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

[sunnyboy010101]

Bill, 

Checking on amzn.ca, the specs on the waveshare 7" HDMI (https://www.amazon.ca/Waveshare-7inch-Capacitive-Raspberry-BeagleBone/dp/B01HPV7KL8/ref=sr_1_8?crid=18AJTP8V7X931&dib=eyJ2IjoiMSJ9.okqFB6rtZdXcNEbcI9j4_FAYwr4PHCTfnFlyR2udFyswR-oxp4we-WCT4mH-suUq8vpNQmx148zkJVlFBnFGCwruwLc4Gz1lXSZyvhksMHNa3FJeC-Nkl5pY_dGAICyid9ImOKLXhGP4_O2d8UFY-rJuWfm1CHc-k4np8vYtWQPC5KqUQn-14NdT3jyzuYGTA0WyAmtx0LRh8LN1g69H0Fq01jsQ5qzfPdlyanuOHfcN2sy-5-XTT3dW6pgFn_7fIGWzy1_2S4wHeFMx_OzNXg9NCOD7EI31t_20SR5lp0k.je_bHtG1n9rqnMPn7LIewfR4cBUQBMhdiM0_ju8QW3s&dib_tag=se&keywords=Elecrow%2B7%E2%80%B3%2BHDMI%2BIPS%2Bcapacitive%2Bdisplay&qid=1768019096&sprefix=elecrow%2B7%2Bhdmi%2Bips%2Bcapacitive%2Bdisplay%2Caps%2C247&sr=8-8&th=1) 

the  measurements down the page show total length 164.9mm, and height 124.7mm. But when I measure the open space on the paper tape panel I have plenty of room for length, but the height I measure on my PiDP-1 is 120mm, or about 4mm short. This includes the mounting tabs. The measurements to center hole are 156.9mm x 114.96, which does fit.

Did you have to do any mods to the Waveshare monitor to get it to fit? 

Did you mount the monitor on the front of the paper tape panel?

Or did you cut out a square in the paper tape panel and mount the screen from the back?

I'm reluctant to buy something that won't fit 'as delivered'.

Thanks,

-R

On Monday, October 6, 2025 at 3:53:28 AM UTC-7 wjegr...@gmail.com wrote:

[Bill E]

It was fairly major surgery, I cut the entire section where the display goes out of the paper tape panel resulting in two separate panel pieces. The panel is then held in place by the front frame I printed and the back LCD mounting plate. It just fits, which is necessary since there is no tape panel behind it to hide the top and bottom. The front frame has a raised bit the thickness of the panel, so when inserted from the front, it's flush on the back. The LCD mounting panel then goes on the back. It's the same thickness as the lcd display on the lcd pcb, so the end result is the pcb of the lcd lies on top of the mounting panel and is then held in place with some screws and washers. The holes in the back mount are oversized so things can be shifted slightly to allow minor alignment corrections. The screws go thru the back mount and screw into the front frame. The result is actually much sturdier than the original panel.

Hope this is clear,

Bill

Hope this is clear.

[John Stout]

Could you post a photo? I think I can imagine what you did but it would be nice to confirm. 

It's a neat idea, and I'd like to investigate doing it on mine. I might chicken out!

John

[Bill E]

On Saturday, January 10, 2026 at 8:37:00 AM UTC-5 cuspco...@gmail.com wrote:

Could you post a photo? I think I can imagine what you did but it would be nice to confirm. 

Take a look at my first post in this thread, some pics there. The stl files are in my second post. There is a bit of a misalgnment between one of the holes in the back frame, I should fix that. I ended up just redrilling the hole.

Bill 

[sunnyboy010101]

Thanks Bill!

It sounds like your particular HDMI screen doesn't have those mounting tabs. It's the tabs that make that version "not fit" (too high) on the paper tape panel. I notice that Waveshare has several versions for sale in the same listing - some bare with tabs, some in cases without. I'll explore some more for one that fits. I want to mount my panel on the surface (on top) of the paper tape panel - perhaps even with stick-on velcro or similar and just have a small cutout for the cables through the panel.

-R

[sunnyboy010101]

Quick update. I had another look at all the available touchscreens and ended up choosing the Elecrow 7" one:

ELECROW 7 Inch Touchscreen Monitor for Raspberry Pi - 1024x600 IPS Capacitive Touch Screen HD Mini LCD Display with Stand Compatible with Raspberry Pi 5/4B/3B+/3B, BB Black, Win11/10/8/7, Driver Free"

It's sized to fit nicely (same length, but only 102mm high which fits easily), has attachment points on the back so I could drill thru the paper tape panel to attach it, has two speakers (may solve my entire Pi-5 sound problem posted on other threads), and would only need thru holes (from behind the screen) for the HDMI cable and power / touch cable). Same price as the others, and someone else already posted about using a Elecrow screen with success.

-R

[Norbert Landsteiner]

Neat!

For authenticity, this is also where the MIT-RLE machine had the commemorative plaque regarding the donation by DEC.

So it's kind of the canonical place to put any additions onto the PDP-1.

Best,

Norbert

[briandenley]

Love it.  I am sill building by I hate the idea of putting a 7 inch display behind two round holes.  Your idea is MUCH better.

Brian

[sunnyboy010101]

The Elecrow 7in HDMI touch screen arrived today. It has some stuff I really like, such as speakers (so HDMI sound is an option) as well as an audio out jack (headphones) so, could remove the audio USB dongle and plug the amplifier / speakers directly into the HDMI screen.

It has nice back mount (brass headers) so can be mounted in front of the paper tape panel, and is small enough there's lots of mounting location possibilities on that panel. 

It does take it's own 5V power (no vampire off the Pi) which is another reason I bought it, as I put a power bar on the rack stand so it's easy to power the HDMI off some USB charger.

There are two HDMI Inputs (full size) and two spots to plug in the USB touch interface. It has a stand but is also designed to attach a Raspberry Pi directly to the back if you were building that kind of system. 

Frankly, I think its' kind of awesome. Maybe tomorrow I'll plug it in and give it a test, then make a template to help me drill mount holes and attach it.

-R