SparkFun Forums

[Sawakaki]

I am planning on building a custom RC tank based on the Scorpion form the Halo video games. To keep to the original, I am planning on using 4 motors (1 for each tread pod) and controlling them using the Arduino. My problem is I have no idea how to figure out how much torque the motors will need to move the tank. I plan on using 12v DC gearmotors, either from a cordless drill or simply purchased online. My design will be rather large, roughly 2 1/2 ft long, and I am estimating the weight at around 15 Lbs including batteries. I'm looking for power over speed i.e. I want it to act like a tank that can climb over just about anything. Also, if I strip the motors from a drill, does the battery chemistry in the model have to be the same as the battery chemistry of the drill from which the motors were taken? Any help or suggestions would be greatly appreciated, thanks.

[waltr]

Go to the SoR web site, Robot Tutorials and check out the motor calculator. This will give you the required torque.

[Sawakaki]

That's an amazing site, thanks! If I'm understanding that calculator correctly, it's only giving the requirements for a single motor that's moving the whole robot. If I plan on having 4 motors, I just divide the RMF by 4 to get what I need per motor?

EDIT: I wasn't paying attention to the calculator when I asked that question, sorry about that.

Thanks a bunch for the help!

[waltr]

OK

[trueRF]

Cool project! I'd like to see how it turns out. Check out hobbyking and Polulu for cheap motors. Getting the raw motors from one of those sites would probably be cheaper than buying 4 drills and tearing them apart.

Motors aren't dependent on the battery chemistry. It's all electricity to them. Just make sure that you can supply enough voltage and current to get them to spin.

Hobby king has a huge selection of high performance batteries. Just check out the C rating and subtract 25% to get the actual, they tend to overrate their batteries.