Best gyro for frc.

[ayeckley]

Originally Posted by Jared

I don't think you'd need mu-metal to shield because it's a higher frequency magnetic field.

I intended to speak in very general terms only. I agree that mu-metal is of little benefit in the FRC context, but for different reasons than what you are referring to. Philso's approach (above) certainly offers the highest bang-to-buck ratio. The last time I had to buy mu-metal (~1994) I think the minimum order quantity was 1000 lb. It's also nearly the same density as lead.

Originally Posted by Jared

The motors brushes create lots of really high frequency em fields that can be blocked by copper.

Would there not also be a "low" frequency (<2 KHz-ish) magnetic field associated with the fundamental brush-pass frequency, in addition to the broad, higher-frequency spectrum you described? I'm being wishy-washy on the exact frequency because I don't recall the armature design of the CIM. I don't believe I've ever had one apart, personally.

Originally Posted by Jared

The best way to solve the interference problem is to twist the gyros signal and return cable. The two conductors act like a loop which pick up the magnetic field from your motors. Twisting these two conductors will decrease the effective loop area and greatly reduce the interference. You can prevent common mode interference with a grounded shield on the conductors.

Strongly agree. Also effective for E-field shielding.

Originally Posted by Jared

Increasing our switching frequency to 15khz makes interferences problems 15 times worse than the 1khz.

Not sure I agree there, but that's off-topic.