Real guitar controller mod
by Bavi_H, 8/14/2010
The OpenChord.org guitar controller starts with a real electric guitar, then adds wiring to the metal strings, wiring or conductive tape to the metal frets, and a wired, conductive-tipped pick to create a scanning matrix. All the wires lead to a circuit board that converts the fret and pick inputs into appropriate fret and strum controls for Guitar Hero, Rock Band, or Frets on Fire. The controller can connect to a USB cable or a Wii Remote for use with a PC, Wii, or PlayStation 3.
![[OpenChord.org guitar controller]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZJOO6Gt4AvT47z-dDOoHXzxkQNX_sLvpuCHcYgTbLEqwl0_VRRVSomWBXgmDtIViO0MN-bZIPfswkSuorhum1gg6Zy6CyixbJS8QddVkfJDJTdxTNkb3PZooa0C4-39zJmCUEAg/s1600/intro.jpg) |
| the OpenChord.org real guitar controller (still from the intro video) |
![[wired strings]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvuewe16V_JuclIdylEP1ebB_qq_O6kfyg97mkCLH7HhgLoK2b3iYdS-yB48qMRH5Gps8wQHPdycZNJ7taepEK5TtSzrnbzDEO39zMgN6lPrDTb57oUCV_5r9zk-zkhvWE2oqiKw/s1600/1-wired-strings.jpg) |
| wired strings (photos from the build instructions) |
![[wired fret]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh6pxazlP264XnaQQjMspQMYTkNQvvHffKsftGr95EL5l2D94rwU-DZhiJ8puflw3qJHQGJDvLab-joKp2XC3PGlYTMDoVBygV4enu0F_ryPDOlaabZqBtaqqdGUEVibASD4BDG6w/s1600/2-wired-fret.jpg) |
| The frets can be connected with wire... |
![[taped fret]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjZ1Y26cPDXFPKpT1SWC7vsGOpDU1_P6_l1u98awrVWCyFFAgum4he2BbeHR0V6d6MNgW8QMk5loie0hkmkplTndZl524YBOGYLMUzAS13L4NdXSY2TDwfcI2t3XoPymowXkQDjZA/s1600/3-taped-fret.jpg)
![[copper tape traces]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhWgn7ePcAHe6fYC8uPpdhbhxm7I4HWdFbnpYRxdPfMvrQwz_u5XHkY9GRbCNnedY_QnD2anRCqeZz4koBzG_A7Uu4BUxtor70RADXoi801_5F4flW3uQSUzrtoyK9u1WcYWwYUKQ/s1600/4-copper-tape-traces.jpg)
![[tape meets kit]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEit8JEc8uccjAqZHFeCZ_UnN5Z-jkLvAohxGsAMJU41IlWkDrD31HvQWp__0F6NQK2yHY6txCawdtJIa7XmYyCat560n2HYaZ69bT2-r0aFNfuasgZQx_1hRspqyTO1zPEk3H8hkg/s1600/5-tape-meets-kit.jpg)
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| ...or with conductive tape. |
![[wired pick]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjcec4yYx5M2Ijb-fZbebn88otXdhSFviJAPOk2LCYEX7jEJ1NMX5EMy-0ZBR9Nk0v_2z-yjhKa7lUey9dyRmAhntH-HUAgrE9d__xo3K0eNhAvdtkXYQNf2SwkiZGwHI3mm6lbSg/s1600/6-pick.jpg)
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| wired, conductive-tipped pick |
![[scanning matrix example]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgLqpPf_0-09Hb5TDl9DP_Fe9sXqAlijFiRLFBjuws2mUd3EPSVr_5VywGbMIki0lUJpjP-UL2TM4xK5GCCEhxjegYVdVXj4i2jQrdWHNbs8fqDm69vRmWaLKNtkKMX04o2J1IOKg/s1600/matrix.png)
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|
an example of how the scanning matrix works (diagram adapted from the manual) |
Basic use
Guitar Hero strum bar
Touching the pick to any string corresponds to pressing the Guitar Hero strum bar. In menus, touching the pick to one of the three strings closest to the ground corresponds to a down strum; touching the pick to one of the three strings furthest from the ground corresponds to an up strum.
Guitar Hero fret buttons
- OpenChord Fret mode Fretting a string on the first to fifth frets corresponds to pressing Guitar Hero fret buttons. You must fret different strings to use multiple Guitar Hero fret buttons at the same time.
- OpenChord Note mode Guitar Hero fret buttons are assigned to specific notes, either fretted or open string. By default, the Guitar Hero fret buttons are assigned cyclically to notes in a major scale, but other assignments can be programmed using the controller itself.
- OpenChord Chord mode Guitar Hero fret buttons are assigned to chord fingerings. The assignments can be reprogrammed via the controller.
The manual describes how to use the controller in more detail.
Limitations
Like a keyboard matrix, the OpenChord.org guitar controller is susceptible to ghosting: some fret inputs are electrically identical, so the controller can't tell them apart.
![[ghosting example]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgj51RrFBARfqyr4mLDE3O3UdUI-KIW2l6DEL7W2sCxKBu7O12yJlyOJOWnn_Wz32f4MAgXWZqREZFOlucY6RInV_I2nGXkn5bp41rtUnqo2E039B7gkJPSWjv_LLs6OuXJo24lOg/s1600/ghosting-1.png)
![[ghosting example]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDoo6bERSznNhyhZN5aNfI3tfnn0XSpfZ4-NQM1SMEHiQRW_RWdK2ywIow-bYp7GgPyobFxaclVDdVoJwQGn4-O2Ki_mSxZeqA5zqjxXhjyOOwgjtFO7BILlPo3BZJSUUexyGufw/s1600/ghosting-2.png)
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| ghosting examples from the manual |
Availability
The controller is currently available in kit form. The developer plans to sell guitars with the controller pre-installed in the future, and accepts pre-order deposits. But due to low interest, the project is on hiatus while the developer works on other projects.
Links
OpenChord.org Open-source real guitar controllers
www.openchord.org
The main page of the OpenChord.org website.
OpenChord V1 Building Instructions
www.openchord.org/building-developing/buliding-instructions/
The building instructions pages, with pictures and descriptions of the building process.
OpenChord V1 Guitar Manual (13 April 2010) [PDF]
openchord-guitar.googlecode.com/files/Manual%20-%2013%20April%202010.pdf
The latest PDF manual for the OpenChord.org controller.
Keyboard Matrix Help - ghosting and masking
www.dribin.org/dave/keyboard/one_html/
An explanation of keyboard matrix ghosting and masking.
OpenChord.org Buy page
www.openchord.org/buy/
The OpenChord.org purchase page.
Hiatus
www.openchord.org/2010/06/hiatus/
The developer's blog post that explains the project is on hiatus.