My pidp1 hardware hack

[Bill E]

In the tradition of PDP-1's being hardware hacked frequently, here's my contribution.

No, not a single PDP-1 ever had a display instead of a tape reader on the reader/punch panel. Of course, not a single PDP-1 ever had a tiny display in a speaker hole, either. :)

That big blank space was begging for something. The screen is also a touch panel, I can completely manage the rpi also, no external connections needed.

Bill

[R Clark]

That is really neat!  You took it to another level for 2025 :) .

[Charles Ess]

That's really gorgeous - congratulations!

Quick question: are the details of using the display as a touch screen to manage to rpi obvious once I get that far (I'm still on the waiting list for the kit, so I've not delved into the building instructions very closely, so please feel free to tell me to RTFD) and/or do you have some tips and suggestions based on your experience of doing so that you can pass along?

[Bill E]

At least for the display I got, it was just plug it in, touchscreen worked. Apparently the rpi supports touchscreens out of the box. It even pops up a touch kbd when it detects text input needed. One thing I had to do was to remove the terribly annoying orca pkg, it speaks everything you do on the screen, apparently automatically enabled. Lots of stuff on the web about it. You can also toggle the use of the touchscreen popup kbd on and off via the desktop Preferences/Raspberry Pi Configuration utility.

The display I ended up using was a  waveshare 7inch HDMI LCD IPS Capacitive Touch Screen 1024×600 Display Monitor, $47 on Amazon.

You do have to edit /boot/firmware/config.txt to tell the rpi the characteristics of the display, but there are clear directions provided.

Bill

[sunnyboy010101]

Bill,

Could you post a larger photo of the frame, and provide more details of how you attached everything to the panel? Did you just drill a small hole for the wires, or cut a larger hole (etc)? I love what you did and want to do something similar, hence the questions.

Also, is the frame a 3d print? Do you happen to have the files for it?

Thanks,

-Richard

[Bill E]

I'll take some better pics. Yes, I 3D printed the bits, I'll post the files as step files, or Bambu 3mf files if people want. They would probably need tweaking for a different display.

Otherwise, pretty straighforward. Carve a hole in the tape panel to fit the printed bezel, screw the backplate on the other side. One added benefit is that the black back frame overlaps the metal separator strips which really stiffens up the panel, good for plugging into the USB slots.

Bill

[Curtis Smith (史國興)]

I have tried to use a small touch screen on my PiDP-10 but ran into some problems with the pop-up on-screen keyboard as I could not find how to bring up the ctrl, alt, & esc keys, so it was not very useful in bringing up ITS, for example.  DId you encounter similar problems with the PiPD-1, or does it not need these keys? 

[Oscar Vermeulen]

For the 7" display behind the middle two speakers:

Just drop the display in the slot, prop up its back to it is pressed to the speaker panel on the front. If your display is one of those with little mount tabs, there's slots in the rack that will fit them. But it's not necessary.

Then, fiddle with the F2 mode of the GUI to position and size the elements (Type 30, paper tape reader/punch, typewriter) so that they neatly fit behind the round speaker slots.

Check the manual, the GUI program can have multiple settings. So you can have the Typewriter behind the left speaker, the Type 30 behind to other. Then hit a function key to roll to another layout that you set up, with perhaps the paper tape reader/punch and the Type 30. There just was a little update on the function keys, see https://obsolescence.dev/pdp1-manual.html#GUIkeys

We still have to add a mode where you can have BOTH Type 30s shown at the same time. That was not an official PDP-1 feature, but Norbert's discovery of the dual-display spacewar creates an urgent need for such a setup. Fun to read about too:

https://www.masswerk.at/spacewar/4.4/, scroll down for the history of this Hack.

Actually, programming for the dual-screen PDP-1 is not hard at all. It works on the PiDP-1, but you have to use pdp1 type30b to get the second display. And before I post this, I had better checked if that is in already. If not, them tomorrow it is.

But the proper fix will be when Angelo adds the second Type 30 as an element in the GUI interface by default.

Kind regards,

Oscar.

[Oscar Vermeulen]

I never used a touch screen, actually. But I did read that the new Pi OS has a much improved on-screen touch keyboard now.

[Bill E]

It does seem to work well, but I doubt I'll use the kbd much. The main use is to drag the peripheral display to the side so I can load/punch a tape, start/stop the emulator, then drag it back.

Bill

[Oscar Vermeulen]

Bill,

On Tuesday, October 7, 2025 at 2:11:00 AM UTC+2 wjegr...@gmail.com wrote:

It does seem to work well, but I doubt I'll use the kbd much. The main use is to drag the peripheral display to the side so I can load/punch a tape, start/stop the emulator, then drag it back.

Oh I see! You are using the virtual panel, not the PiDP-1 hardware still! Did you get an email from Jose, and is the PiDP-1 on its way? We need to get you one :-)

Shipments of PiDP-1s have been delayed for a week, because we had feedback of Bad Leds. So now we're checking all the LEDs for every kit. What joy that is...

I had never thought of using the touch-onscreen keyboard widget, I expected either a Bluetooth keyboard or a regular one (but that means a wire to the Rack, indeed).

Kind regards,

Oscar.

[Bill E]

Here are the stl files for the front and back LCD mount. The holes in the front are 3.3mm to be self-tapping for M4x12mm screws.

You need a cutout that will fit the extrusion on the front panel, then drill some oversize holes as indicated by the back panel. Oversized so you can wiggle it around a bit to line things up.

Be sure to align the back and front, one side is slightly narrower than the other.

Bill