Motorcycle Sounds For Your Bike
To fix this problem, SoundofMotion has developed a product that can add the sound of a roaring V-Twin motorcycle to your otherwise human-powered ride. The system uses a monitor on the bike to determine wheel-speed, which talks via Bluetooth to your cell phone to provide the sound.
Given that the quietest of motorcycle exhausts is going to be far louder than just about any cell phone speaker out there, it's somewhat doubtful that this device is going to help the rider get anything more than some bemused looks from nearby pedestrians. But, if you're looking to add a little humor to your ride, this might be a good way to do so.