Some Basic Questions...

[bglass]

I started a FIRST team a few years ago for my High School, and go put into a programming position. Unfortunately, I did not get to learn near as much about the constructing of our robot as I would have liked. I am now working on a research project, and this lack of knowledge has caused me to hit a few roadblocks. I'm hoping somebody in this community can help me (as you always have been able to).

I have a Control System (OI, Controller, and Radio Modems), and have built some Motor Controllers. I would like this robot to last, but also have financial constraints due to the nature of the project. What motors are the best to use for the price, and what parts do I need in order to connect wheels to them (and for that matter what wheels should I use). Beyond that, all I really need to know about is power. Do I need to use the fuse box as we used to? If I don't (or I guess if I do as well), what parts do I need to use to get my controller, motors, and other parts power?

Sorry if these questions are basic, but as I mentioned, I only have experience on the programming aspect of robotics. I appreciate your help.

[John Gutmann]

Well for me I made the frame of my robot out of 1/2" sqaure tubing with 1/16.

For motors on my frirst robot I used 3/8" drill motors and transmissions. I used a 3/8" bore sprocket onto the drill motor shaft and secured it with a steel roll pin. I used skyway 6" caster wheels. and the sprockets and hubs from IFI. with a PBASIC control system. I used the old Buss fuse panel. I just went to home depot to buy battery connectors, wire, crimpers, and terminal connectors. That was for my first robot though.

my current robot isn't done yet, so I will list prices for the first bot.

tubing - 1.15 per foot - about 16 feet total
motor/trannies - free from team
batteries 2x for 50$ from ebay they were froma certified dealer and brand new
wheels 4x at 5$ each. If you say your on a FIRST team skyway should give you the discount
hubs- 2 sets of 2 for 46$ totalI only used half a set for each wheel.
sprockets for wheels - 2x @ 20$ each
sprockets for tranny - 2x @ 12$ each
victor 883, buss panel, PBASIC system, radios - free from team

All in all I guess I got lucky with getting smoe things from my team. But if you buying eveything yourself. You could get a vex kit and use the tx, rx and RC to drive 2 victors. Look around for cheap 883s that no one uses any more. if you wanna go easy on motors and wheels, go online and look for fisher price wheels, inserts, motors and trannies. ALl you need to do is mount them on a 1/2" (maybe its a 3/8") shaft and stop the motor from spinning. that is easy, no chain , no sprockets, the whole drive in on little package. for the frame if you want a nice frame I would say go for the 1/2" x 1/2" x 1/16" in wall tubing. I welded it with the schools tig and my own 110$ chicago electric gasless mig and haveny had any problems. Never once broken a weld.

Anything else just IM me on aim: sparksandtabs

I am hoping to throw together a white paper someday to talke about people building their own inexpensive robots, or a robot that is a little bit more advanced.

-John

[Devo1098]

depending on how much you have, a basic robot can be very simple. i had access to a old kit bot frame and kop trannys, took me almost 1 hour to totally hook it up, i didn't use a frc control system because i don't have one, the entire bot cost me zero, but its just a basic kit bot, everything was supplied in the kit of parts.

now im in to dewalt motors, try eBay, for like 20 you can snag a working motor and transmission, you'll still need to use a lathe to make a part to use the shaft, but its cheap and easy.

welding a chassis in really nice, and custom. but not entirely vital, depending on how big the robot is, you might get away with 2x4's arranged in a box, with bearings mounted to the wood, i used 2x6's and some plastic helical gearboxes from the kit a while ago, and it really turned out nice,(well as good as wood gets) it had pneumatic wheels and was extremely simple and adaptable.

http://i162.photobucket.com/albums/t...8/DSC05492.jpg

Good luck with getting something rolling!

[John Gutmann]

Ohh thats a nice hot bot. Where did you get the helical gearboxes from? I would love to get some free kit tranies. I just bought some 56mm to use with CIMs.

-John

[Devo1098]

Originally Posted by John Gutmann

Ohh thats a nice hot bot. Where did you get the helical gearboxes from? I would love to get some free kit tranies. I just bought some 56mm to use with CIMs.

-John

Those 90 degree 2:1 gear boxes i got from the team, gears and all. I think they were in the kit 5 or so years ago, but in not sure because i was not part of the team. i have them now because no one wanted them, i really like them, their nice.

also because how the gear box is made you can switch it from 1:2 to 2 : 1 reduction, its nice having different ratios, only problem you have to tear the whole transmission apart to switch it. at least it better than chain.(thats my favorite part of that bot, NO chain)


Devo

[DonRotolo]

Originally Posted by bglass

What motors are the best to use for the price, and what parts do I need in order to connect wheels to them (and for that matter what wheels should I use).

As for motors, it depends on what you can find. If you come across 2 (or whatever number you want) motors (of any kind) see if you can use them - if not, find some others.

Bigger (or heavier) motors tend to be more powerful. Power equals force times speed. So, if you need speed but not force (or force but not speed) a smaller motor might be fine. Bigger also means more expensive as a rule.

Wheels are also what you can find. How to turn them also depends on what you have handy.

For example, you can use a car window lifter motor to drive wheelbarrow tires, with a gear or chain or belt or something. If you have window lifter motors and wheelbarrow tires. If you don't, then maybe tricycle tires, or wagon tires (think little red wagon), or whatever you can scrounge.

Ever hear of dumpster diving? Is there a nght when everyone in town can throw out their non-garbage junk (like old chairs and stuff)? Find your robot parts, not only is it cheap, it sparks creativity by forcing you to figure it out.

Just get the big motors and gearboxes so common in FIRST out of your head, these are great for 120 lb FIRST-bots but ain't necessarily the best or only way to go.

Don