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Measure current consumption #28

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Andreasdahlberg opened this issue Sep 6, 2014 · 1 comment
Open

Measure current consumption #28

Andreasdahlberg opened this issue Sep 6, 2014 · 1 comment
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@Andreasdahlberg
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enhancement node unit pcb

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@Andreasdahlberg
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It would be nice to measure the current consumption to better predict when charging is needed. This will also detect when the batteries needs to be replaced.

It can be solved by measuring the voltage drop over a shunt resistor, see picture below.
shunt
The current can then be calculated: A = Vdrop / Rshunt

The voltage drop is approximate 15 uV with the predicted current consumption. Since the processor has an 10-bit ADV we only have a resolution of 3.2 mV. (Vref / 1024). So its impossible to measure the voltage drop without some sort of amplification.
@Andreasdahlberg Andreasdahlberg self-assigned this Sep 6, 2014
@Andreasdahlberg Andreasdahlberg changed the title Measure current consumptio Measure current consumption Sep 6, 2014
@Andreasdahlberg
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The best solution would be to use a dedicated battery gauge IC.

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