Interference in the ADC

[johnerrington]

If you want reasonably reliable results you may find it useful to read this:

skillbank: Experiments and projects with an Arduino microcontroller

@roman_arduino

What could be wrong?

If your circuit has anything more than this

then other components may be introducing noise.

So the first step would be to disconnect everything except the supply and the voltage source.
And the next step would be to look at the voltage input AND the supply voltage with an oscilloscope. A DVM will not tell you if a voltage is stable.

Please provide the basics - a schematic, a photo and your code.

How to make a schematic you can post.

When you submit a question on the forum you will usually need to add a schematic (circuit diagram). The tutorial that follows will explain some ways to create a useful image; however lets start by explaining how to add the image to your post. Its easy. Having created the image all you need to do is : Save the image somewhere convenient - maybe your desktop Start your post, and place the cursor (insertion point) where you want the image to be shown; [upload image to forum] 3: click th…