Would anyone know where I could get small or not so bulky motors that are still powerful? It would also be nice if they weren’t too expensive.
http://www.robotmarketplace.com/products/motors_main.html
banebots.com
trossenrobotics.com
are all places to get motors.
how much power are you looking for? what is the application that these are going to be used in?
thanks, vivek
-Vivek
I prefer going to banebots and picking a motor with a gearbox, very strong and lightweight.
What is the application? The more you can tell us, the more we can help.
Then again we don’t know what your building…
A brushless Etek motor would be fun 
15 hp at 200 Amps and 24-36 Volts. That thing could kill you
Well basically… I’m building a robot! The robot is small and it requires a very low center of gravity. By doing this I need to place the motors and much of the electronics at the bottom of the bot. The problem is the motors we used for the 2008 competition were far too bulky to work out in THIS robot.
I just also realized I need to work out the battery as well… anyone know if it’s possible to get a smaller battery that’s practical for a competition?
How small is small, and what kind of competition are we talking? Is it robot sumo? What’s the maximum size for a robot? There are a plethora of options on the internet, but we need a little more definite information before we can help more. And if you don’t want to share, google is usually pretty good at giving you what you want.
But for some more sights try:
allelectronics.com (generally filled with random awesome parts)
solarbotics.com (they carry a bunch of excellent parts specifically for small robots)
Give us a lot more details about the competition. Size of robot? time periods? what it’s doing? etc…
In the end the battery choice will probably be based on the motors you’re running, how much current they are drawing, how long the matches are and how much the robot has to weigh.
I would look at RC shops, like towerhobbies.com, given that the robot is in that size-range. There are literally thousands of options for motors and batteries.
Lithium Polymer batteries have one of the highest energy densities. But they usually aren’t too good at dumping lots of current.
NiMH and NiCad rc-car battieries are better for high current, but will be larger and heavier.
I’m talking about a FIRST Robotics competition. I like experimenting rather than sticking to the “same old” in a season so I’m trying out different drive trains. As for the robot… thinking of how to describe it… well you know those egg shaped annoying baloon things you used to beat the crud out of as a little kid? You know the thing no matter how many times you hit them they just went right up? I’m basically building one of those that moves. It’s meant to be a robot that’s small+speedy and it can never be knocked over.
Cool Idea. If you want it to be able to be knocked around, but never flipped over, a low CG is good, but the way the upper structure works relative to the chassis is really what is important. For instance A sheet of plywood has an extremely low CG (when flat), but I can easily flip it over. The real trick to the Bop-a-clown is that the curvature of the inflatable makes it so the CG can never be above a tangential surface unless you flip it over perfectly balancing the weight on top.
If you took the Kitbot chassis and shortened it into a box (approx. 24x24"), strapped a trackball to the top of it, you would have a good initial prototype, and likely wouldn’t need any special motors or pancake batteries.
Low CG is right and make a 6 wheel drive but make sure the middle two wheels are square with the back and center wheels. Drop the center like this if you want:
http://www.chiefdelphi.com/forums/showthread.php?p=758988#post758988
and a 6 wheel drive is really good for power and pushing.
I agree with you. I was the driver of our team’s robot which had 6 wheel drive. The thing about this robot creating a 6 wheel robot wouldn’t fit the egg shaped. The purpose of the robot is to have a menuverable, small, speedy robot that’s near impossible to knock over. I was actually thinking of using a 2 wheel drive. The very low center of gravity should be enough to keep it stable.
If you don’t want a manipulator on it, maybe you want this:
with this:
Just make a robot that’s maximum frame height is slightly larger than the largest thing you need to fit inside it (presumably the battery), and use 6" wheels.
Then you can flip and your wheels will always touch the ground since they’re taller than the frame.
I’m actually pretty set on the design of the robot, but until I prototype it I won’t be able to see how practical it would be in a competition.