Looking for a wheel speed sensor...

[Roger S. Cohen]

Chris Howard asks,
> 
> I'm currently building a data logger for a thesis project and I need a wheel
> speed sensor. I'm thinking of using a proximity sensor with a magnetic
> trigger on the front hub. Does anyone know of a suitable sensor and where I
> could get one from ? (I'm in Sydney but anywhere will do!)

How about real cheap and dirty?  Get a bike speedometer.  Today, for about $20
US, you get a magnetic pickup (and magnet - with mtg. hdwr.) and interface to a
LCD display which can be user programmed for wheel diameter.  Can read speed and
mileage (plus time and elapsed time, etc.) directly - or open it and interface
to your equipment!

Roger Cohen
72772.2212 at compuserve.com