• So you want to build your own (cool!) or help us improve our products (even cooler!)? Well, this is the place to get started. For the most up-to date information, check out our page on

    Google Code

    Upgrading Firmware:  Our guitars all come with a method to re-program the firmware via USB.  This means you can easily mess with the code, and we can also add features to your guitar as we develop them!  Basically, you hold down the “Plus” button, plug it into the USB port, and use some special software on the PC to upload the new firmware onto the guitar.  There’s more detailed instructions here, though.

    Troubleshooting: Having issues getting your guitar to work?  A good place to start is the Troubleshooting page on the forum.  If that doesn’t help, post it on the forum or e-mail us, and we’ll do our absolute best to get you on your way!


    We’ve got an instructions page here, although the process is pretty simple.    We’re looking to improve them, so if you’ve got any feedback, please let us know! For that, and if you have any questions, go ahead and e-mail us at develop@openchord.org.


    If you’d like more information about how to help out developing with us, contact develop@openchord.org

    Also, look over the the Instructables and the new instructions,  since that will hopefully give you a better idea of how everything works together. There’s also more nitty-gritty information available on Google Code, including all the code for the Wii and USB versions.

    The V1 is currently being developed on the Atmel ATMega 328p chip.

    We’re currently working on the following things, more or less in order of priority:


    • Product Testing – We’re always testing.  We want to know how to make things better!  Are the play modes intuitive? Does switching between modes and programming new button patterns make sense?  Is it fun to play with?

    Hardware / PCB Design

    • EMI Reduction – If anyone knows things about reducing Electromagnetic emissions, let us know how our boards can be improved!  We’re looking into FCC testing, but don’t want to waste our money with a poor design.


    • Videos – We need some more videos of how to use the guitar and general play footage.  Especially more professional-style advertisement/product demo video would be amazing, but any video at all would be great.
    • Images – We could use some promotional materials, banner ads and buttons, that sort of thing for spreading the word.


    • Feedback – We’ve got a set of instructions on how to use the guitar here, but we’d love to get some feedback as to the understandability of it all.

    New Functionality

    • Vibralto - By attaching a vibration sensor at the head of the guitar, replace the whammy bar’s functionality by measuring vibrations in the guitar neck, allowing for a more realistic playing effect.  However, we haven’t thought of a good, cheap vibration sensor yet… If you know anything about vibration sensors at all, or have some other great way to implement vibralto, please, let us know!
    • Strumming – So we got some copper tape and used it to make some conductive picks that are wired to the guitar, and they seem to work OK.  However, they have issues, since touching the pick is interpreted as a contact, and a wired solution isn’t ideal.  We’ve thought a bit about IR sensors by the strings (unreliable, kinda slow) and motion sensors (kinda imprecise, expensive, big), but this one is probably the trickiest part, since the strum command needs to be both quickly responsive and accurate. So if you’ve got any brilliant ideas, let us know! Good luck!


    • Code Review – Our code is now doing pretty well for the Wii and USB / PS3, but some review would always make it better.
    • More functionality – It should be pretty easy to take the V1 and turn it into a basic MIDI guitar, among other things.  Also, if anyone is familiar with MAX/MSP, I’m sure there’s a bunch of cool things that could be done by interfacing with that.
    • Porting the code to the Arduino – This should be pretty easy, since now we’re using the same chips. Things might need to be refactored and changed a bit (pin numbers, etc.) and put together in a neat little Arduino-friendly package.
    • Expanding to the Xbox 360.  This one is likely not going to happen anytime soon, since nobody has figured out how to get around the security on the Xbox 360 controller.  It seems like all current controller hacks are based on using an existing controller, which is fine, but is more attuned to the L-Series than the V1.

    And just a few legalish things:

    The design specifications are licensed under the Creative Commons Share-alike license, and the source code is licensed under the GPLv3. This means you’re free to edit, modify, and republish any of the instructions provided, so long as you acknowledge the documents’ authors and OpenChord.org. If you modify any of the source code, you must freely distribute your modifications alongside any redistribution of the software.

    Also, like the Arduino project which this project is based off of, OpenChord and OpenChord.org are trademarks of OpenChord.org. If you’d like to produce guitars, please contact us if you’d like to use the OpenChord name.