ADC Crosstalk

Hi everyone,

I seem to be experiencing some crosstalk between adc data and some kind of counter, can anyone confirm this?


A/D crosstalk between analogue inputs is a well known fact.

A/D inputs need to be driven by a low impedance source (<10k),
or the input can be read twice (without delay), with only the second reading being used,
and/or a 10-100n cap from input to ground can be added.

Not sure what you mean with “some kind of counter”.

Hi Leo,

When I say counter, I am referring to a cyclical digital signal, possibly but not necessarily increasing in value over consecutive time samples in a single period.

Let's see if someone knows what I am saying better before we make any more replies.

Is this analogue pin connected to a source with low enough impedance, not just “floating”.
Is ground of that source not shared with any other ground.
Is the 5volt supply (default Aref) not dragged down by this digital signal, e.g. from a flashing LED.

If you want better answers, then you have to supply the diagram and the code.
Read the forum rules.

Let's see if someone knows what I am saying better before we make any more replies.

Let's see if you can do better than vague hand-waving before posting again.

can anyone confirm this?


If you want help, describe the problem clearly, post the code using code tags, and post a wiring diagram.

Hello Jremington and the rest,

If you would kindly hold your noise, we may be able to increase the chances of having someone more practiced than myself to reply.

For informed help, please read and follow the directions in the "How to use this forum" post.


I am receiving some kind of sensor noise, and I am having trouble fully filtering it. I've drawn a picture of what I believe the noise signal looks like, with the most problematic area circled:

I have tried libraries such as ResponsiveAnalogRead, but that library also fails in what I believe is the circled area. Is there a library that can filter this noise out?

Ciao, it looks like my post got moved to this thread!

A little more information about my application, I am wanting to use Arduino to control electric bike, both throttle and braking, but this kind of noise is a real problem! For throttle, it can make a surging torque, and even with responsive filter the sudden blip can cause an unwanted sudden torque and wheel slip. For braking, we might have unwanted brake activation, or filtered it might cause a wheel lock during braking!

Ciao, it looks like my post got moved to this thread!

Same person, same problem, n'est pas?


If you would disregard my cable modem for now, I would also use Arduino to control led brake lights and turn signals, and I also am concerned about false brake light activations