Not all photoresistors are as sensitive to the same light wavelengths, so for the maximum range you’d want to pick a particular photoresistor. The circuit works, but we couldn’t help but notice a few items. A resistor forms a voltage divider with the photoresistor and an external A/D reads the resulting voltage. The circuit uses a common LASER module and an ordinary photoresistor that varies in resistance based on light.

If you don’t find Morse code fancy enough, you could always refer to it as OOK (on/off keying). There are lots of options, but used a LASER and a photoresistor, along with Morse code. wanted to make two Raspberry Pi’s communicate wirelessly. He’s currently working on a replica of the king of PDPs, the PDP-11/70.Ĭontinue reading “Turning A Pi Into A PDP” → Posted in classic hacks Tagged pdp, pdp-11, PDP-11/40, raspberry pi, Raspi, SIMH The most recent was at the Hackaday SuperConferece where he gave a talk. We ran into, the creator of the PiDP-8, a few times this year. The PiDP-8/I was an entry in this year’s Hackaday Prize and ended up being one of the top projects in the Best Product category. If this project looks familiar, your memory does not deceive you.

That’s really all you can do with a bunch of toggle switches and lights, though.

The software comes with a load of compiler warnings and doesn’t run anything except for very simple machine code programs. He put those switches and LEDs on a piece of laser cut acrylic with a handsome PDP11 decal. Of course the coolest part of any blinkenlight simulator are the front panel graphics, and here didn’t skimp. built his own simulated version of the PDP-11 with a lot of LEDs, a ton of switches, and a few 16-bit serial to parallel ICs. It’s a shame these machines are locked up in museums and the garages of very cool people, but you can build your own PDP-11 with a Raspberry Pi and just a few extra components. Therefore, the best way to learn programming is with a PDP-11. There’s no better way to learn how to program a computer than assembly, and there’s no better way to do assembly than with a bunch of blinkenlights and switches.

Mac os7 emulator raspberry pi