128 lines
4.7 KiB
Markdown
128 lines
4.7 KiB
Markdown
## Unicomp Mini M with Teensy2.0++ controller & QMK Firmware
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### Overview
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#### Goals
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The goal of this project was to replace the stock control board of the Unicomp Mini M with a programmable one. The Mini
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M was released by [Unicomp](https://www.pckeyboard.com) in Q1 of 2021 and is a re-release of The IBM Model M Space
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Saving Keyboard (SSK) with some enhancements.
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This guide strives to achieve the following:
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* Make completely reversable changes, or in other words, no permanent modifications to the Mini M
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* Allow full programmability of the Mini M via QMK
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* Be able to flash firmware without having to take the board apart to hit the reset button
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* Create a default keymap that works just like the stock keymap shipped from Unicomp, including the toggle-able number
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pad
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* Support all LEDs as normal
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My guide will go a few steps further:
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* Convert the wired connection from USB-A to USB-C
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* Install a potentiometer to dim the LEDs if desired
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#### Credits
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The following resources were instrumental to the success of this project:
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* Model M 101/102 write-up located in `qmk_firmware/keyboards/converter/modelm`
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* [Model M Subreddit](https://modelm.reddit.com)
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* Model M Discord
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### Hardware
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##### Parts
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For a working Mini M with QMK *without* LEDs working, the following parts are necessary:
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* 1 Adafruit Perma-Proto Full Sized Breadboard. Luckily, this board is a perfect fit for the Mini M case!
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* 1 Teensy2.0++, with headers soldered on if you can find it
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* 2 20-row x 1 column headers, if you can't find a Teensy with headers already soldered on
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* 2 16-pin Ribbon connectors, PCB mount
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* Hookup wire. I used 30AWG wire and while it worked, I should have used 1 gauge (or more) thicker
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* A panel mount male USB-B to female USB-C extender
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To get the Mini M working with LEDs, you will need:
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* 3 1kOhm through-hole resistors
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##### Tools
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The following were absolutely critical for the project:
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* Soldering iron, preferably one with a narrow tip for small connections
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* Drill, preferably a hand-held rotary tool (such as a Dremel)
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* Wire strippers/cutters
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* A sharp knife
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Optional, but worth having around:
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* Helping-hands, PCB holder, preferably both
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* Multi-meter for testing continuity of your connections
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* Hot-glue gun for mounting the USB extender to the Perma-Proto
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### Assembly
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#### Solder Teensy to the Perma-Proto
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1. Solder headers to Teensy
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2. Solder headers to Perma-Proto
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#### Solder ribbon connectors
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* Rows on the Perma-Proto that line up with membrane ribbons
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* Trim excess under board
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* Test continuity
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#### Solder in hookup wires
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* Ribbon connector used for the right ribbon will need hookup wire to establish connections to the Teensy
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* 12 required, 16 if you want full functionality
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#### Optional: Solder in resistors
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#### Caveat: D6 pin on the Teensy
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There are a few ways to mount the Teensy to the Perma-Proto board. I chose to connect my 16 pin ribbon connector to the
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Teensy pins starting at C7 and ending at D2. If you do this, beware that pin D6 will not work for the purposes of this
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project. It is possible to modify it to make it so, but that is beyond the scope of this guide.
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Bypassing D6 is necessary if you mount your ribbon connector as I have just described. Luckily, it is a simple process!
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First, with a sharp knife, sever the connection between your ribbon connector pin that is connected to Teensy D6 pin. I
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would recommend doing this at the closest possible point to the Teensy on the underside of the Perma-Proto board. Once
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that is done, use a remaining point on the Perma-Proto bus for that ribbon connection (that was previously connected to
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D6) to add a jumper wire connected to pin B7. If you are using the firmware files provided in this repository,
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everything is already set for this configuration.
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### Testing
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### Software
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#### Build firmware
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See qmk documentation on getting your build environment working.
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Compile the Mini M firmware files with the default keymap. It allows for the Mini M to be used with the same
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functionality as shipped from the manufacturer.
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```bash
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$ qmk compile -kb unicomp/mini_m -km default
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```
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While plugged in, press the reset button on your Teensy and then:
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```bash
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$ qmk flash -kb unicomp/mini_m -km default
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```
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If everything works to this point, congratulations! You now have a programmable Mini M. If you are using the default
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keymap, you can reset your Teensy by pressing Shift+Pause together, eliminating the need to take apart the case in order
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to do so.
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#### Keymaps
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To build your own keymap, create a new directory in `keyboards/unicomp/mini_m/keymaps/<your name>`, copy the files from
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`keyboards/unicomp/mini_m/default` into your new directory, and edit them as you wish. When you are ready to flash your
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new keymap to the Mini M, the command will be `qmk flash -kb unicomp/mini_m -kb <your name>`.
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