Help with Length Measurement Design

[aviator91]

Hi All,

I have a need to build a device which will count (mm, cm or Meters) length of line or cotton coming off a reel.

I am assuming that I can use a microcontroller for this project??

The idea is that the string is stripped off the reel using a small DC motor. As the string is stripped off this reel, a sensor circuit would count the revolutions of the pinch roller mounted on the DC motor and use the PIC16FXX to convert this signal into a measurement on a small LCD screen.

As this is still a concept, I was hopeful that maybe someone might give me a good starting point or point me to a similar design which has already been posted.

Appreciate any input on this project.[/b]

 

[bobcat1]

HI

Using the PIC count the number of revolutions dubel it by 2*PI*R and you have the length

were R is the radius of the reel

Or you can measure the reel perimeter and doubel it by the number of count you get

All the best

Bobi