adc instability with zetex 1022 current sensor

Hello all.

When I use the arduino's adc to measure voltage out of a zetex 1022 current sensor, my readings vary wildly (a range of about 200).

My multimeter on the pin reads a stable 3.6v

If I connect the adc input to a potentiometer instead, the reading is stable.

Any ideas why I'm getting such fluctuations?
Thanks,

Matthew

Probably a lack of decoupling:-

http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html

Thanks Mike. I read the link and I'm trying some decoupling out now.