MicroOhmMeter

Description

Design assumptions:
-RPI PICO with LCD ad controller
-usage of precise ADC (MCP3910) to measure voltage on DUT and precise resistor
-max +/-200mV on DUT
-kelvin clip connection
-DAC (MCP4822) controlled bidirectional current source (+/-3A)
-3x 18650 lipo for power supply
-as high resolution as possible from above configuration

Above analog part was simulated.... time to draw PCB and order the parts

Optional possibles/TODOs
-bulid-in BMS (charger and balancing)
-nice case
-find and order suitable parts

Discussions

Kuba Sunderland-Ober wrote 01/07/2024 at 21:42

Inspired by your project, I’ve made a first version of my own take on it: https://hackaday.io/project/191204-sdo-milliohm-meter-v1

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Kuba Sunderland-Ober wrote 05/29/2023 at 20:37

If you do the error budgeting you will find out that precision op-amps are not quite necessary for this project. Any modern-ish general purpose low voltage op-amp will work great. Even the lowly LM358 from late 1970s will work well as long as the ambient temperature doesn't vary too much.

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Piotr wrote 01/07/2024 at 18:53

Yes, you are right. I recently redesign everything. Plan is to finish it this year :)

Are you sure? yes | no

MicroOhmMeter

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