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Punched Cards Rebirth project help? Answered

I'm kinda relying on instructables lately, hmm...

We have this project with my friend (not just in 'ibles), nutsandbolts_64 and we are trying to relive the past and do some stuff from the "mechanical computer" era. He did aperture cards as he wanted some form to store blueprints and stuff, i'm doing paper punched tapes. I decided to use the 2 hole tapes, the one using the international morse code system. As with many projects, i have a few problems that you may help me with:

Is 10mm(w)x1000mm(L) made out of cut and spliced A4 paper good enough for that purpose?

Do i still need to punch the holes in the center? (the guide holes thingy)

Will a regular needle be thick enough or do i need to get something thicker? (I'm gonna punch it manually, so a needle would be easy to handle)

What kind of switch can i use to "read" the data electronically? (I'll pull it manually, no need for a motor)

Just in case someone has done his, can you please share your photos?
Best answer will get a patch!!!!!!!!!!1!!!!1!!!1!!11!! joke, I'm not a pro member XD
Thanks in advance

7 Replies

beehard44 (author)2010-10-30

i was thinking of using LDRs and transistors to detect light from the holes and feeding them into the computer via the audio or serial port...
wait, i remember a program from scitoys...

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Unfortunately, the reader there isn't intended for morse code on the tape. It uses holes to signify 0's and 1's. It is interesting though.

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beehard44 (author)2010-10-27

i was thinking if i can make a program that reads it through the serial port, but what pins can i use for the dits and the dahs?

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lemonie (author)2010-10-27

I have an 8-bit reader half-built, but the read-heads are a bit of a sod at the moment. That's Lego (mostly).


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orksecurity (author)2010-10-27

I've never seen morse used for this purpose. And I wouldn't recommend it; morse is timing-sensitive, and compensating for tape-speed irregularities is going to be a pain in the neck.

The holes in the center of punchtape were for the drive sprocket. If you're driving the tape by friction, or pulling it by hand, you don't need them for that. You may need them in order to sense tape speed; see previous item.

Whether any given size/shape/length of paper is sufficient depends on how much data you want to record, how densely you record it, and how you're reading it.

Whether a needle will work depends on how you're going to read it. I'd think holes punched with a needle would be somewhat error-prone, since paper pushed out of the way may be squashed back in and fill the hole again. The old equipment used punches (flat-ended wires driven through openings so they would neatly cut out circles of paper).

Reading the data: Simplest would probably be optical.

Have fun...

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