I am an avid gamer and run a Teamspeak VOIP server to chat with my friends while playing World of Warcraft.  One of the short falls of using this application is that a push-to-talk switch is required to use it.  There is an option to use voice activated mode but that will transmit when ever a loud sound is present in the room, which in my case happens every time my dog squeeks his ball.

I was thinking about a solution to this problem that would leave both of my hands free to press keys that I need for playing the game and thought about a foot switch.  I have a friend who is a tattoo artist and asked him if he had any broken foot switches and he had one that he was no longer using.  The switch that he provided me with was a Linemaster 491-S available from Allied Electronics.

With the help of some folks at Milwaukee Makerspace, I found the USB development board called the Teensy from http://www.pjrc.com/teensy/.  This board can act as a keyboard and with the use of the teensyduino I was able to program the board using a simple arduino sketch.  The best part of using the teensy board is that it is very small and fit right inside the case of the foot peddle.

This project is barely scratching the surface of what the teensy and teensyduino are capable of but it is my first hardware hacking project.  I am glad that I started with something simple.

Build Log:

The original foot switch.

The foot switched disassembled and ready for hacking.

I desoldered the cable and attached the Teensy with two small sections of wire.  In my case I used pin 10 and the GND.

Another view of the Teensy attached to the switch terminals.

Here the Teensy is press-fit into the foot switch case.  I had to modify the original cord retainer by sanding it down quite a bit to get the board to fit inside the case.

Another view of the Teensy fit into the case.

The modified cord retainer is used to hold the Teensy in place.

A view of the USB connector.

Finished product.

Arduino Code:

I based the code off of Pete Prodehl’s Photobooth button but had to change the keypress to the control button and also clear the keypress when the peddle is released.

void setup() {
Serial.begin(9600);
pinMode(10, INPUT_PULLUP);
delay(4000);
}

void loop() {
if (digitalRead(10) == HIGH) {
Keyboard.set_modifier(0);  // clear keypress
delay(10);
} else {
Keyboard.set_modifier(MODIFIERKEY_CTRL);  // hold control key down
Keyboard.send_now();
}
delay(10);
}