These old plenty of to have encountered punch cards in their life span are in all probability glad to be rid of their particularly low facts density and the propensity of tall stacks to idea over. But out of date as they may perhaps be, they are a wonderful instrument to demonstrate the fundamental principles of binary info storage: the bits are simply noticeable and can even be manipulated with simple resources. As an experiment to re-make those people options in a more present day process, [Michael Kohn] designed a punch card-like procedure primarily based on LEGO bricks that stores machine code instructions for a 65C816 CPU, the 16-bit successor to the venerable 6502.
Bits are saved on a white 8×20 stud board, onto which modest black items are positioned. A white qualifications stud encodes a logic “zero”, when a black stud encodes a logic “one”. The bits are read through out by an array of reflectance sensors, which conveniently has the same 8 mm pitch as typical LEGO studs. A major wheel driven by a stepper motor slides the information card below the readout circuit alongside a shorter stretch of LEGO teach tracks.
The optical sensors are go through out by an MSP430 collection microcontroller, which also drives the motor by a stepper motor driver. The moment the info is examine out, the bytes are transferred into a WDC W65C265SXB board, which executes them as machine code guidelines on its 65C816 CPU. In the video under, you can see a system remaining loaded that blinks an LED.
We have highlighted educational punch-card techniques ahead of, like this Raspberry Pi-based product. If you have received a bunch of real punch cards that will need looking through out, verify out this Arduino-powered readout procedure.
