[Lab] Arduino CapSense library + Shiftbrites + interference

[Andrew O'Malley]

Hi everyone,

I have a pretty specific situation here that I'd love to hear your thoughts on:

I have four panels of 5x6 Shiftbrite arrays, attached to plastic
supports.  In front of each panel I'm placing an acylic sheet for
diffusion, and on this sheet are several wires attached to an Arduino
running the CapSense library.

I can get useable data from the capsense arrangement running by
itself, but when placed (3") in front of the shiftbrite arrary, the
capsense values become extremely unstable (huge fluctuations making
the data unuseable) when the Shiftbrites are receiving data.  The
capsense circuit and the shiftbrite circuit are electrically isolated,
as the capsense circuit is running from its own battery while the
shiftbrite circuit is plugged in via a power supply; so I don't think
it's noise from the power supply.  Is it possible that the array of
Shiftbrites are giving off significant EMI while shifting data?

If this is the case, anyone have any suggestions for add-on shielding
for the shiftbrite array/cables?

Thanks for your time and attention!

Andrew