Robo-Cross B

[binary010101]

i mean what can i hold up the arm with?

While you're manipulating objects, or while it's in rest position?

[robotman]

Today i was talking to the person on my team doing robo-cross and he already built the robot and has it working [sorta]. Anyway I have a few questions about it. He said that he wont be able to use a remote control for it and he was thinking of either a. programming it to run the course b. use a sound sensor or c. use a motion sensor [for example take a meter stick and put it in front of the robot and guide the meter stick where you want the robot to go.] My question is are any of these illegal? I dont have the rules with me and even if i did, i dont get robot stuff. Also, is there a limit to the amount of motors you can use? Right now we have 3. 2 on the wheels and 1 on the claws. He wants to put another on the claw so he can make the claw go up and down but he doesnt know if that's legal.

ok the meterstick idea i think could be classified as illegal but u can have as many motors an you want as long combined battery voltage doesnt exceed9.6 volts

[computernerd4826]

yeah we had so many motors last year that we used 2 separate vex microcontrollers

[binary010101]

Today i was talking to the person on my team doing robo-cross and he already built the robot and has it working [sorta]. Anyway I have a few questions about it. He said that he wont be able to use a remote control for it and he was thinking of either a. programming it to run the course b. use a sound sensor or c. use a motion sensor [for example take a meter stick and put it in front of the robot and guide the meter stick where you want the robot to go.] My question is are any of these illegal? I dont have the rules with me and even if i did, i dont get robot stuff. Also, is there a limit to the amount of motors you can use? Right now we have 3. 2 on the wheels and 1 on the claws. He wants to put another on the claw so he can make the claw go up and down but he doesnt know if that's legal.

ok the meterstick idea i think could be classified as illegal but u can have as many motors an you want as long combined battery voltage doesnt exceed9.6 volts

That means you can use up to 6 standard D or C cells.

[Pleiades]

oh ok i get it. so it has nothing to do with motors then?

[cooltiger]

Nope, anyway our team got lucky and is going to order our robot of e-bay but if your team wants a vex, better get it soon

[captbilly]

Is there a limit to the number of batteries that you can use this year. Last year there was only a maximum voltage limit, not a limit on the number of batteries. We used two 7.2 volt batteries plus a 4.8 volt battery on our Nationals robo and made a special point to tell the event coordinator that there were this many batteries (and that they were not in series so no circuit got more than 7.2 volts.) and were not DQed.

I also want to throw out my oppinion of the VEX stuff. Electronically it may be OK for what you want to do but mechanically it seems pretty junky to me. We used VEX for our regional and state competition and did pretty well, but it was definitely not reliable enough for Nationals use. I can't even count the number of gears we stripped and motors we broke with the VEX. I like to use a motor or sevo that will not break even when stalled, and the VEX stuff definitely cannot be counted on to hold up to anything like a stalled condition (unless you severely limit the current to the motors). In addition the tolerances on the bearings, motors, gears etc. are pretty coarse and there is lots of play in the parts. I don't doubt that a reasonable robot could be built with VEX but I would be curious about how many top 10-20 teams used VEX at Nationals.

[robotman]

most of the vex motors i use dont stripp i only have one motor that i have had to change in the two years of competition

[computernerd4826]

Is there a limit to the number of batteries that you can use this year. Last year there was only a maximum voltage limit, not a limit on the number of batteries. We used two 7.2 volt batteries plus a 4.8 volt battery on our Nationals robo and made a special point to tell the event coordinator that there were this many batteries (and that they were not in series so no circuit got more than 7.2 volts.) and were not DQed.

I also want to throw out my oppinion of the VEX stuff. Electronically it may be OK for what you want to do but mechanically it seems pretty junky to me. We used VEX for our regional and state competition and did pretty well, but it was definitely not reliable enough for Nationals use. I can't even count the number of gears we stripped and motors we broke with the VEX. I like to use a motor or sevo that will not break even when stalled, and the VEX stuff definitely cannot be counted on to hold up to anything like a stalled condition (unless you severely limit the current to the motors). In addition the tolerances on the bearings, motors, gears etc. are pretty coarse and there is lots of play in the parts. I don't doubt that a reasonable robot could be built with VEX but I would be curious about how many top 10-20 teams used VEX at Nationals.

vex did just fine for us, and we won nats.......
we used clutches on the motors, and all year we only stripped one clutch.
also, the only problems with gears were a few teeth breaking of now and then, because we had an insane gear ratio with a lot of gears (it was slow, but strong) and even then it only happened when we lifted the scoop while going into zone d because the weight bounced around and put more force on it. in about 300 runs, we broke 5 12-tooth gears.....
in my opinion, vex is one of the strongest kits that you can buy

[robotman]

i agree that its strong