I'm just looking for some advice with regards to reading analog voltages when my project is powered by a 3v coin cell.
Essentially I'm trying out my own wireless moisture sensor but have a nagging thought in my head about... If my arduino pro mini 3.3v has a default vref of 3.3v will my analogRead() values be effected as the 3v battery drains (overtime) ?
I'm guessing I would need to either:
Wire up the AREF pin - so as the battery looses voltage the VREF will fall with it. or Set up a voltage divider and use the 1.1V Internal reference.
I'm I on the right train of thought?
I appreciate your help! - and sorry if this post seams rushed... I'm supposed to be working :)