Changing Project Direction to Use INA219 Power Monitor

I’ve had fun playing with MicroPython on an ESP8266, having an exception handling framework was especially welcome. I had originally intended to continue playing with MicroPython, gradually increasing the project complexity at each step, but I’ve changed my plan. The catalyst of this decision was a little breakout board for the Texas Instruments INA219 chip which measures electrical voltage (up to 26V DC), current (variable range depending on shunt resistor used), plus a built-in calculator for power (in Watts) from those two values. I bought mine off Amazon but I’ve since learned it was a knockoff of this Adafruit product so I’ll link to the original.

I had sat down with reference materials in front of me: the INA219 datasheet and the MicroPython I2C library. Then I felt a familiar sensation: that of my attention and enthusiasm fading. I know this sensation well! It stalled many projects in the past, and it is a warning sign I need to change directions fast or this project will stall as well.

I realized I was not enthusiastic about writing a MicroPython library for INA219 from scratch. There is educational value in doing so for sure, but for whatever reason right now I don’t feel the motivation I needed to reinvent this particular wheel. I went online looking for an existing solution and found a MicroPython Forum thread from someone who has done this work, pointing to their GitHub repository for the library.

Side note: Reading documentation for running this library on an ESP8266, I learned something interesting: the ESP8266 may encounter problems translating large MicroPython projects into executable code. The workaround is to use the MicroPython cross-compiler mpy-cross on my desktop and copy the resulting bytecode for execution on board the ESP8266.

If I could get this library up and running, I could see how to report resulting values to MQTT. Then I could perform calculations in Node-RED, and log calculated results into InfluxDB. Then I could start writing the infrastructure to read this data and make decisions on what to do in response. This is going to be a respectably large project and I don’t feel enthusiasm to do that, either! Apparently I’m not in the mood to learn by reinventing wheels, so I started looking to see what others have already done.

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