Raspberry Pi Hitches Ride Inside Vintage Terminal

When a dumpster dive yielded a vintage video display terminal, [dennis1a4] knew just what to do — bring the Heathkit H19 back to life and stuff a Raspberry Pi inside.

The early days of the personal computer era were a time of great market diversity. Everyone was making stuff needed to cobble together your perfect computer, and terminals were among the most important pieces of gear. Lear Siegler, DEC, Wyse — everyone was in on the game. Even Heathkit competed with its H19 serial terminal, which would have set you back a thousand or so early-1980s dollars.

The terminal [dennis1a4] found was DOA, but he quickly determined that a bad cap was shorting out the -12VDC rail. A little extra detective work was needed to get the terminal to both echo characters locally and output them over the RS-232 port, and bam, working terminal. But then what? Raspberry Pi to the rescue! But those old school +/-12 volts swings would give a Pi a bad case of Blue Smoke Disease. After a little voltmeter poking, and through the magic of socketed driver chips, the Pi was talking right to the terminal at a screaming 9600 baud and accessing the Hackaday Retro site on the 80-by-24 mono display.

All in all, a nice hack on a piece of computer history. But just one question: Can it play Doom Flappy Bird?

41 thoughts on “Raspberry Pi Hitches Ride Inside Vintage Terminal

  1. Carefully looking through the amazing collection of projects at hackaday.io, we can find another such great terminal with even smaller dimensions – and with color CRT tube – also powered by Raspberry Pi:
    Some pictures:
    https://cdn.hackaday.io/images/999511464565599489.JPG https://cdn.hackaday.io/images/2086691464574987032.JPG


  2. I built one of those terminals for work back in the ’80s. The logic board was pre-assembled, but there was enough left to assemble in the monitor and power supply for them to call it a kit.

    1. Heath also sold a CPM computer, the H89, which was basically this terminal plus a Z80 computer board in the same case. You connected the computer board to the terminal board and had a complete system. There was an alternate front panel to the display to hold a 5 ¼” floppy.
      I had an H89. Shortly after I bought my first PC clone the H89 CPU board died. I didn’t have much use for a CPM box anymore so converted it to a terminal which I used for several more years.
      It was not a bad terminal for its day, but the keyboard left a bit to be desired.

      1. I’m getting an H89 back up and running right now. More than a few tantalum capacitors have “chosen a new pope”. The keyboard on mine isn’t bad (no where near as bad as the H9 terminal keys).

      2. There was an alternate front panel to the display to hold a 5 ¼” floppy.

        The best bit? Hard-sectored floppies with a synchronous receiver/transmitter instead of a floppy controller.

  3. In general, serial terminals are underrated. For a year or two, I hooked a tvi 928 (? I think) to a 28.8 external modem and connected into a unix box and was able to happily develop software with the magic of screen. Multimedia ultimately doomed them, but it’s a sad thing to leave behind something that was so rock solid.

  4. Some people have all the luck as I never found something like that thrown out just boring P4 era PCs and old copiers.
    BTW if you ever need to hook up a pi to an old device like this try using the Max232 chip it handles all the voltage conversion.

    1. Right!? Since my move I have lost my ‘route’ of dumpsters that sometimes yielded cool junk. Never anything like this though. Mostly broken modem testers and communication switches of various designs. I did luck out once and find the shell of an Amiga but alas no guts. Yes, I did keep the shell :D

  5. It’s funny how so many people finding these or other terminals laying about think there has to be something wrong when the serial output is +/- 9V or so. We have a current generation who has never seen a proper RS-232 implementation and simply thinks the 0-3.3 or 0-5V async serial is ‘RS-232’.

    I’ll bet the H19 with a Raspberry Pi is one hell of a usable computer.

      1. It’s better than having your own personal VAX.

        Been there, done that. No it’s not.

        VAX-11/780, VT-100, four RM05s all to my lonesome. Talking to an embedded PDP-11/73 via a DR-780.

    1. Yes the RS-232 does specify the line voltages so the newer 3Volt and 5Volt Serial are not actually RS-232 even if they share the same logic protocols.

      The other thing that I often see is single TX/RX implementations that have none of the handshake signals like CD DTR DSR RTS CTS ect. These are not RS-232 either even though their RX/TX protocols conform to the standard.

  6. For no good reason I want a toggle switch to switch between the RasPi’s composite video output and the terminal’s output.

    No good reason, of course, because it mostly defeats the purpose of using a dumb terminal to interface to the RasPi…

      1. The VT220 had a composite video input that it would superimpose its video over … only problem is that the external source was responsible for genlocking to the VT220’s composite output.

          1. I have a VT131, is it hard to get composite video on hacked to this thing? I’m a gamer, and TXT-based are kind of interesting, but I would want to play some more advanced 3d games in greyscale instead of attempting to utilize the odd vintage computer hardware in this.

  7. Here’s the fun exercise left for dennis1a4: try running vim on there, and see how it renders. If you get something other than about a line of garbage characters, I’ll be surprised.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.