Obsolescence Guaranteed

The pidp1 software runs fine on a 'naked' Raspberry Pi, without the PiDP-1 board. Set up your Pi before you start soldering.

Any Pi from the Pi Zero 2 on up can be used. A Pi 4 is the minimum when you want to view the Type30 display on the Pi itself, and not through the Web interface. A Pi 5 is recommended if you also want to use the Pi as a normal Pi concurrently with the PDP-1.

The following is just FYI: you can get a terminal attached to the PiDP-1 in different ways. For now, testing using option 1 is good enough:

1. 1. Use a HDMI monitor and a USB keyboard, and run everything on the Pi;
2. 2. You can also use your laptop to access the PiDP-1 over wifi, using its built-in web server: this lets you run the PiDP-1 headless.
   Just place it on a bookshelf or hang it on a wall.
3. 3. The PiDP also has a serial port, to connect real serial terminals, or Teletypes.

It is mentioned further down in the building instructions, but for people who buy the PiDP-1 as assembled & tested: the Pi sits close to the PiDP-1 circuit board. Avoid any risk of short circuits: protect the metal USB connectors on the Pi with a strip cut from plastic or thin cardboard.

The PiDP-1 requires the 64-bit version of the Raspberry Pi OS. First, set up your Pi like any normal Pi: create a SD card, boot the Pi with it, set up your internet connection. Then install the pidp1 software:

Answer 'y' to all questions of the install script. You can rerun the install script later to change the setup.

Make sure that you have all the previous parts on the board before proceeding. Because if you have to redo any of the steps above, the next step of removing and fitting the Ottopanel again is a bit fidgety (though not a problem really). All the parts are on? All their pins are soldered? Check.

Soldering the LEDs:

There are 118 LEDs but actually, soldering them in goes rather quickly, thanks to the Ottopanel (Ref.#8). Alas, it does start with a little chore: put a LED spacer on each LED.

LED spacers are actually a great help when putting in LEDs. When you know how to use them; see the pictures below. The solid end of the spacer goes onto the PCB, the hollow end faces the LED. Put the LED into the spacer, with its pins only protruding a bit. Now mount the LED+spacer onto the PCB. Once the LED is in, press it in all the way. A faint click, and the LED is solidly in the right place. But best press the LED in with two fingers, not one.

Fit LED spacers to all LEDs

Polarity matters!
See the little marker on the PCB's top left, it shows they should be put in. Long pin to the right (seen from the front of the PCB).

Pushing in the LEDs. Make sure not to bend their legs put them in. They should sit up neat and straight.
Mind, LEDs have a long + pin and a shorter – pin.

Check from the side if all LEDs are fully pressed in. Also, check that all LEDs have their long pin on the correct side. Which is the right side seen from the front of the PCB, but on the left side because you’ll be looking from the back of the board!

Now, put on the Ottopanel, board Ref.#8. Its purpose is to hold the LEDs in precisely the right spot. It will become a part of the case in a next step. Some of the LEDs will not voluntarily find their way into the mount holes of the Ottopanel, preventing it from clicking into place. Shift and wobble the Ottopanel to force the LEDs into compliance, but not with too much force. You might bend some LEDs, making it more difficult.

The Ottopanel is loosely fitted here, to begin. Not all LEDs are yet fully seated in the panel (the fidgety part)
Ignore the switches visible in the photo. They should not be there yet.

The Ottopanel is fitted, all LEDs neatly peeking through the holes in the Ottopanel (the fidgety part is over)
Ignore the switches visible in the photo. They should not be there yet.

Once the Ottopanel is fitted, flip around the board set, and press it down (best: on a tablecloth) to keep all the LEDs pressed in evenly.
Solder ONE pin of each LED. Flip the board, check the LEDs are indeed neatly aligned. If one that does not, reheat & reseat it. Then solder the second pins.

Soldering the switches

Next step: place the 44 small switches onto the PCB. The Ottopanel helped to speed up the soldering of the LEDs, you'll now fit the actual front panel on top of the Ottopanel to speed up the soldering of the switches. And the other benefit of this two-step approach is that it makes the actual front panel exchangeable. You have a white and a blue one, your preference may change over time :-)

Switches have no polarity, putting them in upside-down is not a problem. But note the little groove in their screw threads? For cosmetic reasons, put them all in with the grooves facing down.

The switches have been pushed, through the Ottopanel, into the PCB. They will sit there all wobbly for the moment, because the Ottopanel leaves them too much space. That is the point, though --

Now fit the actual front panel (Ref.#10 is blue, or Ref.#12 is white) onto the Ottopanel. Make sure the switches find their way through their front panel holes. You might also need to fidget a little to get the LEDs into their new holes. But not much.

1. Hold the PCB set, pressing a finger against a switch whilst soldering its middle pin only.
2. Or, place a flat bit of cardboard (better, a wood cutting board from the kitchen) on the top of the switch handles, so they’re all pressed into place.
   Flip over on the table and solder them all – just their middle pins.

In the photo, we placed three nuts next to the switches onto which you have to screw them. That will attach the PCB to the Ottopanel and to the front panel. You can put nuts on more switches if you like, but these three are the minimum.

Close-up of the nuts on the switches
with the nuts put on them

But one last picture of what you have constructed. We call this the Sandwich, a combination of PCB + top Ottopanel + top frontpanel. It's ready to be mounted in the case.
Note: your photographer forgot to put the solder tabs on. Don't make that mistake!

Finish the electronics

• Insert the 3 ICs into their chip sockets on the main board.
  
  From top to bottom, the ICs are UDN2981/TD62783AP (P1), 74HC238 (U1) and 74HC138 (U2)
  ...and because it happens, if you swap the 138 and 238 around by mistake all the front panel lamps will always be lit up.
  ...another common mistake: putting the ICs in the other way around. Mind the notch, match with the footprint.
• Plug the 11-pin ribbon cable into the switch PCB and on the other end, into the pin header on the PiDP-1 main board.
• Insert the prepared Raspberry Pi.

Power up the Pi after you've connected the HDMI and keyboard cables.
Open up a terminal and type:

pdp1control stop
/opt/pidp1/test.sh

See if all the LEDs work. Note the ones that do not, and check their soldering.
If that does not solve the problem, see the page Debugging the PiDP-1

See if all the switches work. Note the ones that do not, and check their soldering.
If that does not solve the problem, see the page Debugging the PiDP-1

Before you think that the DEP switch does not work: the DEP switch works the other way around - you have to push it UP, not down to get a signal!

The Rack version, of course, comes with both the Console and the Rack case. You should mount the PCB set into the Rack case first. That means that you will solder the Ottopanel, which is now part of the PCB set, onto the Rack case.
Once that is done, you should consider the white front panel as a spare Ottopanel, and solder that onto the Console case. Then, you can transplant the PiDP-1 circuit boards between the Rack and the Console case at any time.

But first, follow the instructions to mount the PCB set into the Rack case. The console case is for later.

This works the same for the Console and the Rack cases:
take the sandwich of PCB+top Ottopanel+front panel, and slide into the front of case. Position it so that it sits tightly against the switch panel (the #9 that is already part of the PiDP-1 case). You might need to bend the three little solder tabs in a bit so they stay clear of the bottom Ottopanel.

Place 'the sandwich' (of PCB+top Ottopanel+front panel) on the bottom Ottopanel (which already part of the case) and push it into the case.

Close it up...

...Close it up further...

Use a bit of tape once you're happy with the horizontal positioning (lower corners of top Ottopanel lines up perfectly with the corners of the bottom Ottopanel). The switch PCB, Ref.#15

Tape it up...

Looks good. But will look better once the back panels are clipped in, later on!

To be precise: after you've lined up the top Ottopanel so it precisely fits with the bottom Ottopanel, as per the section above, you can now solder the sides and top edge of the Ottopanel to the PiDP-1 case. Do one solder point per side first, and check if indeed the two halves of the front panel are still neatly aligned. If not: reheat & reseat. If the alignment looks good, solder up all the other solder points as you did when you constructed the case: solder one in five solder tabs together, that is more than strong enough.

Soldering the Ottopanel to the case. Remember: Only do one solder spot per side (left, top, right), then check for alignment of top and bottom panels again! If not perfect: reheat & reseat. If perfect: zip up the sides with more solder spots. If you do one out of every five solder pads, the case will be indestructible, that's enough.

Bend the little solder tabs at the bottom of the top Ottopanel so they sit against the matching solder tabs of the bottom Ottopanel. Solder them up whilst pressing top and bottom Ottopanel together, so there's no air gap between the two halves of the front panel. Instead of pressing, you can also use tape to fix the two parts tightly together before soldering.

A fix that some builders may need

A quality hack for a design imperfection, we like to think!
Some builders noted that the panel lamps on the top left are not fully pushed through the front panel. It depends on the tension between the Ottopanel and the PCB. But for some, if they push on the PCB behind it, the LEDs come out more on the top left. Once you see it, you can't unsee it! Annoying.

Here is the solution.
Solder a wire or spare resistor/diode across this corner of the main PCB. Because there's no switch on this part of the panel, there's no nut on a switch to fix it tightly. It looks like a hack, it smells like a hack, but it is a perfect hack. We preferred it over adding a tricky-to-align solderable bolt nut.

The 'spacewar' game controllers are simple to build. This will be the end result:

The assembled spacewar game controllers

Front side

Back side

• Cut off about 2cm of the cable's mantle (the outer plastic) to reveal the 5 wires inside.
  Tip: keep the cable in a sharp bend while you cut the mantle. Only a few shallow cuts will suffice to let the mantle tear itself open.
• For each of the 5 wires inside, remove about 3mm of the insulation. A sharp knife will do the job.
• On each wire, turn the copper strands a few times to make them stick together, then tin the ends with a bit of solder.

• solder on the 5 tact switches
• solder the 6 diodes
• mount the 5 wires from the cable
• use 2 tie wraps to tightly hold the cable in its place at the bottom of the PCB

The game controllers are kept very simple for a reason.
They have a second purpose: they can also serve as the PCBs inside homebrew controller boxes. If you google around on 'PDP-1 spacewar controllers' you will see that it is a good tradition to make spacewar controllers from a clunky wooden box and some old retro switches. Even in the 1960s, there were many variants using all sorts of switches, levers, buttons. Below is some inspiration, if you are tempted:

So if you want to keep that tradition: find yourself two wooden boxes and some old switches (especially the lever types are hard to get, hunting for them is a in fact hobby for some spacewar fans). Below each of the tact switches on the controller PCB you will find a footprint to solder wires to whatever switch you like. And then, the controller boards can serve as the PCB inside a proper homebrew spacewar box. That is why the controllers come with mount holes, to fit them into some box!

Again, note the colour of each wire, and the order into which they are soldered on the game controllers. Then, solder the coloured wires to the connector in the pin order as shown in the pictures below. As always on this page, click to zoom the images.

Use some sort of a clip or clamp to hold the connector. It makes the soldering much easier.

Start soldering the wires from a controller, like so, on the bottom row of the connector - the row with 5 pins.

Adding the wires from the other controller - note that its brown wire shares the same pin as the brown wire of the first controller!

The other wires of the second controller go on the top row of pins. Note that I turned the connector upside down for this shot.

The connector case has plastic blocks that surround the cables

Put them around the cables, then put the clamped-together blocks in the connector case

The other wires of the second controller go on the top row of pins. Note that I turned the connector upside down for this shot.

Wiring diagram, in case of doubt and confusion.

The Raspberry Pi 5 has a tiny push button on its side, to power it on and off. Because this will be hard to reach when the Pi is mounted in the case, we added an external tact switch to fulfill its task. That tact switch can be mounted on the lower back panel (Console version) or on the left of the bottom rack panel (Rack version)

Building steps:

Solder a 2-pin header on the raspberry Pi itself

Console version:
Solder the tact switch on the front, and a 2-pin header on back of the PiDP-1 Console back panel.

Connect the cable between Pi and PiDP-1 back panel.

Rack version:
Solder the tact switch on the front of PiDP-1 Rack bottom panel.

Cut off one of the connectors from the 30cm F/Frainbow ribbon cable, and solder the wires (SMD style) straight on the back of the PiDP-1 panel. Connect the Pi with the other end of the cable.