2Tricky:
retrolefty:
The first thing I would try as a simple experiment would be to remove the external Aref voltage you are applying to the Aref pin and use the instead default internal Avcc reference and see if your wobble improves, gets worst, or remains the same.Lefty
Lefty, Aref was only tried after suffering with wobble and made very little perceivable difference compared with the Unos' default 5V. I should just check: When you say 'internal', do you mean something other than using the 'DEFAULT' Const when setting the reference in 'analogReference()'...this is how it was being used prior to using the Aref pin (although it was used by default, i.e. no specific call to 'analogReference()')...
Thanks Lefty
No, I meant the DEFAULT mode with no analogReference command issued.
I worked with lots of ADC and DAC stuff in a oil refinery before retirement, so have some experience with trying to make quality analog voltage conversions in the real world. My opinion of the AVR 10 bit ADC is that it is very handy for hobby type projects and applications but falls pretty short of being a instrumentation quality measurement device. In todays world there are so many really nice and affordable external ADC chips and modules available and many are easy to interface to an arduino via SPI or I2C. So if accuracy, resolution, repeatability, common noise cancellation via differential inputs are important to your application I would suggest you look into external ADC converters.
Lefty