Raspberry Pi Finds Itself Inside A TRS-80 Model 100

This TRS-80 Model 100 is a lot more powerful than you might think. That’s because [Karl Lunt] is using it as an enclosure for his Raspberry Pi board. Since the ARM-powered device comes sans-enclosure it’s fun to see a retro choice like this one. And having had to go out and buy a USB keyboard to use our own RPi, we appreciate [Karl’s] solution for using the original keyboard as an input device.

Above you can see that he’s using an LCD tv as the display. For now that connection is made using the composite video output, which explains the fuzzy image. To the right of the TRS-80 a standard wall wart connects to the barrel jack to provide power. [Karl] scrapped a USB cellphone charger in order to connect from the barrel jack to the micro-USB jack on the Pi board. The ribbon cable to the left lets him get at the I/O header without opening the case.

In order to use the keyboard he patched into it with a Teensy board. That connects to the USB port on the RPi, sending HID keyboard commands based on what it received from the user. We like this option as it give you the ability to pre-process keystrokes (ie: you can code your own custom macros that the Teensy will listen for). Right now the Model 100’s LCD screen isn’t hooked up but he may add that in the future.

18 thoughts on “Raspberry Pi Finds Itself Inside A TRS-80 Model 100

    1. That’s right, only seven exist. Take a close look at that post, all the pictures of the Raspberry Pi are closeups of one of those seven, currently in a non-disclosed location. The rest of the post and project is an elaborate hoax to make you think someone actually managed to get one of these devices.

      1. Yea, I got mine on Monday and it looked it was run over. I have pictures on my blog if you click my name. I got it from Newark. I should get another one, these are so much fun. I have lighttpd with PHP and a PHP file manager running.

      2. I got two of them from Newark (Element14) which were in bags inside of boxes. And their shipping was sufficiently padded. Either way both units I received powered up with no issue and survived initial smoke tests. Would be all kids of awesome if I could find an XBMC build that was actually stable; or if someone would put out a debian build with a 2d accelerated xorg driver rather than the slow framebuffer one. Still, they work. w00t!

  1. I’m thinking the right way to fit it in a M100 or M102 is to unsolder the DB25, and put in a USB-RS232 connection on the raspberry pi, and usb ports out the back of the M100. The USB-RS232 connects to the 100’s RS232, and the pi has a getty running on that port. Then you still get the internal display of the 100.

    1. I would have liked to have seen that done.
      It would have kept both machines functional, but I don’t think you can stuff it all new parts into the original case without gutting the old hardware first.

  2. The M100’s display form factor is the only thing that has kept this from being done for real. I’m not sure chopping them up to use the keyboard is a very good idea, but to each their own.

    In fact, it’s an excellent enclosure for someone wanting to build a laptop style device, as the battery bay used very large cells and it could probably run a low power device for weeks.

    But I don’t think any modern LCD matches the old LCD’s measurements well enough to provide a drop in replacement. I’m guessing this guy might at well put the unit in a TI speak and spell.

  3. Someone should build an interface for one of those old 11″ laptop screens and make a PiPad.

    Ought to work, many of these old screens work fine if the equally antique CCFL is ripped out and replaced with LEDs.

    Some older digital picture frames used a VGA input screen without the e2prom memory, which should be useable with minimal modification.

  4. I picked up three Husky Hunter 2 units from a clear out of the basement at work, was gonna ebay them but may have to keep one, see if I can replace the guts with a Pi (already on order) and a WiFi dongle and use it as a remote terminal instead of my phone. Does anyone know if this is likely to be possible? Especially hooking up the Pi to the inbuilt display (40 x 8)? My hacker skills are limited but growing and I bought the Pi without a specific project in mind but this has piqued my interest. The enclosures for these units are virtually bombproof!

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