My PiDP-1 Build

The kit consists of a number of PCB panels. Oscar and team came up with the clever idea of contructing the case from PCBs rather than messing around with costly injection molds like the cases for the PiDP-11/70 and the PiDP-10. This allowed them to keep the cost of the PiDP-1 kit to a reasonable $225 + shipping.

Detailed build instructions and photographs are here, so I won't bother trying to duplicate all those. There is also a great time lapse video of an entire build here.

The panels for the case are assembled by soldering tabs together on the inside of the case along the interior edges. This is done by creating small solder bridges at regular intervals. Once this is done the case is extremely rigid and solid, so this is a pretty brilliant solution. Since the case is somewhat hidden by the uniquely shaped front panel (unlike the other kits) the case appearance is not so important and is mainly structural.

Here is an example of how the solder tabs are bridged together with solder to form a rigid structure. Note the solk screening that is on the interior of the panels so you know which oneis which and the correct orientation.

It is only necessary to solder only some of the tabs - every 4th or 5th tab is fine.

I believe the CEDS team now tests all LEDs before shipping kits, but I wanted to check them anyway, as I did for the PiDP-10 kit. There are 119 LEDs, and while the chances of a bad one are small, replacing it would be a major pain once the front panel is assembled. This is a simple matter of plugging them into a breadboard in series-connected gangs and applying a power supply through current limiting resistors. Tedious, but satisfying.

Initial stage of loading the main PCB. Diodes and resistors have been installed.

LEDs (all 119) soldered in and switches loosely installed. The front panel will drop over the switches to align them prior to soldering.

IMG_3007.mov

Here is the partially completed panel in test mode. The Raspberry Pi 5 has been installed on the back of the panel and booted up with the PiDP-1 software installed on SD card.

The test script cycles all the LEDs and lets you test the switches. It turns out I had one flakey switch due to a missed solder joint. It was a quick fix.

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Here is a short video of the completed PiDP-1 running a blinkin lights demo program, loaded via the paper tape simulator in the Pi's gui.

IMG_3009.mov

Here is a demo program running that shows the type 30 display simulation - this one is called snowflake.

The Software

While the team behind the creation of the PiDP-1 had a bundle of software and demos ready to go when the kit was released, one enthusiast (a retired software engineer and fellow New Hampshirite) - Bill E - has taken on the task of rewriting virtually all the software, even creating a new assembler. He diverged from the original repository because there were so many changes and optimizations and his work is ongoing. His GitHub repo is here. He has utilized some AI tools, namely Claude, to assist with his rewrites and new implementations.

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