The maker in question – Nino Ivanov – calls his “mainframe” 1V0 Tz III, and it is featured on electromaker.io.
Basically, if I have understood correctly, the holes in the cards are detected by the use of LED lights on one side and photoresistors on the other, which are connected to the analogue inputs of the Arduino for processing. Your on and off are detected by the presence or absence of light. Neat.
It uses a 6-bit system, rather than 8-bit, so requires it’s own encoding system. Thus, the hardware components comprise six light emitting diodes, six photoresistors, the Arduino Uno itself and cable, some wires and some wood…
You can find his code on Github, but I guess one of the hardest parts will making a ‘chamber’ through which to pass the punchcards. The 3D-printers among you will relish the challenge, I imagine. As best as possible, each LED/photoresistors combo needs its own private space.
“The six light emitting diodes are hooked up in parallel to be lit up by the Arduino (no special control necessary, they shall just be made to emit light), and opposed each diode shall be one photoresistor. The lights shall be arranged physically in a line, and in a best practicable way shall be so isolated from each other that neighboring lights do not trigger neighboring photoresistors, but each LED only ‘its own’ photoresistor.”
“The photoresistors are to be connected to the A0-A5 analog inputs of the Arduino UNO. The whole setup shall be made so that a carton card can pass between the lights and the photoresistors, and where there are ‘punches’ on the card, the light will shine on the respective LED’s resistor – and where the carton is intact, not.”
As you can see in the video below, he demonstrates detecting commands, adding numbers and processing memory addresses…
Excellent. Read more about the project here.
By the way, if you want to read a bit more about Punch Card history – and there is a lot if, going back to 1804 and up to the Seventies – then Google Arts & Culture has a roundup.
Joseph-Marie Jacquard started it with his automated looms, and then Herman Hollerith partially mechanised data processing for what was the 1890 US census, using the punched cards to store the personal information….
“Arduino has been united with the 1950s to bring you the true power of computing.”
Nino Ivanov turned an Uno into a punch card-controlled computer that outputs results through its serial port. https://t.co/R8VO8pMHhP
— Arduino (@arduino) May 3, 2023
See also: Raspberry Pi enables Bluetooth retro payphone