accelerometer

Guest,

In general you can't easily use an accelerometer to make a speedometer. You would have to have a very well defined starting velocity and time, a very accurate accelerometer and clock, and either a fairly short duration or an error correction scheme. This sort of thing is OK for spaceships, for example, but not practical for everyday use. Just use a speedometer.

Accelerometers are not speedometers. You could have fun experimenting though. Unless this is some sort of school project, why bother.

You can buy a bicycle speedometer, that can be calibrated to almost any wheel size, for under 5 bucks:

http://www.dealextreme.com/details.dx/sku.2682

You can actually build your own accelerometer for almost next to nothing:

http://library.thinkquest.org/2745/data/meter.htm

My first year at Wentworth U, in Boston, we had to build one of these for a lab. We took it up and down the elevator in the Prudential Center, (modest skyscraper), and on a subway ride. That was cool, but the 8 hour of math afterwards was no fun, (pre calculators).

Implementation of speedometer based on accelerometer for android AcMeter - https://market.android.com/details?id=com.a10 . If you have android phone