This program makes flashing light patterns on Oscar Vermeulen's PiDP-8, a simulated PDP-8 console panel driven by a Raspberry PI.
The goal of this script is to interface to the PiDP-8 in Python, to make it simple to experiment with different light patterns.
There are other tools for this, including
- Deep Thought This is actually implemented in PDP-8 assembly, using the PDP-8 Simulator for the PiDP-8
- Deeper Thought 2, implmented in C
Writing this in Python should make it easier to experiment with creating interesting patterns.
The package is written in Python 3 (Python 2 becomes obsolete soon). You'll need the Python 3 version of the RPi.GPIO library installed:
sudo apt-get install python3-dev
For some reason, the script leaks resouces and starts slowing down after running for several hours. This gets to the point where the display starts to noticeably flicker. In order avoid this, it exits after about half an hour. Another script, RunLights.py restarts PDP8Lights.py it with a new heap to avoid the slowdown.
Since the GPIO library accesses privledged system resources, you'll need to run the script as root:
sudo python3 RunLights.py
Holding down the Stop switch (third from the right) for a few seconds cleanly exits the script.
This was tested with a Raspberry Pi 3 installed in the original 2015 version of the PiDP-8. The schematic I have from that era lists GPIO pins 3 and 5 for col 1 and col 2, however these are actually connected on pins 8 and 10 on my PiDP-8. Check this if a couple of lights on each row aren't coming on. You may need to adjust the timing variables for other Raspberry Pi models.
I doubt Python is fast enough to do PWM (Pulse-width modulation). If you want variable brightness, you'll probably need to code this in C.