On Thu, Mar 4, 2010 at 4:48 AM, Jonathan Gazeley <jonathan.gazeley at bristol.ac.uk> wrote: http://www.patentstorm.us/patents/6394875/description.html this is an available product, too. its not based on cadence, just wheel rpm's. a google for "bicycle spokes rear wheel sound engine simulated" gets quite a few similar hits. --p