Racking my brain, why am I seeing these tiny voltage fluctuations?

Thread Starter


Joined Jan 20, 2013
So I hung a long wire off one of the unconnected A/D inputs, it's just as flat as before.

But the A/D input connected to the pressure sensor now has the unexplained rise/drop at a different time. It shifted with DST going away.

I guess isolated power supply is the last step now. Or an RF box around the pressure sensor. :)
Last edited:


Joined Apr 11, 2010
I am not surprised that you’re seeing those minor fluctuations. In whatever is reading the ADC, I implement a smoothing algorithm. So far, I use a rolling average of several readings. The length of your FIFO buffer depends on the responsiveness required by your application.