Measure Rover Speed

[Dominator_Legen]

Hy,

i'm using a 4 DC Motor to move my rover, and i need to measure the speed of my rover , i.e. the distance that the rover move, i heard about a fotoreflector sensor, dose this sensor do the jop, and if there are another sensor, what is it?
and how can i interface it to my pc, i have an interface card, from velliman (K8000), which allow me read an analog value from 0v to 5v,?

Please advice me..

Thanks in adavnced for whatever help.

[sanddrag]

A photocell type sensor is one way to do it. You could also use infrared leds and receivers, or you could use quadrature shaft encoders. I'm not sure how you would hook up any to your PC.

[Al Skierkiewicz]

John,
Most teams use some form of sensor that counts wheel rotation or fractions of a rotation. These can take the form of an optical sensor that closes a contact each time it sees a change (from light to dark or dark to light) and a segmented field, mounted on the wheel. Two such sensors, on a wheel with eight black and eight white segments (16 transitions in 360 degrees) can give you accuracy down to 1/4 of an inch (under a cm) and direction information. Teams were given gear sensors in their kits this year that also did a nice job as well but you need to have metal gears and a place to mount them. In either case, they are not an analog output. They produce digital pulses which can be read by any digital input.