Picture of Mac OS Foot Switch from a Guitar Amp Pedal.
Need a foot pedal for your Mac? Got a two switch guitar pedal and and arduino board lying around? A couple of wires, a three prong 1/4" jack and you're all set. I had to do some audio transcription and used my pedal to play/pause and skip back the video.

This tutorial illustrates making a foot pedal for a Macintosh computer using an Arduino and a 2 switch guitar amp pedal.

You'll have to be a little familiar with soldering and writing simple code.

If you need a guitar amp pedal switch, you can buy one or make one with this other instructable or with this one.
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Step 1: Supplies.

Picture of Supplies.
1) Guitar Pedal (I'm using a two switch pedal)
2) Arduino (I'm using a Diecimila)
3) Breadboard (or prototype board if you like)
4) Three Conductor 1/4" Stereo Phone Jack (got one at RadioShack)
5) 2 1k ohm resisters
6) Wire (you know whatever you have lying around)
7) Soldering Iron (and Solder will help too)

Step 2: Solder the Jack

Picture of Solder the Jack
The jack (and corresponding plug) has three connection points: Ring, Tip, Sleeve. You need to solder a wire onto each of the connectors. Make the wires different colors just to stay sane.

The Sleeve (attached to the black wire in my photo) is the common line running to each of the switches on the pedal. If we give it (the black wire) a voltage, switch #1 will turn on/off the Tip wire (green in my photo). Likewise, switch #2 turns the Ring on and off (yellow in my photo).

If you get confused (I kinda did) just solder a different color wire onto each lead on the jack. You can use a volt meter to test for continuity (or wire it up to the breadboard with an LED on it) to figure it out. I kinda looked at each lead and figured out what part of the plug it actually makes contact with.
nifty! would love to see a video of you using the pedal at the end :)
aymans (author)  leahbuechley6 years ago
Glad you like it! I added a little demo video as step 12.
RetroTechno4 years ago
This is a pretty good intro to what is possible with an Ardurino and a Mac. I think I will find myself coming back to this for reference.
ninjabob74 years ago
I did something similar with an old USB joystick. Basically I just ran wires from the footswitch and soldered them to where the joystick buttons were. Works great for a 2-button switch, though I'm having some electrical issues trying to add another button. Are there any advantages to the Arduino (besides the possibility of analog inputs?)
aymans (author)  ninjabob74 years ago
The Arduino lets me talk serial over USB to the mac. So adding new functionality is simplified (hardware wise) but requires a bit of software legwork.
blackwellj5 years ago
i have found a progran called apple script proxy which is much simpler and works with no need for 2 apple scripts or command line
blackwellj5 years ago
steps 8 9 and 10 all the downloads are .tmp files and dont work properly if i right click on them and save as (i am using mac obviously)
aymans (author)  blackwellj5 years ago
So, most of the code is not in a 'ready to run' state. The code in this instructable illustrates a proof of concept. You have to compile the C source (as said in Step 9) and modify some AppleScripts (as said in Step 10) and assemble the App (Step 11). If you Save As... the code on Step 8 and name it .PDE, that should open right up in the Arduino app and print out the button number to the app's serial console.
blackwellj5 years ago
sorry that diddnt work all i got was a copy of the page i am on opening
aymans (author)  blackwellj5 years ago
if you tell me which code you are trying to download from which step (exactly) i could provide more assistance.
blackwellj5 years ago
file downloads dont work and i want to make it:(
aymans (author)  blackwellj5 years ago
hi blackwellj, which step are you trying to download the code for? -a.
the arduino code and the mac codes all of them they just come up as a .tmp file and open a blank tab thanks for the quick responce james
aymans (author)  blackwellj5 years ago
You can hit Control and Click (or Right Click) on one of the files and say "Save Link As...". Save it as the right filename like 'footswitch.pde'. That should download it correctly.
woodythdog6 years ago
Hi nice job I hope you don't mind answering a low tech question for me. What is the pinout for you Vox footswitch I assume its something like this can you confirm? Thanks
vox footswitch.JPG
aymans (author)  woodythdog6 years ago
Yup, that is correct. I run the + current to the sleeve and measure/test for current at the ring or tip.
thanks unfortunately I don't have a footswitch to ring out in fact I am planning to build one for my VOX amp and I have been having a hard time finding a schematic online.
me too mate. this drawing is right though. tip switch controls reverb, sleeve switch controls tremolo. closed circuit means effect is bypassed, so if you get two dpdt footswitches you can rig up a status LED for each effect
MisterHay6 years ago
You could also accomplish this by wiring the foot switch to the controller of a USB keyboard. I've built one for controlling PowerPoint shows where the right switch connects to the pins for PgDn and the left to PgUp. Yours is more impressive (and reconfigurable) though.
I built a synth controller using this technique. Works great for switch-type events, especially if you can make it work for keys that you don't normally use in your sequencer. I did it by taking apart an old USB keyboard and hooking up alternative buttons to the switch points, basically like what's described here:

The cool thing about aymans hack is that he could pretty easily add some analog foot pedals to the mix, since Arduino has 6 analog inputs.
aymans (author)  todbot6 years ago
Totally! I want to hook up a Cry Baby Wah and have it rotate my apps. :)
aymans (author)  MisterHay6 years ago
Oh cool - it wasnt obvious how to wire my Arduino to be a USB HID I went this route. Do you have an instructable on how you made your switch?
Some day I'll get around to actually posting Instructables myself, but the link that todbot posted is pretty similar to the device that I made.
todbot6 years ago
So awesome!