Model M Keyboard

First and foremost, you will need a Model M keyboard of course! For this project I prefer a "terminal" version of the Model M - these were typically produced for use with "green screens" and usually have an attached cable with a RJ45 style connector (it looks like a typical LAN network cable connector). These come in 101 key and 122 key versions, either one will work fine. Part #1392595 is a common part number for a 101-key terminal Model M.

I'll only be focusing on the terminal Model M keyboard for this tutorial - they are generally cheaper and easier to work with - but in case you'd like to try another one I did verify that the code works ok with a "normal" PS/2 Model M as well.

These are readily available on eBay if you are looking to purchase one (try searching for "model m keyboard rj45" or "model m terminal keyboard").
Perma-Proto Half-sized PCB

I'm going to mount the Arduino Micro and the Bluefruit used in this project onto a Perma-Proto PCB to make sure that everything stays in place and all of our connections remain sound inside of the keyboard. This is optional, you could definitely wire all of the connections point-to-point if you prefer. As it happens, there are standoffs injection molded into the shell of the Model M keyboard that are the perfect size for this cute little PCB.

Click here to purchase this from the Adafruit store
Arduino Micro

The brains of this project will be an Arduino Micro. In the Adafruit store there is one that has headers already soldered on, and one that does not come with headers at all. If, like me, you are going to mount your components onto a Perma-Proto PCB pick up the version with headers, or make sure you have some strips of header that you can solder on yourself. If you will directly wire your components together then grab the version without headers.

Click here to purchase WITH headers

Click here to purchase WITHOUT headers
Bluefruit EZ-Key HID

Bluetooth capabilities will be handled by the Bluefruit EZ-Key HID module. Since version 1.1 this module can accept raw HID reports as input over its serial connection, which allows for the fine-grained representation of the keyboard's state that is necessary for this project. Bluefruit 1.0 will not work, and Bluefruit 1.2 is required if you would like to implement "consumer" keys (such as volume and media player controls).

Click here to purchase this from the Adafruit store
USB LiIon/LiPoly charger - v1.2

This USB charger will suit our purpose well; it is a good size, has a default charge rate of 500mA (same as most USB ports on your computer) and has an onboard JST connector and matching cable included that will come in handy.

Click here to purchase this from the Adafruit store
Lithium Ion Polymer Battery - 3.7v 2500mAh

I've chosen a 2500mAh battery for this project, but you could substitute a smaller battery if you'd like as well. However the Model M has plenty of space inside to fit a decently sized battery, and the 30 year old electronics draw a respectable amount of current so the extra capacity is nice to have.

I've found that this size battery allows for approximately 24 hours of operation on a full charge.

Click here to purchase this from the Adafruit store
16mm Illuminated Pushbutton - Blue Latching On/Off Switch

This nifty switch is perfect as a power switch for our project; the LED is driven independently from the latching toggle switch, so we can use the switch as a power button and the LED can be driven by the state pairing LED on the Bluefruit module.

Click here to purchase this from the Adafruit store
Premium Female/Female Jumper Wires

These .1" jumper wires are perfect for connecting our circuit to the existing electronics inside the terminal Model M keyboard. The PS/2 connections that we will be utilize are conveniently available on male header pins with this spacing, so with these we won't have to solder directly to the original parts. You will only need 4 of the individual wires.

Click here to purchase this from the Adafruit store
Break-away 0.1" right-angle male header

Space is kind of tight inside the keyboard, and the strips of straight header stand up just a little too tall for our purpose. You could just bend some straight header yourself if you'd like, but everything seems to stay together a lot nicer when you have the right part for the job.

Click here to purchase this from the Adafruit store
Last updated on 2015-05-04 at 04.25.25 PM Published on 2014-05-06 at 10.06.42 PM