Working Lego Punch Card Reader

[evank]

I built a working punch card reader from Lego, with an Apple //e and Lego Interface A as the middleware. https://youtu.be/Z6RxhnPO7SQ

This was much fun to build :) so I hope you all enjoy it!

[Paul B Technic]

That is very cool, great video.

[dr_spock]

Cool.   Punch tape next? 

[evank]

Nope. Too hard to make tape from Lego :) and the machine could never be precise enough to read real ones.

[markaus]

the direction you went with this is a little confusing. you take it to conventions to show kids how programs were coded onto punch cards but your implementation is so far removed from real punch cards for no real reason. Why split the "paper" into strips and feed through seperately instead of stacking the blocks together and passing them through vertically? modify the slices a little with a notch to allow the touch sensors to know where a new slice is and done, far less mechanically complex and resembles an actualy punch card whilst still using 80s only lego. if 80s only isnt your limit then the large conveyor pieces allow for limitless rolls of instructions.

[evank]

@markaus, thanks for your feedback. I'm not sure I understand what you are saying.

It's true that I slowed the machine to a crawl: that was an intention decision, so that kids can understand what is happening. Of course in a real machine, it would read hundreds of cards per minute.

[evank]

Update, 3.5 months later -- here is the fifth and final version of my punch card reader. I've been receiving excellent feedback from people who trained on real IBM equipment in the 1960s and 1970s.

This version is less realistic than the original, in that it uses a hook to grab each card rather than rotating gears/rollers, but it was much easier to build this version and make it reliable. Also kids and most other show-goers only care about the lesson of holes = data, they're not concerned with the nuances of how cards are moved.

I made this video for my Facebook groups ("Interface A" and "Square Pistons") so it refers to prior videos of interim machines. Ignore those parts. 

https://drive.google.com/file/d/1xNRnVUQ5EgyjFzcky_PxFhXiUuodDzqL/view?usp=sharing

Edited March 21 by evank