Hi -
Can someone please tell me what the purpose of the Vref pin is and when I should use it?
I’m been reading posts that say it is for the analog conversions but they don’t say when and how to use it.
I’m planning on having several analog inputs that are in the range of 0-15vDC that I will use a voltage divider to rescale between 0-5vDC. Do I need to do anything with the Vref pin?
Thanks,
Greg
Red Rider,
“Someone” certainly can. The first “someone” I suggest you consult is the Arduino Reference, specifically [here.
As to your particular situation, the answer (as is often the case in engineering) is “it depends”. You can put a similar (to the ones you’re going to use for the analog signals) voltage divider on whatever your signal sources use as their 15 V reference, and feed the resulting “5V” signal as Aref. That way the analog signals will be compared to something that tracks the 15 V reference and that will reduce the variability in measurement due to any differences in how the 15V and the Arduino’s 5 V vary. If both your 5 V and 15 V supplies are very steady and you can tolerate some variability, then it may not matter whether you connect Aref.
Have Fun,
Eric ](http://www.arduino.cc/en/Reference/AnalogReference?from=Reference.AREF)
Thanks Eric - I’m still finding my around the reference area.
Greg
Greg,
You’re welcome!
One picky point that could lead to substantial frustration: In the Arduino world, the thing we’ve been discussing is called “Aref”, not “Vref”. I presume the “A” comes from “analog”. It’s not that I had any trouble understanding “Vref”, but if you’re searching the Arduino site, you’ll do much better if you use their term.
Eric