Arduino based Milliohm Meter with LCD display

Arduino based Milliohm Meter with LCD display

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One of the best things about being a maker is the ability to make your own tools. We have covered the development of several electronics tools in past, from voltmeters to battery testers. For today’s tutorial, we will add another tool to the list by examining the development of a Miliohm meter made by danielrp @ www.instructables.com

A milliohm meter is a device used in determining the resistance of small resistors, PCB traces, motor coils, inductance coils, and transformer coils, or calculate things like the length of wires. It provides a resolution, not built into regular multimeters, making it easy to get accurate readings in the milliohm range.

There are quite a number of Miliohmeter builds on the internet, but today’s tutorial will chronicle the efforts of instructable user Danielrp. Daniel’s version of the meter is based on a precision current sink and a high-resolution ADC controlled by an Arduino Nano. The current sink is based on the LT3092 precision current source/sink which, using a network of resistors and transistors is set to function as a sink. For the ADC, the high resolution, MCP3422A0 I2C ADC is used.  Just one of the channels of the ADC is used, and it is connected differentially to the Resistor under test “S+ S-“. The MCP3422 is configured as 18bit but as S+ is always going to be greater than S-, the effective resolution is 17bit.

To reduce the influence of the resistance of the test leads on the measurement, the devices use Kelvin connectors as leads to connect the resistor under test to the measurement point.

Arduino based Milliohm Meter with LCD display – [Link]

Mike is the founder and editor of Electronics-Lab.com, an electronics engineering community/news and project sharing platform. He studied Electronics and Physics and enjoys everything that has moving electrons and fun. His interests lying on solar cells, microcontrollers and switchmode power supplies. Feel free to reach him for feedback, random tips or just to say hello :-)

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