You should check out the S.F. Bicycle Music Festival http://bicyclemusicfestival.com/ They cycled from San Francisco all the way to Vancouver, B.C. with bands and a bicycle powered PA system. I caught them here in Seattle and helped broadcast a singer in a cargo trike during a parade over my bike sound system via FM transmitter. They set up 3 stationary bikes attached to generators with ultracaps to power a PA system for shows in parks and wherever. I didn't have my 12" JBL subwoofer bike system with me at the time, but it requires a lot more power than my legs can put out :) --Joseph On Thu, Mar 4, 2010 at 1:48 AM, Jonathan Gazeley <jonathan.gazeley@xxxxxxxxxxxxx> wrote: > Morning LAU, > > As I cycled to work this morning, I had a crazy idea. It's just > daydreaming and will probably never happen, but I wondered if anyone on > the last has any useful/interesting thoughts. > > I want to measure how fast I'm turning the pedals on my bike (the > "cadence") and synthesize/sample the sound of an internal combustion engine. > > As far as I can work out, there are three major parts to this. > > 1. A sensor that can measure my cadence. A simple magnet switch that > triggers once a revolution won't be enough to measure the cadence with > sufficient resolution, since my cadence is usually between 50 and 80 > rpm. I would probably need to mount multiple magnets spaced equally > around the chainwheel and have a single sensor on the frame. Then I have > to get it to supply this information to my control program. > > 2. I need a control program that can read in the input from my cadence > sensor and convert a cadence reading of "66 rpm" into a frequency that > should be sampled/synthesised, e.g. "500 Hz" (I'm making these numbers > up). It will also need to be able to somehow smooth out the readings, > perhaps by interpolation, so when I accelerate, the sound of the revs > climbing doesn't increase in obvious steps. It could also have other > logic, e.g. when my cadence is 0 rpm, the sound of the engine is idling > rather than off. > > 3. I need a synthesiser or sampler that can take an input from my > control program and make the sound of an engine (or more likely, a sine > wave to start with). I've never sampled or synthesised on a computer > before but this engine-specific sampling technology already exists in > video games, such as torcs[1]. > > I have absolutely no idea why I would want such a device - just for the > fun of building it, I guess. I would like it to work in realtime (rather > than later generating the soundtrack from recorded cadence data). The > thought of sitting at the traffic lights with my earphones in and then > hearing the mighty roar of a V8 as I pull away would be really satisfying... > > [1] http://torcs.sourceforge.net/ > > Any thoughts - useful, interesting, humorous, or otherwise - are welcome! > > Cheers, > Jonathan > > ---------------------------- > Jonathan Gazeley > Systems Support Specialist > ResNet | Wireless& VPN Team > Information Services > University of Bristol > ---------------------------- > > _______________________________________________ > Linux-audio-user mailing list > Linux-audio-user@xxxxxxxxxxxxxxxxxxxx > http://lists.linuxaudio.org/listinfo/linux-audio-user > _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
