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Compass module shielding

camerart

Active Member
Hi,
I'm using an AK8963C compass chip on a breakout board.

I'm getting errors, that possibly could be caused by inteference, and I want to know if shielding is normally used, and can a Compass chip be used inside a Faraday cage?
Cheers,
Camerart
 

Ian Rogers

User Extraordinaire
Forum Supporter
Most Helpful Member
I'm getting errors, that possibly could be caused by inteference, and I want to know if shielding is normally used, and can a Compass chip be used inside a Faraday cage?
Not really.... Anything metal within 150mm affects the reading... If it were permanent, you could calibrate it in..
 

Externet

Active Member
What metal would your Faraday cage be made of ? Copper, aluminium, iron, ... ?
 

camerart

Active Member
Not really.... Anything metal within 150mm affects the reading... If it were permanent, you could calibrate it in..
Hi I and E,
These modules are 1.6x1.6mm on a 10x25mm PCB. I was thinking about insulating them, then sticking copper tape over them, and grounding it to the bottom GND of the PCB.

I used to 'do' a demonstration in an electric museum, where a round magnet was dropped down a tube of plastic, and it dropped straight through. Then drop the same magnet down a copper tube and it took much longer to arrive.

If I 'did' the tape thing, then calibrate it, would it then be protected from electrical interference and capacitance (the signal changes when a hand is near)?
C.
 
Last edited:

camerart

Active Member
Hi,
As a matter of interest 'hopefully'

If a copper disc is spun within a magnetic field, then this will generate a voltage.

The reverse is also true: If an AC current is is used with an electro magnet, then the disc will spin, as in electric meters.

I had a gramophone with this type of motor, now in the Wantage museum.
C
 

rjenkinsgb

Well-Known Member
Most Helpful Member
The reverse is also true: If an AC current is is used with an electro magnet, then the disc will spin, as in electric meters.
Only if it has a shading band or coil on the pole piece, to add a rotational element. They are called "shaded pole motors".

Back to the original question - a non-ferrous screen around the compass element should reduce electrical interference from other things without affecting the compass itself.

Copper or aluminium foil or fine mesh should work.
 

camerart

Active Member
Only if it has a shading band or coil on the pole piece, to add a rotational element. They are called "shaded pole motors".

Back to the original question - a non-ferrous screen around the compass element should reduce electrical interference from other things without affecting the compass itself.

Copper or aluminium foil or fine mesh should work.
Hi R,
Thanks for the clarity, I'll add a cage if needed.
C.
 

gary350

Well-Known Member
I use a compass to aim my TV antenna in the correct direction according to TVFool. A cheep $1 compass causes me less trouble than a expensive compass. The expensive compass picks up metal so easy I need to be 20 ft away from all metal to get a good reading. $1 compass works fine 8 ft from metal antenna. If your compass chip sensitivity can be reduced it might work better.
 

camerart

Active Member
I use a compass to aim my TV antenna in the correct direction according to TVFool. A cheep $1 compass causes me less trouble than a expensive compass. The expensive compass picks up metal so easy I need to be 20 ft away from all metal to get a good reading. $1 compass works fine 8 ft from metal antenna. If your compass chip sensitivity can be reduced it might work better.
Hi G,
I'll check the settings.

It has a calibration routine, that should correct for stationary ferrous items.
C
 

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