# Motor distance conversion (reply asap)

Can anybody here create a rough conversion chart for motors. Here’s what I would need help with: converting degrees (motor degrees) to inches and/or millimeters. Thanks for the help and support!

Hmm
That is a bit of a difficult question
Are you talking about converting the degrees to inches on a circles of varying sizes like(insert gerometry function i cant remember). Or are you trying to take degrees and translate that to how far a wheel attached to the motor will move when the motor turns by X degrees?
I hope i didnt just confuse you or myself by trying to unconfuse the question

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Probably the second one. Thanks!

so vexcode should have some sort of conversion factor based off of the size of wheel you choose on drivtrain setup. This can be calibrated and i am not code enough to do that tho

that’s ok! thanks for your help!

The way to calculate this from your motor rotation is:

motor rotation in revolutions * gear ratio * (wheel diameter * pi).

so if your motor turns 180 degrees, on a 1:2 gear ratio for speed that connects to a 4" wheel, the surface of the wheel would spin:

0.5 * 2 * (4 * pi) = 12.56, so the surface of your wheel would rotate 12.56 inches if your motor turns 180 degrees.

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thank you SO much! that’s really useful!

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Do you really need to calculate? If your using V5 you can just go to ‘devices’ and measure rotations and just push the robot as far as you want it to go and then just directly plug it into your code. That’s how I do my auton. Of course, you will still need lots of fine tuning either way.

Doing the calculation and understanding the calculation, in the long run, is a far better approach and can be applied quicker and easier than the approach you stated. It would allow you to set up your program with a function that you could call that could then apply to any movement at any point in your auton rather than having to “push” your robot for every segment of your auton path. MATH is a great thing.

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Don’t get me wrong, I love math, but if you do it that way, you still have to measure “every segment of your auton” and convert it on the code instead of just pushing. Yeah, you can have a function to convert, but (cough cough) you don’t need no function for good ol’ revs.

since the field is divided into 24" sections, it’s pretty easy to measure the points where your robot needs to travel in inches. and it’s a lot easier for people to read, because we have a good idea of what 24 inches is, but not a great idea of what 20 revolutions looks like, since it changes from bot to bot.

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