Hey Guys,
I have a VEXplorer that I put together for my son’s 6th grade science olympiad.
The rules state that if you buy a commercial kit that it must have at least one ‘functional modification’ defined as the lack of it means that the robot will not work or will work differently. I am stumped, do you guys have any ideas or have been through this yourself. Any ideas welcome. Thanks
the first idea that comes to mind is that you could change the wheel setup on the bot.
you could add slightly smaller wheels to the front and back to help it turn easer.
http://www.vexrobotics.com/vex/products/accessories/motion/276-1496.html
or you could make it a tank tread driven bot.
http://www.vexrobotics.com/vex/products/accessories/motion/276-2168.html
(although I wouldn’t recommend this for slippery floors)
but I would use you imagination as well (what would make this bot even somewhat better)
You could have that the claw/arm turns with a turntable
Whatever you do, do not put 2.75" rubber wheels on the front of the bot to make it “turn [easier].” That isn’t going to help. The same goes for tank tread. That’s just going to slow you down. I’m going to suggest you get Omni Wheels for the base, if you wanted to improve your drive.
Looking at the game, you have to move legos, batteries, ping pong balls, a tennis ball and place them all in a jug. The claw that came in your VEXPlorer kit should be more than capable of doing that. Maybe buy some sensors, like a Potentiometer or a Limit Switch that you could use to prevent the motor closing your claw from burning out. You could also use the potentiometer to make arm presets, so instead of fiddling with the controls to score the driver can just push a button, drive over the jug and drop. I would also STRONGLY suggest you swap out the gear ratios in your base motors if your kit came with 393s. That will speed up your base by quite a lot.
That’s some really basic improvements. You could always make an entirely different arm/intake, but that’s going to require a few weeks of work. You could put the kit together in an hour or two, no problem. I’m not sure how much energy you want to put into this project.
I would agree that mixing wheels doesn’t work on foam but for hard surfaces I thought it might help. people to this all the time for inline roller hockey and it is also done in frc (at least the kit bot in a day) since the Vexplorer is a six wheel drive, outfitting it with Omnies would coast $50 so I just passed right over that idea.
Ya, tank tread would be pointless, except that the Vexplorer is a two motor drive so the idea was to increase the torque.
Alright my turn;)
the Vexplorer uses completely different electronics from the EDR line.
the brain is non-programmable and vex sensors and motors don’t work with it.
I personally loved the gear ratio best about the Vexplorer and it would be the last thing I’d change.
One of things that I did when I had a Vexplorer was to move the lift tower back and forth to figure out how I liked it best. you could also make it so the arm doesn’t dig into the ground when you lower it to far.
you could also angle the claw down like this:
__
^
but that would make it hard to see the claw from the point of view of the camera (not that the camera can’t be moved)
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I should say that although my first vex kit was a Vexplorer, I never competed in the science Olympiad. (though I did do math Olympiad)
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First year away from SO. But what does the rule say about starting the robot. Often it needs to be turned on with a pencil. An inline on/off would be possible if that is the case. Another could be wiring motors together or even replacing the VEX battery pack with a within S/O LIMITS better battery. There is I think also one non-motor port on the VEXplorer(either to power camera or light) and you might be able to add a unique function like powering a ducted fan to aid a task. I don’t know the tasks either but adding a passive latch made from lexan or maybe a custom ratchet again using lexan. Both ideas are from here on the forum, Latch (toss up) ; ratchet (sack attack). Also if using the claw, try substantially modifying it. It’s grasp can be broadened with stand-offs across the length of its arms significantly improving its capacity or its tips can have be modified to increase dexterity–several years ago, there was a task to pick up a dime in robot ramble and using thin cutouts from a window blind allowed us to pick it up. Or you can even build a better claw out of Vex parts (or even Wood) much like those used in Round UP. Again, not knowing the tasks but throwing out ideas–how about adding the Vex Turntable–I know the VEXplorer motors will not fit but you might be able to rig a 269 to the VExplorer though without a motor controller you might risk burning something out.
Okay, I just realized another poster listed the tasks–even without the requirement for a functional modification, picking up batteries (I assume D Cell in S/O) you will be better off if you add elastics to assist the motors in lifting for one. If challenged, your son can explain the physics. The specs on the motors are somewhere and the in/lbs for the weight on the end of the arm is improved immensely. Also the vex claw can be modified to assist in picking up the ping pong balls and Tennis balls (and maybe legos) by adding half a plastic golf ball to function as a cup with which to secure the balls, add it to both sides and the legos are easier as well as the thin sides going around eliminates the precision needed to manipulate the claw pincers on two flat surfaces. If you have room a half a wiffle ball or plastic baseball might be optimal for even the battery/maybe one of each wiffle/golf?