Goodness, YES. Please get a copy of the rules. It explains a lot, and if your robot does NOT follow the rules, you will not be allowed to compete. Really, it is very important. - DonRotolo [more]
Here's a very simple way to use some PVC pipe sections and a couple of 2-liter pop bottles to make a beam scale to weight your robot. As the instructions state:
a) This is not an EXACT measurement
b) Be careful in attaching the beam scale to the ceiling beams of your robot lab
...
Goodness, YES. Please get a copy of the rules. It explains a lot, and if your robot does NOT follow the rules, you will not be allowed to compete. Really, it is very important. - DonRotolo [more] 
