Potentiometers, ADC, and chatter

A

ADWSystems

Member

• Jul 14, 2015

• #1

To make a short story shorter. I have a potentiometer hooked connected from 5V to ground with the wiper connected to an ADC pin on an Arduino. I am getting some chatter in the readings which I would like to smooth. Am I best off averaging X readings from the ADC or could I place a cap to ground on the wiper to steady the input voltage?

 

ericgibbs

Well-Known Member

Most Helpful Member

• Jul 14, 2015

• #2

You could try a 10nF or 22nF.
Its possible your pot is noisy.
What is the value of the pot.?

 

A

ADWSystems

Member

• Jul 14, 2015

• #3

I think it is 10K now because that is what I had on hand. The final plan was to use 50K to minimize power consumption.

 

atferrari

Well-Known Member

Most Helpful Member

• Jul 14, 2015

• #4

Could you try a different one of the same value?

 

ericgibbs

Well-Known Member

Most Helpful Member

• Jul 14, 2015

• #5

ADWSystems said:

I think it is 10K now because that is what I had on hand. The final plan was to use 50K to minimize power consumption.

Click to expand...

The recommended maximum source impedance for a PIC's ADC is between 5k and 10k, depending upon PIC type

What is the signal you are planning to digitise.?

 

AnalogKid

Well-Known Member

Most Helpful Member

• Jul 14, 2015

• #6

The filter cap is the easiest thing to try quickly, but the filter corner frequency (and hence the filter's effectiveness) will change with the pot rotation. A software LPF will give more consistent performance, after you work out the program and verify that it works.

ak

 

A

ADWSystems

Member

• Jul 14, 2015

• #7

The signal is just the input from the wiper from a potentiometer hooked from 5V to ground. It's purpose is to act as a (cheap) retentive setpoint input.