You can filter the A/D input in firmware.  I use a combination of=20
averaging, and an IIR filter for this, and the amount of filtering=20
depends on how quickly I expect the input to change.  Since you're using=20
a pot (assuming that's the final intent and would not be replaced by=20
some fast sensor), then you can do quite a bit of filtering.

Effectively, think of it as looking at the change between the last A/D=20
value used and the current A/D sampled value, but only moving a small=20
percentage of that (towards the currently sampled A/D value, but only=20
partly there).  A significant difference that persists for several A/D=20
samples will move the output gradually towards that value, but a=20
transient difference will only change the output a negligible amount.

Cheers,
-Neil.



On 11/26/2015 3:26 AM, Jim Ruxton wrote:
> I am using a pot and the high resolution mode of an A/D on the 16f1828 .
> I am directly controlling a 10 bit PWM with the result of the 10 bit A/D
> input. I have a problem in that I want to avoid the noise of the A/D
> input from affecting my output. This happens if my pot is set just
> between two levels so the output fluctuates between two levels. Not very
> much only 1 or 2 levels out of the 1024 but this is significant in my
> application. I really only want the output to change if I physically
> move the pot. Currently I have fixed it by only outputting to the PWM on
> the output if the input changes by more than 2, assuming if it does I am
> moving the pot. This works in that my output is steady however it
> effectively lowers my resolution as well since the output now steps only
> when the pot moves more than 2 values. I was wondering if I should set
> up a timer interrupt for say 1 second and  if the output changes by more
> than 2  during that second assume the pot is being moved and allow level
> increments of 1. If it didn't move by more than 2 during that second
> assume the pot isn't being moved and lock the output. Am I on the right
> track here or can anyone recommend another technique .
> Jim
>
>

--=20
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