them if the price was 25 bucks instead.....

Yes, I agree. But there can not be a very big market for tape readers. However, if I had an old computer with a big pile of tapes, I might want one of those but at that price I would build a "kludge" (a quick & ugly home made version). Mike and I can help you get one to work.
-Dave

MikeS
September 10th, 2009, 04:31 PM
Yes, I agree. But there can not be a very big market for tape readers. However, if I had an old computer with a big pile of tapes, I might want one of those but at that price I would build a "kludge" (a quick & ugly home made version). Mike and I can help you get one to work.
-Dave
Hmm, this discussion is starting to motivate me to whip up an interface for one of the perforators so I can actually punch some tapes; I threw out boxes of tapes back when old computers were just junk and now there are only two or three that missed the purge left to play with.

We used to also "print" banners of text along the tape using the holes like a dot matrix printer; great for birthday and anniversary parties, especially with coloured tape (and the chad was for weddings of course). Many of the old system tapes did that as well to label the tapes instead of just writing or sticking labels on them.

dave_m
September 10th, 2009, 04:55 PM
Can't hurt to condition the signals but you could also do a pretty good job in the reading software; mind you, if you did add a UART to turn it into a serial device then you probably would have trouble with the odd fuzzy hole or dust.


I don't remember too much about paper tape data formats. Was there a parity bit on each row of data or were there sumcheck words at the end? I hope you did not have to verify the data by running the tape through a second time?

Chuck(G)
September 10th, 2009, 06:05 PM
Most computer-oriented paper tapes of the 60's and later were 8 channel. The 8th channel was normally used for parity, unless binary was being punched.

However, paper tape was used on a lot of gear, from early CNC to telegrams. Tape using 5 level Baudot encoding was used for a very long time. There are also 6 and 7 level paper tapes.

Punched cards were a great improvement over tape, although the chad wasn't nearly as much fun with which to play pranks...

MikeS
September 10th, 2009, 06:37 PM
Most computer-oriented paper tapes of the 60's and later were 8 channel. The 8th channel was normally used for parity, unless binary was being punched.

However, paper tape was used on a lot of gear, from early CNC to telegrams. Tape using 5 level Baudot encoding was used for a very long time. There are also 6 and 7 level paper tapes.

Punched cards were a great improvement over tape, although the chad wasn't nearly as much fun with which to play pranks...
...And then there were edge punched cards, which were more or less the size of 80 column cards but with holes like paper tape along one edge (punched and read the same way as paper tape); unlike normal punched cards they had lots of room for printed text for human eyes, and also corresponding (or different) machine-readable data along the edge.

I'll try to find some of this stuff and post some pictures.

Chuck(G)
September 10th, 2009, 08:43 PM
I'll try to find some of this stuff and post some pictures.

While you're at it, post some photos of some aperture cards.

MikeS
September 11th, 2009, 12:06 AM
While you're at it, post some photos of some aperture cards.

Ya got me with that one, Chuck; never heard of 'em till now. Neat idea though; are they still used today?

Here's a pic, shamelessly stolen from the wiki:

http://www.vintage-computer.com/vcforum/attachment.php?attachmentid=1999&d=1252656309

Chuck(G)
September 11th, 2009, 07:16 AM
I have no doubt that there are still many drawers full of them out there. Since most of these things are part of archive collections and have a very long life, there's no particular rush (or probably funding) in getting them all converted to more modern (and perhaps less permanent) media.

MikeS
September 11th, 2009, 09:42 AM
I have no doubt that there are still many drawers full of them out there. Since most of these things are part of archive collections and have a very long life, there's no particular rush (or probably funding) in getting them all converted to more modern (and perhaps less permanent) media.
That's what I was thinking; as long as there's still equipment around to read 'em, they look a lot more permanent than most modern alternatives (well, of course there's microfiche but I assume the advantage of these was that the index info was machine-readable).

I'm always impressed by the number of different and often ingenious ideas that have come and gone in the last 50 years or so...

tingo
September 12th, 2009, 02:19 PM
But I was just teasing you with my "smart ass" comment and hope you didn't take it seriously (or, if you did, that you don't now);
No, I didn't take it seriously, but the oppurtunity was to good to let go of the chance to tease back. ;^)

I have heard that due to the cold climate Norwegians have even less of a sense of humour than Canadians, but that's not true is it?
I haven't met many Canadians, but I shouldn't think it is true. Most Norwegians have a great sense of humour, but we are a bit reserved, and it can take a while before we "warm up" to new people.


The reason I asked was in case you were primarily concerned with reading the tapes (instead of building a camera-based reader) then there are folks around who could do that for you, especially if they were of general interest (outside of Norway that is ;-) )
I have only three tapes; and they contains some of my old school projects and such, so I hardly think that others have an interest.

I tried to find a paper tape reader at a reasonable price, or one that I could build with components that are available at a reasonable price. When that failed, it sparked an interest in finding a general way to read paper tapes today.

Ole Juul
September 12th, 2009, 02:36 PM
tingo: I tried to find a paper tape reader at a reasonable price, or one that I could build with components that are available at a reasonable price. When that failed, it sparked an interest in finding a general way to read paper tapes today.
It's always fun to come up with ideas and play with stuff too. :)


tingo: I have only three tapes; and they contains some of my old school projects and such, so I hardly think that others have an interest.
In this case perhaps you could just mail them to somebody with a reader who could then put the info in an easily transferable file. That wouldn't be as much fun but it sounds like it would meet your primary need.

tingo
September 28th, 2009, 09:24 AM
Has anyone here got experience with those small business card scanners? Or some other usb scanner that automatically feeds the paper through.
Does it feed the paper straight all the time?
It seems that such a scanner wold be good for reading paper tapes, if one could coax it into working without the specialized software.

nathan
October 1st, 2009, 08:40 AM
Here's a silly idea...

How about using an array of 9 LEDs, mounted quite close to the tape so that they each only shine through one hole...

Then put one photodiode on the bottom, and use a multiplexing scheme to cycle through the LEDs rapidly.

Sounds like a job for a PIC or Arduino :P