Reading Paper Tapes From Scratch!

Home made tape reader

Feeling a little nostalgic? Dying to read some paper ticker tapes? You can do it manually, but that’d take forever! [NeXT] decided to make a little PCB to help him out.

Having searched for paper tape readers for years, and even getting halfway through building the mechanical portion of it in his high-school tech class, [NeXT] decided to take a serious stab at it — and by golly, it works!

The reason he finally decided to go down this route is because you just can’t buy them (well, for cheap), and even the DIY or hobby ones out there are notoriously slow — what better reason to design it from scratch?

What we love about this hack is its clever reuse of perfboard — it just so happens that the spacing of his paper tape holes line up perfectly with the holes in the perfboard! Don’t you love it when engineers work together with nice, even, standard units? After discovering this it was just a matter of adding some photo-transistors on one side of the perfboard sandwich, and LEDs on the other side.  A bit of soldering, some Schmitt triggers, and an Arduino Pro Mini later… and bam you have a serial output of data!

The funny thing is — he does actually have a working ASR33 Teletype reader — but it’s too slow. Maybe we should mail him the secret message Hack42 gave us on paper tape when we visited them in the Netherlands!

[Thanks John!]

36 thoughts on “Reading Paper Tapes From Scratch!

  1. By “nice, even, standard units” are you referring to 2.54mm?

    Jes’ yanking the chain, awesome hack! I sharpened my computing teeth on ASR33 tapes and 20ma current loop acoustic couplers. Ah, the good times in HS computer programming (DEC PDP8/e at the other end of the phones, running Edusystem-25 Basic).

    1. The PDP8/e…I remember it well. The best thing that every happened, was when it broke. I learned so much about computers by studying the schematics in the process of fixing it. Who needed hex, when octal was available?

  2. I remember reading PDP boot tapes on an optical reader. These were mylar tapes designed to last “forever”. We would pull them as fast as we could to see how quick the memory was. I don’t remember getting too many boot failures, until the “forever” tapes broke.

  3. I have a kit version of this from the CP/M days. It can read paper tapes as fast as you can pull them through. I still have the “nekkid chick” pin-up calendars on paper tapes from back in the late 60’s. I wonder how brittle they might be by now…

    1. I still have an ASR-33 with tape reader and punch, but after a decade stored out in a shed, it will probably need a serious overhaul before it will ever work again. Ahh, the good old days of 10 bytes-per-second online access.

        1. yes it will. grease and oil wil harden and turning it on without a manual check can break parts. trust me, i’ve had to fix a couple of mechanical wonders like the asr33, flexowriter, telexes and mechanical cash registers

  4. I used a paper tape reader to program a Motorola MEK6800* in the late ’70s. I wished it had some sort of hand-cranked spool to move the tape rather than relying on pulling it by hand. That would make it easier to maintain a steady speed. Motorized would be better still. So my suggestion for an upgrade to this neat little project – tape advancing system.

    *GE 4020 cross assembler output on an ASR33 punch made life a lot easier than punching in the machine code directly in the 6800’s hex keypad.

  5. Somewhere in storage I still have an 8 channel optical tape reader. I think it read at 300 characters per second. It had a motor to pull the tape. I have a punch too, but it may only be 30 characters per inch. (This is when I first heard about “hanging chad”) I also have some old tapes I made when I connected long distance over 300 baud to the BBS at the Catholic University of Washington, DC back in the late 70’s. I wonder if they would be interesting??? Sounds like something I need to dig out again.

  6. I took out a patent in about 1968 on using 2 input nand gates and two photocells to pick up the clock track so that the reader would NEVER make a mistake. I gopt the reading speed up to 10000 CPS after that THE paper would rung out in seconds.

  7. I have some old 7-track paper tapes from my high-school days (circa 1975). If someone has a reader I would love to get them transcribed. Will happily send you some board/dice/card games I have published over the years as a thank-you.

  8. I have just finished interfacing a Heathkit H10 paper tape punch/reader to a PC EPP printer port. It works nicely however If you don’t know what is on the tape then there are problems as a nul (no holes) or an FF (all holes or end of tape) are valid binary data so reading a raw binary tape is problematic unless there are headers. I am about to do some recovery of a lot of old tapes that are not labelled so I am thinking that there is going to be some manual work with hex editor or such like. I guess that’s why DEC had Absolute loaders and “Read In Mode” loaders to manage binary paper tapes.

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