How to shield magnetic field


I’m using a compass with the robot and when the motors are running, they generate magnetic field around them, which affects the performance of the compass. Is there a way to shield the magnetic field generated by the motors using materials which I can find around the house? (Or any general easy solution)

Thank you.

I mounted my compass on top of a mast made of PVC pipe. It was far enough away from the robot body that I never saw any effect from the motors.

I guess you could encase the motors in something.

If you can get the small pre-cut steel pipes from home depot for like $2 each then tuck the motor into it and put paper wading to fill the open gaps and if there is enough room put an end cap on it.

I don’t know how this will affect the motor, it may hurt it or increase performance i don’t know.

The metal will focus the magnetic field inward and keep it from escaping.

I have used this when i built a gauss accelerator, when i put the pipe over the coil it shot slightly harder because the magnetic field was focused inward.

This will help lower the magnetic field.

Once the is complete you need to encase you compass in a pvc pipe which might stop the em field a bit.

Using a metal pipe to encase the compass may not work because the compass uses a magnet and it will be shielded.

You could also get a Faraday type material and put it all over the motors.

I have seen it on the Mythbusters, it stops cell phone signals and radios but i don’t know about em fields.

I don’t know much about magnets so if anything i said is incorrect feel free to tell me.

That will take a while - So it will wait until later :wink: Several things you said are almost correct…

Magnetic fields are not stopped by anything as far as I know. I think that they extend to infinity from their source. But… their strength falls off rapidly (with the cube of distance in free space).

To get the field strength to fall off even faster, you can surround the field source with something other than free space. There are special materials that are good for this.

Look for something called MuMetal (I forget how to spell it). It is an alloy that works better than plain old iron or steel. By helping to concentrate/guide much of the flux in a field, a MuMetal case does help lower the strength of that field outside of the case.

However, trying to use a magnetic compass on a metal Vex robot that uses electric motors and gives the compass a realtively rough ride, might simply be fighting a losing battle. Think hard about whether you can use either a different sensor or a different way to transport it.


Simple fix, just use the pneumatics.