PiDP-8/I replica with Raspberry Pi

• Tweet
• Pin It

Remaking the PDP-8/I using the Pi, simh & a replica front panel: a true catching project!

Goal: a (very) low cost full replica of the PDP-8/I.

Design: use the $20 Raspberry PI Model A+, a custom front panel PCB to mount it behind, and 26 nice-to-use toggle switches. Extend the simh emulator to drive the front panel.

Reason: PDP-8 replicas can get very expensive very quickly. The idea was to do the exact opposite: design a faithful replica using minimum parts. Made possible by the fact that the computing engine is available for $20 (Pi model A+) and in software, there’s no better replica of PDP-8 functionality than the simh emulator.

Result: Pi drives the 92 leds and 26 switches using a multiplexing process running in parallel to the simh emulator. Only a few ARM instructions are necessary to update the front panel during a PDP instruction cycle. An acrylic front panel faithfully reproduces that of the original.

Components

• 1 × Raspberry Pi (Plus or 2) needs 40 pin GPIO connector
• 26 × Toggle switches
• 12 × 390 Ohm resistors
• 26 × 4148 Diodes
• 1 × UDN2981A (optional) Interface and IO ICs / Peripheral Drivers and Actuators
• 1 × PCB Designed in Kicad/Open source hardware design
• 89 × LEDs (5mm, High Brightness) Electronic Components / Misc. Electronic Components
• 3 × 1K Ohm Resistors
• 1 × 2*20 pin header for mounting the Raspberyr Pi 

 

Here is the full detailed guide to make it!

Related Posts

• 

  How to Control NeoPixel Installations via Wi-Fi Using Fishino and NodeMCU with Python
  How to Control NeoPixel Installations via Wi-Fi Using Fishino and NodeMCU with Python
• 

  Google Assistant Voice Controlled Switch – NodeMCU IOT Proje
  Google Assistant Voice Controlled Switch – NodeMCU IOT Proje
• 

  Water Softener Salt Level Monitor
  Water Softener Salt Level Monitor
• 

  Sparkly Air Sensor
  Sparkly Air Sensor