On Jun 3, 2006, at 6:21 PM, Zik Saleeba wrote:
> 60 feet of CAT5 is going to pick up quite a lot of power line hum.
> That's may be the low frequency noise you're seeing. You may want to
> re-think how you transport your signals. Personally I'd put a
> microcontroller at each sensor end and try to send the signal using a
> more rugged scheme such as CAN.

Yes, that might be what we have to do...

> Are you using any power supply filter capacitors near the sensors?

I put 10uF caps on each sensor as the Acroname manual mentioned.   
Didn't seem to help.

> That'd be a start. I'm not sure what the resistance of 60 feet of CAT5
> is but it's probably more than you'd like. The result of this will be
> that the sensors will communicate dirty power to each other more than
> they would on a shorter wire.
> If you have an oscilloscope have a look
> at the power at the sensor end. If it's full of spikes and flops
> around a lot add some filter capacitors at each sensor and/or try
> supplying each of the sensors from different conductors on the CAT5.

Other than the noise that the Sharp parts seem to be inducing  
themselves, the power looks fine at the end.  Those 1ms space dips  
the only thing I see.

thanks for the ideas!

darren
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