What scale does your team use to weigh the robot? We’re trying to find one but the only ones in a good price range had a platform which is too small.
Thanks!
We use a scale with a small platform. It is a digital scale, so we set a piece of plywood on it then zero out the scale then weigh the robot. Works very well.
1 of my teams uses the shipping scale at the factory in which they work
the other team uses a bathroom scale with a modified platform on it so it can support the robot…
i would say for an inexpenive solution you can use a bathroom scale and then for the final meausrement take it to a shipping store UPS or FedEx and they can give you an accurate weight
I think the folks at PBR (our main sponsor last year) did the weighing. Then when we really had to figure it out fast, we just hauled it all over to the gym and weighed it on the scales that the athletic department has. Worked fine for us this year.
We also use the school’s gym scale. I figure if they can handle those 300 pound wrestlers they can handle our puny little 135 pound (hopefully less) bot. 
Wayne Doenges
ex-Team 535
Soon to be a Rookie again :eek:
Our team this year used two different scales. The main one we use at the high school’s woodshop is an old farm scale. It’s about 100 years old and I believe it’s original use was to weigh grain. This one has different weights you can add to it and the scale is mounted on wheels so you can roll it around. It’s made of cast iron (very heavy) with oak boards for the weighing platform and makes one heck of a noise when you roll it down the ceramic tile in the hall! :yikes: Just don’t try to sneak up on anybody with it. The second one we used was at one of our sponsors shops. We met there when the school was closed due to snow or the extreme cold we had back in January (how can anybody forget?! :rolleyes: ). This scale was a digital scale used in the shipping department. Both these scales worked quite well, and we even weighed ourselves. 
wow all these high tech and alarmingly low tech but still effective scales! for the past two years we’ve used a bathroom scale from a mentor’s house, and usually we try to find a balance point on the robot so we can weigh it without it touching the ground. failing that, we have someone hold the robot while standing on the scale and we weigh it that way. naturally this is just for a rough estimate and whenever we can we take it to be weighed, i believe we’ve used vet scales in the past before. course all the scales in the world wont help you if you’re 135lb two nights or a night before ship :ahh:
I would not recommend using a traditional needle bathroom scale. We have found ours to be up to 8 lbs (!) off depending on the surface the scale is sitting on and how you load the mass. If you must use a bathroom scale, be sure to calibrate it with water or lifting weights but even then I wouldn’t trust it to more than about +/- 2lbs.
we just guessed and the night before shipping we were finally able to borrow the wrestling team’s and found out we were quite overweight… which is why we ended up with many many holes
You can get a good digital scale from Office Max or Office depot. The scale has a range to 200 lbs or the KG equilv. All in 1/4 lb increments.
All ypou have to do is make a platform (plywood surface. If the plywood is in place when you turn the scale on it zeros out and you are ready to go.
Cost? It was about $35
Back when I was on 992, we would just drive the parts down to the local FedEx office, where they were more than happy to help us with our unusual request (they only asked that we come after 7pm, when they aren’t as busy).
If you want to buy a scale, I would recommend a scale with a wired remote. This will allow you to place a plywood platform over the top (you could even make up a nice wooden cover that fit the size of the scale if you wanted), and still be able to read the numbers.
The price of such a scale really depends on the accuracy you are looking for. Costco has a Digital Shipping Scale with wired remote for $50 that is good to 310 pounds, but the accuracy is (+/-1.0% + .22 lb), which translates to +1.52/-1.08 pounds for a 130 pound robot.
For a more accurace scale, such as this Health-O-Meter H349KL, which is accurate to ±.2%, or ±.26lbs @ 130 pounds, you will need to spend around $250.
Most high school gym scales can be tilted depending on the loading. The one at our school, we could drop 3 lbs at weigh-in by standing at the back of the scale. We could drop a lot more if we hung off, but that was suspicious looking to hang off the back of the scale… :rolleyes:
Wetzel
In 1998, we used a needle bathroom scale, and ended up needing to lose 30lbs when we weighed with a real scale at nationals.
We tried a digital scale we bought, and it was off by as much as 18 pounds, I believe.
we tried the scale the school uses for wrestlers, and it was off by 8 lbs.
We used a series of weights from the weightroom to test the accuracy of the scales.
The funny thing is the scales were never off by the same amount. It always got progressively worse as you added weight.
We found out we had to shave 30 lbs off our bot last year. It looked like swiss cheese when we were done
We used a vet hospital (for large animals) scale…it worked great and was within a pound of the competitions scale. I think a vet place is easy to find and usually have a scale big enough for a robot and a much better solution compared to a bathroom scale.
In 2002 we took the robot to the airport and used the luggage check-in scales, they’re pretty accurate and, if you have nothing better closer to you, it’s a very good option.
In 2003 we didn’t weight the robot - ended up adding ballast to increase traction, a robot builder’s dream 
This year we only had to take a pound off the robot, despite our somewhat “ghetto” weigh in techniques…
http://www.colegio-provincia.com.br/Dsc00699.jpg
http://www.colegio-provincia.com.br/Dsc00701.jpg
another answer :
Dont!
Wait until the competition then find out your massivly overweight (yes, we did that lol, had to remove our forklift mechanism…) …
proper planning etc…
Scales tend to be off by percentages rather then x amount, so that makes sense.
Wetzel
Heh, I think we must have the most ghetto way of weighing a robot…
We use a digital bathroom scale with someone carrying the robot while standing on the scale. Then we subtract the person’s weight and we have the robot’s weight. 
We use a digital scale that that measures up to the hundredth place in pounds. Really nice since the plate is about three feet by three feet.
I would not really rely on bathroom scales because of the very small weighing surface area. I would even recommend bringing your robot to Publix and have it weighed in their spiffy scale (accurate to half a pound).