Ever want to go back to the “good old” days of computing, when all coding was done on punch-cards? OK, maybe you don’t, but it’s always fun to combine old technology with new concepts, like this interface that let’s you tweet via punch cards.

The first step in making this clever retro-computing experiment was how to actually read the cards and transmit this information into a modern computer. The reader was made, after a brief attempt using mechanical contacts, with a series of infrared LEDs and photo-transistors salvaged from an HP print station. These LED/transistor pairs were attached to two plastic cards so that when a punch card is passed between the two, it can tell whether a hole is punched or not.

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This data is decoded by a Teensy 3.1 per IBM model 029 keypunch codes found here. This Teensy microcontroller then acts as a USB keyboard to the “mother” computer, transmitting whatever text equivalent is contained on the card. If you’d like to try this kind of experiement yourself, you can find the code on TimJay’s GitHub page, or you can just follow “it” on Twitter.

So far the reader hasn’t said much, but I’m hopeful there are some interesting quips on the horizon!