Hardware

Parts List

Essential items:

• Teensy, or similar AVR breakout board
• Connector to suit your keyboard
• Some wire

Optional items, as desired:

• 3x LEDs
• 3x Resistors for LEDs (value depends on the LEDs)
• 2x 1k Resistors (for pull-ups)
• Box (optional, but recommended!)

You could, of course, mount the Teensy inside your keyboard and not even need a connector or a box!

See the firmware section for details of supported AVR processors and breakout boards.

Wiring Info

Connector	Breakout board
GND	GND
Vcc/+5V	VCC
Data	PD0
Clock	PD1

See PJRC for Teensy pinouts, or the documentation that came with your chosen breakout board.

Connectors

I wired mine to a PS/2 socket, and then use adapters to connect the others.

kbdbabel has masses of connector info. So much, that it can be hard to find the one you want!

So I've included the most common connectors used with this converter here.

Terminal keyboards usually have a 5 pin, 270 degree, DIN connector...

...or sometimes this 8P5C connector...

XT and AT keyboards use the same 5 pin, 180 degree, DIN connector and pinout, while PS/2 keyboards use a 6 pin mini-DIN connector...

Pull-up resistors

In nearly all cases, these resistors are not needed.

But, if the keyboard has a long cable, I recommend adding two pull-up resistors of 1Kohm - one between Clock and +5V, the other between Data and +5V. These can really help to clean up a dirty signal (see here).

LEDs

Optionally, lock LEDs can be wired up. Useful if your keyboard doesn't have them!
The outputs are active high (each pin puts out +5V when it wants to light the LED).
A resistor is needed inline with each LED. (The value needed depends on the type of LED, 1Kohm is a good starting point for modern high-brightness types).

The pins used differ between Teensy and Teensy++.

Teensy 2.0 (ATMEGA32U4):

Teensy++ 2.0 (AT90USB1286):