EnviroDIY / EnviroDIY_Mayfly_Logger

hardware design files, example code sketches, and documentation for Arduino-framework EnviroDIY Mayfly data logger
https://envirodiy.org/mayfly/
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Vbat A6 electrically noisy #36

Open neilh10 opened 2 years ago

neilh10 commented 2 years ago

Measuring the LiPo battery voltage is through a resistor divider 10M / 2.7M with a capacitor 100nF Using this reference there is a lot of noise on the ADC.

Can the resistance's be changed to 1M / 270K for better noise immunity.

With 12.7M - the current drain 4.0V/12.7M = 0.31uA With 1.27M - the current drain 4.0V/1.27M = 3.1uA - negligble in the overall power management For an algorithm that detects the lowest battery voltage as an estimate for battery capacity, a windowed filter of 4 readings was implemented. The "Some Sw filtering" below used the lowest value read in the 4 to achieve some noise reduction

220321_swfiltering_8daysNoise