Make: DIYSUPERHUMAN
Drop the controller and shred songs using the
electrical signals from your arm muscles.
BY ROBERT ARMIGER AND CAROL REILEY
We created Air Guitar Hero as a fun rehabilitation exercise
for people with amputations. Here we’ll show you how to
make an inexpensive version so anyone can play Guitar Hero
without pushing buttons. It uses an electrode cuff, a modified
Wii guitar controller, and open source code.
MATERIALS & TOOLS
Total project cost is about $500–$1,500 (not including
a computer), depending on whether you buy the electrode
amplifiers or make your own.
Nintendo Wii video game console
Guitar Hero III: Legends of Rock video game, Wireless
Bundle with Gibson Les Paul controller
DB9 D-sub connector, female, solder type #B000I-
21 YX2 at
amazon.com
RS-232 serial extension cable, DB9 male-to-female
item #02711 from Cables To Go (
cablestogo.com)
Laptop computer running Windows XP (32-bit version)
EMG electrodes, silver-silver chloride, bipolar ( 1 box)
We use Duotrodes, item #6145 from Myotronics
(
myotronics.com). These are consumables each time
you play; a box contains 135.
Button snap-connectors from any fabric store
Myoelectrode amplifiers ( 4–8) One per electrode pair.
The more electrodes you use, the more accurately
Air Guitar Hero can decode your finger motions.
Commercial-grade research units from Otto Bock
Healthcare and Liberating Technologies (#BE328) cost
about $500 per amplifier channel. As a DI Y alternative,
check out the Open Myoelectric Signal Processor that’s
being developed by Open Prosthetics, with 16 channels
of amplification for about $250 ($16 per channel!) at
openprosthetics.wikispot.org and
code.google.com/p/
myopen.
The cheapest option is to make your own bio-instrumentation amplifiers from op-amp chips, as
described on page 263 of Medical Instrumentation:
Application and Design by John G. Webster and John
William Clark ( Wiley, 1998, ISBN 0471153680). This
is how we build EMG amps for a robotics class Robert
teaches, and it’s also how MAKE Labs built and tested
the Air Guitar Hero system; for instructions and Eagle
circuit board layout files, go to
makeprojects.com/v/29.
This method costs only a few dollars for 4 channels.
Software:
Matlab version R2010b or newer, from Math Works
(
mathworks.com)
Matlab Data Acquisition Toolbox from Math Works
Matlab Signal Processing Toolbox from Math Works
Garry McLeod
44 Make: makezine.com/29
