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Old 01-03-2011, 08:29 AM   #1 (permalink)
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Join Date: Feb 2009
Location: Estonia
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Green frog - '97 Audi A4 Avant 1.9TDI 81kW
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new feature idea: battery voltage

has this idea been discussed before? At least I haven't seen it.
Anyway, I would like to see battery voltage in MPGuino and started searching how to measure 12V battery voltage (max should be 15V I think) and found this link and some other voltage divider pages.

I am going to build it, probably It even does not need extra input to mpguino - I am going to measure 12V input voltage before voltage regulator. Voltage regulator signal would be used as Vref
extra parts needed: 2 resistors and some wire :P
I am choosing resistors to make divide-by-three divider, so signal to atmega input is 0-5V
What ohms should I choose? 10K and more I think?

Also I am going to add coolant temperature to this screen (needs extra input pin) along with liters/hour and RPM
new screen will be "Car sensors" or similar.


Last edited by meelis11; 01-03-2011 at 03:39 PM..
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