Here are my three solutions.
The common part: a system based on arduino with a combination of sensors (effect hall for
speedness, various effect hall for cadence, and an accelerometer). With all this
information, you can calculate and simulate an rpm signal.
to produce sound I think in various options.
a) project arduino buzzer. It's easy to produce sound with a buzzer, may be not very
realistic compared with a real engine. To amplify the sound, a parallel electronic
project: a microphone, a motorbike battery, loudspeakers, and the corresponding amplfying
circuit. (and a backpack).
b) it is possible to synthesize sound inside an arduino. I already made the experiment
that you can find in the documentation: from a small wav file, convert the information
into bits, and put them inside the small eeprom arduino memory. The interesting thing (I
did'nt tried), is to use external EEPROM memories, so you have more memory for bigger
wav files. Amplification is also necessary. (I'm in my smartphone and I can't post
the references).
c) with arduino you can produce easily serial midi messages. Connect the arduino to a
computer, and with ttymidi (alsa client) you can easyly catch the serial information and
redirect the messages to fluidsynth. Previously, with swami, sample a real engine. Try
with pitch bend messages a realistic acceleration. You will need also a backpack, and
depending ot the noise you want to produce, external amplification.
Notes:
-I think that the backpack will be compulsive, if you want to compete with real engines.
-ever that I say easily I mean that it took to me a lot of effort the first time.
Hope this helps,
Joan Quintana
www.joanillo.org