read rpm from a dynamometer

hello! I'm building my own dynamometer for motorbikes. I'm about to buy the Arduino Duemilanove USB board with ATMega328 microcontroller.

What I can imagine is if I can use a inductive picup to pick up signals from a toothgear mounted on the drum (which is supposed to be accelerated).

I need the rpm to calculate the acceleration, power and torque and make a graph out of it

what kind of hardware would suit my needs?

Thanks :)

How about a magnet and a hall effect sensor? That’s how RPM is typically read, and it’s very easy.

yes that would work too i:) I'm totally new in this, so any suggestions and tips are appreciated. du you have any links to products that would work with the device?