I know this might sound very basic, but I’m quite new to robotics and I’m trying to build a project robot with my father. I know what I need to get the motor turning, but my question is just how do I connect the wheels to the motor? I’ve heard you HAVE to you use a gearbox but others have said there are other ways than just that… Any help would be appreciated. Thanks in advance!
Can you post a picture of what motors you are using? It usually depends on the motor’s output (drive) shaft.
We can help you more if you tell us what motor and what wheel you want connected.
Generally motors run at speeds that are too fast for a wheel to do something useful (unless you want to shoot a ball or something) which is why a gearbox is often used.
Generally if you want to drive a wheel off a motor you would use a hub that matches the shaft on your motor and bolt it onto the wheel. But this depends on the motor and wheel combo, so more details are needed.
It depends on the motor and wheel that you want to match up, and what the purpose of the wheel is.
For example, in some cases you could press the wheel onto the axle of the motor. You could use a hub to do the same thing. But, in those cases you want the wheel to spin as fast as the motor does, and for the vast majority of motor/wheel setups that isn’t the case. So, you’ll need some sort of gear reduction. That could be a chain or belt setup with different sizes of sprockets or pulleys, respectively, or it could be a gearbox.
The big trick is that it’s entirely dependent on the motor, the wheel, and the application. What works well for, say, a shooter wheel might not work so great if you’re trying to use it in a drivetrain (read: might not work at all).
Alright, well I haven’t actually purchased any motors or wheels or anything of the sort just because I didn’t want to waste money on some parts then have them not go together…
I was thinking of using these wheels
http://www.andymark.com/product-p/am-2647_blk.htm?CartID=3
and using these motors
But again, I’m rather new and don’t know to what extent those will work together (if at all). So if these don’t go together, could you just suggest a cheap(ish) alternative to what I have chosen? Thanks again everybody!
Now, what did you say your application was again? We can’t tell you if that’s a good idea or not without knowing a little bit about what you’re trying. By the way, your free speed would be about 95 ft/**second **if my math is right and you’re driving with that thing (RPM of motor at 5500, C=pi4" diameter, and 1 revolution moves you 1C). Depending on loaded speed, you’ll stall pretty quickly, though. (Again, if you’re driving. If you’re trying to shoot something, you might need to go the other way and spin faster.)
Sorry! Some wheels will be for driving some for moving an arm-like body part.
If this is for a non-FRC project, then you don’t need to adhere to typical allowed motors.
Cost is obviously important for you, I would suggest looking at the gearboxes and motors sold by BaneBots, their gearboxes and motors are on sale at the moment, same with their wheels.
http://www.banebots.com/category/P60_7.html
The motors you select are dependent on the weight and size of your robot.
But a 550 or 775 motor should easily be fine, for a driving a decently sized robot
http://www.banebots.com/product/M5-RS550-12.html
http://www.banebots.com/product/M7-RS775-18.html
For wheels have a look at these http://www.banebots.com/category/COLSON_WHEELS.html and these
http://www.banebots.com/category/COLSON_HUBS.html
With a robots project, the motor controllers are going to be a big cost component and would probably be about $45 if you went for the low cost REV Spark
Way too fast. As I noted in my edit, your theoretical top speed is 95 ft/second on driving, and you really don’t want to know how hard you’ll hit with an arm in motion…
I think you need the JVN Calculator (might be a hair out of date, but it’ll have the CIM in there).
Yep the JVN calculator is what you want, it’ll help you work out what motors and what gearing to use to drive your robot and also the motor and gearing required to move the robot arm.
JVN released an updated calculator for 2016: http://www.chiefdelphi.com/media/papers/3188, but the most likely won’t make a difference for this purpose
Alright everybody I’ve figured it out with the gearboxes and motors.
For the drivetrain I’m going to use
http://www.andymark.com/Motor-p/am-0912.htm?CartID=8
this motor and
http://www.andymark.com/product-p/am-3105.htm?CartID=7
this gearbox.
For an “arm-like” function I’m going to use
http://www.andymark.com/Motor-p/am-0255.htm?CartID=10
this motor and
this gearbox.
Thanks for all the help!
I think you’ve got a scale issue. The 9015 motor is about the size of a prescription bottle, while the CIM is about the size of a Coke can. Neither was made with the Neverest gearboxes in mind, and I’d be shocked if a Neverest gearbox could withstand what a CIM puts out for any length of time. (We use 2-6 of those to drive 150-pound robots.)
What size of robot are you looking to build, either in dimensions or weight? What, if anything, does the arm have to lift? That will help us get you in the right direction. 
The whole robot is going to be about 3 feet tall and a foot and a half wide and long. The whole thing made of aluminum (idk how much that would weigh). And the arm would have to move nothing but itself. I will have 4 motors for the drivetrain and one for each arm.
If you upload a sketch of what you are looking to do we may be able to better help you
I don’t think you should spend money on motors until you’ve done the calculations for what you actually need.
Since you haven’t given any requirements, we can only help you find components that are compatible with each other.
You may want to consider starting smaller in case something doesn’t go the right way. Gearboxes especially can run hundreds of dollars even for just a drivetrain and arm. Smaller also lets you use hobby servos for rotation.
We will need more information to help you. To start what is this for? Are you part of a first team? What kind of “arm” are you talking about? How many degrees of freedom is the arm going to have? What does this arm need to do? How are you manufacturing this robot you mentioned aluminum but are you going to be using sheet metal, tubing, extrusion ect? What exactly is your budget for the entire project? Do you have a control system in mind? What surface will this robot be driving on?
I think you should brush up on some basic robotics knowledge before undertaking this project. If you continue your chances of success are a shot in the dark which is not at all what you want especially if you are on a tight budget.
This helps!
That’s more or less the size class of a FIRST Tech Challenge robot (their size limit is 18" cubed). That says to me that a NeveRest motor is probably the scale to be using for this. Not that you can’t use a CIM or other motors, but they’re probably going to be overkill.
I can’t say for certain without seeing the design, but I’d bet a few judiciously-used NeveRest motors and some 1/16" wall aluminum shapes (okay, maybe a little 1/8" in high-load areas) would get you pretty far.
I think if you have an FRC team near you, you should go visit them and see if they’ll let you just pick through their boxes and see what they’re willing to give you.
My team still has boxes of mismatched transmissions, Power Wheels transmissions and old motors that I’d never put on a competition robot, etc. If I knew a kid was going to actually use them, I’d be pleased to give them away.
The mentors and seasoned members can give you advice too. Way better in person than on CD.
Good Luck!