Dog Leash Optical Encoder?

[archer003]

Our team is planning on attaching a dog leash to a CiMple gear box in order to make an optical encoder.
Yes, that's right, a retractable dog leash.
The Box allows us to attach the encoder onto the shaft with ease as well as gain the ability to measure the height of our tower. Our programmers are planning on using this on the code.

I was wondering about opinions on this, as well as legality? I can't imagine a standard, off the shelf dog leash being against the rules, and I know but you never know. Thank you!
~M

[Justin Stiltner]

Assuming you are using a legal potentiometer, then whatever you attach to it is fine as long as it meets the additional hardware rules.

What you are making is commonly called a string pot. you can get potentiometers that have multiple turns, in that manner you may not need to use the gearbox. A normal pot only turns about 270 degrees, a multi turn pot may turn 10 or more times.

I have used celesco string pots before with good results. They were about $60 per each when we bought them, and would be more reliable and faster than making your own. Good luck!
http://celesco.com/stringpots/index.htm