Arduino Battery Monitor
Is your battery going flat in your battery-powered Arduino ATMega328P project?
See https://www.youtube.com/ralphbacon video #160
(Direct link to video: https://youtu.be/C-VnvjEP0-k)
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Get a timely warning before your batteries go flat!
Battery-powered, Deep Sleep Arduino (ATMega328P) projects are great but how do you know when the batteries are nearly depleted?
In the last video #159 we explored a simple, battery-powered PIR project using an ATMega328P, as found in every Arduino UNO and Nano. Many times I was asked how I could detect the battery voltage and warn the user that it was time to replace the batteries.
In this video I show how we can do that with no extra components, all by the magic of the bandgap voltage set on the AREF pin, either internally or externally.
ATMEL decided not to precalibrate the AREF voltage (cheapskates!) so each chip has to calibrated first using a one line sketch. Easy stuff. And whilst reading the voltage might look a bit esoteric, you don't have to understand all the code - just use it as a function in your sketch or include a small library. All this right here in the GitHub!
List of all my videos
(Special thanks to Michael Kurt Vogel for compiling this)
http://bit.ly/VideoList-RalphBacon
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Same goes for here!
ATMega328P Data Sheet
https://www.sparkfun.com/datasheets/Components/SMD/ATMega328.pdf
What's a Bandgap Voltage Reference?
https://en.wikipedia.org/wiki/Bandgap_voltage_reference
Nick Gammon's page on ADC
http://www.gammon.com.au/adc
Arduino Forum on the same subject
https://forum.arduino.cc/index.php?topic=331178.msg2285210#msg2285210
Arduino's page on Reference Voltage (AREF)
https://www.arduino.cc/reference/en/language/functions/analog-io/analogreference/
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My channel and blog are here:
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https://ralphbacon.blog
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