8) How Does the Pedal-Powered PA Work?

History
The concept of pedal power isn't new; people have been generating electricity with pedal power for decades, and even using it to power their PA systems since the 80's (most notably Bart Orlando and the Campus Center for Appropriate Technology at Humboldt State University). What hadn't been created until recently however, was a system light enough to actually be carried to a location by the same bicycle meant to power it. Before this point, all pedal-powered systems were either made from modified exercise bikes or bike training stands, or else the contraption meant to be attached to the road bike was much too heavy to be practical for anything other than home use.

In the summer of 2006, Nate Byerley, a.k.a. the Juice Peddler (www.bicycleblender.com), and co-founder of Berkeley, CA based Rock the Bike (www.rockthebike.com), led the effort to create a simple, powerful, portable system. The prototype design was launched in April 2007 for SHAKE YOUR PEACE!'s 600-mile rock & roll bicycle tour of Utah.

In late 2007, Dante, the engineer of the Ginger Ninjas, with some collaboration from Rock the Bike, launched an even more advanced system using li-ion batteries, solar panel plug-in, ability to be hooked into other bikes, and a lever that a band member can flip to engage the generator when they're speeding down a big hill, to store up electricity for their soulcycle.

How It Works In A Nutshell
How it works in a nutshell: a bike is wheeled next to, or onto the stage and is propped up on two rock-sturdy kickstands which elevate the back wheel so it can spin freely. The back wheel of SHAKE YOUR PEACE!'s bikes are unique in that they use a frame extension called a FreeRadical made by Xtracycle, that moves the rear wheel back 18 inches from where it normally sits. The Xtracycle also has a rack of lightweight metal tubing that surrounds the back wheel (which, by the way, can carry up to 200 lbs. of camping gear, CD's, food, water, and music equipment). Hooked to the Xtracycle is a 12V permanent magnet DC generator that can harness the momentum from the back wheel when it spins. An audience member mounts the bike and begins pedaling at a normal pace. Within moments the system is up and running. The current travels from the generator, to a 15V ultra-capacitor, then to a bridged 2 ch. 400W peak car-amplifier, then to an Eminence CH2010 10" hemp woofer, and a piezo tweeter (with an L-pad). The voltage is regulated by the pedaler, who watches a simple readout velcroed to the handlebars in front of them. (I'm going to build an Instructables.com tutorial at some point, I know this isn't detailed enough for a DIY guide. Soon...)

Interesting notes:
- The pedaling does get a little harder the louder and more bass-heavy the music, but never harder than a steady push.
- The music doesn't fade out if somebody starts slowing down, or get louder if the person pedals harder. The way it works is the system is either on or off - no inbetween.
- Depending on what kind of music is being played, there's a 1-10 min. buffer (1 minute for screaming rock, 10 minutes for a lullaby) between an audience member stopping their pedaling, and the PA going silent. In other words - an audience member doesn't have to be pedaling the entire time for their to still be juice to power the music.

For more questions regarding the system, contact us: syp@shakeyourpeace.com, or Rock the Bike: paul@rockthebike.com