IBM Model M Keyboard Conversions
Custom USB Conversion
These keyboards were built in the 80s and early 90s when USB wasn’t around. They used a serial terminal connection on the M F1 122 key varieties, and PS/2 on the 101 key standard Model M. These connections are almost never used anymore, so I convert them to the modern USB standard based on Soarers Converter. This allows these behemoths from another time, to be used with modern computers; you can even plug them into tablets and micro computers like the Raspberry Pi
Creativity, Hacks And Modifications
The amount of room inside these keyboards; combined with the type of crazy person who wants a keyboard so big and heavy, that they could kill someone with it, leads to a wide variety of hacks and modifications that are done to keyboards like this: Security tools hidden inside, stuffing a Raspberry Pi inside a similar keyboard, converting to Bluetooth, and many more. This makes the Model M (my favorite the Model M F122) a GREAT platform for mods and tricks.
Model M 122 Key Keyboard – Internal Soarers Converter How-To
This guide is to help you do your own conversion from the ancient terminal serial bus connection that is on these old keyboards to the newer USB standard using Soarers Converter, (which is a small dev board called the ‘Teensy’ running custom firmware originally developed by the geek hack user ‘Soarer’) that will be connected inside the case of your IBM Model M 122 Key Terminal Keyboard.
When you are finished, you will have a keyboard that you can plug into any computer with USB (pretty much all computers made today) and use just like any other keyboard. It will also have the ability to be re-programmed so that you can assign and re-assign keys at will. The great thing about the M122 is that it has lots of extra keys to assign to functions. You can for instance set it up so that when you push the F21 key, it will automatically type your Email address. no more typing out your own address into all those forms. Just punch one button, and bam! there it is.
You will need the following items for this project:
- IBM Model M 122 Key Terminal Keyboard (This can be identified from a standard Model M easily by the double row of function keys on the left side)
- Teensy 2.0
- USB Cable A – B
- Panel Mount USB Cable
- Soldering Iron & Solder
- Command-Strips, or other double-sided adhesive foam mounting square.
- miscellaneous hand tools including screwdriver, 7/32 and 3/16 bit-driver and wire cutters.
- Box-cutter, or very sharp knife.
Teensy 2.0 Dev Board
This is a very small Dev board that will cost between $15 and $20, from most electronics suppliers, it is able to ‘pretend’ to be a standard USB keyboard, (or other device) so it is used very often for Keyboard interface projects. It can be programmed using C or Arduino code. I will walk you through this process.
Panel Mount USB Cable
This cable will connect to the teensy 2.0, and be mounted inside the keyboard case, allowing you to use a detachable cable for your keyboard. It is technically possible to do this modification without this piece, but I think you will agree that it gives the project a much more professional appearance. It is worth the $4 it costs. Seems to only really be available from Adafruit, get it together Sparkfun! 🙂
- Start with your Model M 122 Key Keyboard.
- Find a good work surface and gather your tools.
- Take wire cutters, and snip off the keyboard cable about 1/4″ from where it protrudes from the rear of the case. You are committed now!
- Begin by removing the three screws along the bottom rear of the case. This will take a 7/32″ deep well socket, or nut driver.
- Sometimes these screws won’t want to come out easily, you may have to tap the top of the keyboard to get them to drop out after you have unscrewed them all the way.
- Once the top case is off, lift up the keyboard assembly plate, and unplug the small black connector that plugs into the circuit board.
- Remove the small rubber grommet, and pull the wires out of what remains of the cable sheath.
- Now that you have the base of the keyboard case empty, you can take your bulkhead connector and test-fit it into the far opening. It should be pressed down as far as it will go, so that the little ears are pressed down between the little plastic pins.
- The orientation should be like the picture on the right.
- Mark the holes for the bulkhead mount, I used a mechanical pencil with the lead extended.
- Then go ahead and drill the holes out and test fit, but don’t tighten it up yet, you have to make it look nice first!
- To do that you will need some super glue and your soldering iron should be heating up.
- Take the small plastic insert that held the cable grommet down, and cut the ears off with a sharp knife, or even a good set of shears. You should cut on the lines as indicated, and when you are done you will have a flat piece that fits back inside the hole, leaving just enough room for your USB/B cable to fit inside.
- Now use super glue and glue the piece in-place like the picture on the right.
- Take your soldering iron, and ‘weld’ the plastic edges together on the inside of the case, so that this piece can not move. The reason I take this extra step beyond just gluing it into place, is to prevent it from popping loose and falling out. There can be a lot of force behind someone pushing a USB cable into this hole, and if they are a little off the mark, it could break the glue bonds.
- Now screw the bulkhead connecter to the case, and admire your work! You should have a result much like the picture on the right.
Now solder the old cable connector to your Teensy. This pinout guide will help you solder the wires to the correct pins. When you are finished, it should be like one of the Teensys on the right.