Individuals previous ample to have encountered punch playing cards in their life span are almost certainly happy to be rid of their incredibly lower knowledge density and the propensity of tall stacks to suggestion over. But out of date as they might be, they are a good device to display the basics of binary data storage: the bits are conveniently visible and can even be manipulated with very simple instruments. As an experiment to re-produce those people capabilities in a much more modern day method, [Michael Kohn] manufactured a punch card-like procedure centered on LEGO bricks that retailers device code instructions for a 65C816 CPU, the 16-bit successor to the venerable 6502.
Bits are stored on a white 8×20 stud board, onto which compact black items are positioned. A white history stud encodes a logic “zero”, although a black stud encodes a logic “one”. The bits are examine out by an array of reflectance sensors, which conveniently has the exact 8 mm pitch as typical LEGO studs. A huge wheel pushed by a stepper motor slides the data card below the readout circuit together a shorter extend of LEGO prepare tracks.
The optical sensors are read out by an MSP430 sequence microcontroller, which also drives the motor by way of a stepper motor driver. Once the facts is read through out, the bytes are transferred into a WDC W65C265SXB board, which executes them as equipment code guidelines on its 65C816 CPU. In the online video underneath, you can see a application getting loaded that blinks an LED.
We’ve showcased educational punch-card programs right before, like this Raspberry Pi-centered model. If you have got a bunch of genuine punch cards that have to have studying out, examine out this Arduino-powered readout process.