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Bevels
10-11-2009, 02:58 PM
I am getting electrical interference from other electronics in the area where my SSC32 needs to function. Where can I find a good box for shielding the controller. Ideally it should have two holes for serial ports and a hole for the power to run through.

Adrenalynn
10-11-2009, 03:12 PM
How did you determine that the SSC32 was suffering from EMI? Outside of radiation that would be damaging to humans, I wouldn't expect the ATMEGA168 to be that susceptible to EMI... After all, flash memory was originally designed for the space program where they need to worry about things like cosmic radiation and quantum uncertainty...

Are you sure it's not the wires running to and from that are being EMI'd?

Bevels
10-11-2009, 04:02 PM
my first one was experiencing erratic behavior and we discovered that the problem was some motors nearby. We put the SSC32 in a box and shielded the cables and the problem stopped. The problem is that we have 2 SSC32s and only have 1 box and no one knows where it came from so now I need to get another one.

Adrenalynn
10-11-2009, 06:39 PM
Have you tried a ferrite core on the wires? (a "Choke")

Or putting filter caps on the motors? Or both?

jes1510
10-11-2009, 10:35 PM
I'll second Adrenalynn here. .1uF caps across the motors. Run the motors from a separate power supply if possible. Twisting the motor wires will help as well. Finally keep all motor wires as short as possible and away from electronics.

I would guess that you aren't generating much EMI, rather you are dipping the power supply with a big in-rush current when the motors start.

Bevels
10-11-2009, 11:26 PM
I'll second Adrenalynn here. .1uF caps across the motors. Run the motors from a separate power supply if possible. Twisting the motor wires will help as well. Finally keep all motor wires as short as possible and away from electronics.

I would guess that you aren't generating much EMI, rather you are dipping the power supply with a big in-rush current when the motors start.

The motors causing the interference are run from a separate power supply. It cannot be just a big rush in current causing it because then the erratic behavior of the servos would not continue as the current settles. However, the problem persists as long as the motors are active. It is a shielding problem. Are there any good boxes that would do the trick?

jes1510
10-11-2009, 11:49 PM
Anything made out of aluminum will work. A plastic box lined with aluminum or copper foil will work too. Of course make sure that the thing is grounded or you can end up with the opposite effect.

lnxfergy
10-12-2009, 12:01 AM
my first one was experiencing erratic behavior and we discovered that the problem was some motors nearby. We put the SSC32 in a box and shielded the cables and the problem stopped. The problem is that we have 2 SSC32s and only have 1 box and no one knows where it came from so now I need to get another one. (Highlighted for emphasis)

Did you shield the cables on the second SSC32? Cables would be much more prone to picking up EMI than the traces on a PCB, so I'm thinking it's the shielding of the cables, not the box, that stopped the problem. Jes's suggestion about twisting the motor cables can also cut down the EMF generated.

-Fergs