If you were one of the earliest of early adopters in the home computing revolution, you might have had to settle for paper tape mass storage. It was slow, it was bulky, but it was what you had, and that gave it a certain charm that’s hard to resist. And that charm is what [Joshua Coleman] captures with this DIY paper tape reader build.
If the overall style of this project looks familiar, it’s because it was meant to echo the design themes from [Joshua]’s Coleman Z-80 modular computer. The electronics of the reader are based on [David Hansel]’s take on a paper tape reader, which in turn was meant to complement his Altair 8080 simulator — it’s retrocomputers all the way down! [Joshua]’s build has a few bells and whistles to set it apart, though, including an adjustable read head, parametric 3D-printed reels, and a panel mounted ammeter, just because. He also set it up to be a sort of keyboard wedge thanks to an internal relay that bypasses the reader unless it’s actually playing back a tape. Playback speed is pretty fast; see the video below for details.
So far, writing the tapes is an offline process. [Joshua] uses a Python program to convert ASCII to an SVG file and uses a laser cutter to burn holes in lengths of paper, which are then connected together to form a longer tape. A logical next step might be to build a feeder that moves a paper tape across the bed of the laser cutter in sync with the conversion program, to create continuous paper tapes. Or, there’s always the old-school route of solenoid-powered punch and die. We’d be thrilled with either.
Now someone just needs to design a high speed paper tape punch so it has something to read. Laser cutting the tape is way slower than the already slow punch on a teletype.
That would be a fun project. I wonder what the best way to do that is? I’m trying to think of a mechanism that involves 3 or fewer motors excluding the spooling.
hmmm
One spring loaded hole punch “needle”(?) per possible position (for a single row?).
Motors:
1. Mask selector (circular plate with 2^n sets of holes for n possible hole positions)
2. Hole puncher. Either by “loading” all springs (pulling back) & letting them loose where only the by 1. selected go through – Or by pushing all hole punchers through the paper with the blocked ones “getting by” via some springy mechanism (cams with springs? I’m sure there’s a way)
This is probably a horrible design but if you’re constrained by the number of motors…
Getting it right might be more challenging. High speed punches are pretty clever mechanisms. You need to sync the data input to the rotation of the punch cam.
Someone’s already done most of the work (see page 6) for you:
https://www.navy-radio.com/manuals/tty/jk/592-802-100-iss3-6403.pdf
The ANSI specification for the paper tape reels recently went up on Bitsavers, for interest’s sake:
https://bitsavers.org/pdf/ansi/X3/X3.020-1967_Take-Up_Reels_for_One-Inch_Perforated_Tape_for_Information_Interchange.pdf
Glad you dig! Just a a quick correction THIS is the design whose aesthetic it’s meant to match:
https://hackaday.com/2022/12/20/the-coleman-z80-is-a-modern-take-on-a-1970s-computer/
Please tell me, that the left, static axel ist not a brass one. Because it’s so close to the main power input, that it could be the last time, when you put the reel on the Machine. Very dangerous.
im usually not a “oh noes” kind of person, but it is super close to the IEC connector heh (hopefully its wired with the colors in the right place, that would put it closest to neutral)
Worry not, the forced perspective makes it look close but it is not at all. You’re looking top-down. It has good spacing and the extending brass rod has since been shortened.
that is only from this specific perspective. the iec connector sits low on the back plate. the axle is vertically in the middle of the casing.
Is there one to punch out a tape? I could see this as a ‘paper backup’ for passwords and other sensitive data at home since few to none would have one of these contraptions to read it. Security by obsurity.
Eh, everybody has a contraption to read a paper tape: their eyes.
Just no so fast as a paper tape reader. But with a bunch of practice, I think one could learn to read a paper tape fast enough to amaze the onlookers. :P
Mark 2 standard eyeballs did a decent job reading tape headers back in the day. Fast enough so that the operator didn’t yell at you to hurry up. Like reading punch cards but easier. Memorization of the code was tough, however.
The Vintage community has many people with paper tape punches (I’m one of them) who would be happy to help.
https://forum.vcfed.org/index.php
getting the right type of paper might be a problem though. afaik it’s not made anymore. some punchers need oiled paper to not wear out the punch block too fast. i had some succes cutting a big roll of paper on a table saw, but the paper was too flimsy to be usable.
David over at Usagi Electric restored an old Facit 4070 that did just that, at speed, and with an RS-232 interface to boot.
https://www.youtube.com/watch?v=jBaMJcATHHY
Where can you buy proper paper tape?
Taping together sheets seems woefully tedious and prone to malfunction/error.
It might be possible to build a simple fixture with aluminum angle and a razor blade to split (wider) calculator tape… but that doesn’t get you index holes.
i have mused from time to time about building punched tape stuff around ribbons commonly found in fabric stores rather than standard paper tape dimensions. musing is as far as i’ve gotten, though…
Don’t know where you’d buy paper computer tape but I think paper drywall tape might not be self adhesive so it could be useable (though it does seem to be a standard 50mm wide)
I seem to remember the paper was oil impregnated to help it move through the mechanism. I think that would be the bigger challenge to recreate.
Quick search https://www.altparts.com/computer-paper-tape-a8696a.html?srsltid=AfmBOops5ezvgLEIGozPiBLAKbJYs_8Wqk-_xdFIoUP8Rj9T-MJZvStoC5Q
Guessing NOS that they have sitting around. When its gone they won’t restock.
Neat!
It would be fun I think to have a paper tape reader/writer I think. And it would not have to be ‘full scale’ and take up a lot of room. Just the idea of feeding it tape and reliably reading a program in, or writing it out would be awesome. One could also envision a smaller ‘card’ reader/puncher as well say using index cards for example or smaller yet, business card size….
Come to think of it, maybe 1/3 size to compliment the PiDP series of DEC computers :) .
How much paper tape would it take to store a feature-length movie? LOL
There are actually a few machine shops still using paper tape for CNC programs.
its 120kb/roll, so do your calculations.
My mouse pad is on a cabinet of drawers where top one is pulled out and covered under it are 32 blue plastic flip top cans for paper tape one or two may still have that tape in them the rest are sorted chips and transistors. 32 times 6 drawers each can is about 2 inches in diameter. Not much for a stick figure movie, it came from a metal shop about 30 years ago. One has a label Moog Brake part# not the synth of course.