Tisham Dhar has made it easy for us to use the ATM90E26 electricity metering IC in our project. I have used both his Featherwing implementation and the DIN rail implementation. Currently, I am interested in the DIN rail implementation because this implementation will allow me to plug in his hw into a junction box (you know - the thing with all the circuit breakers typically in your garage....). While I personally believe Tisham's documentation could use improvement (after all - Tisham is an exceptional engineer - it is not easy to be exceptional in both engineering and documentation) I found Tisham's resources to be very useful:
This library abstracts the ATM90E26 meter on top of the SPI interface. It makes it easy from REPL or from a CircuitPython file (e.g.: main.py) to access the ATM90E26.
I have an "older" and "newer" library. The older library is HappyDay_atm90e26.py. This worked great with Tisham's Featherwing...
For my most recent project I am using HappyDay_M90E26_SPI.py. I was having challenges getting expected readings (e.g.: line_voltage was giving me 0 when I should have gotten something like 124). I made what I think of as minor cleanup to the init() method (mainly setting Checksum Two back to Tisham's original values). It worked so...YIPPEE!
No that I had a .py library, I needed to get it into .mpy format. .mpy format dramatically shrinks the file size prior to copying it within the lib subdirectory of the CircuitPython hw. For this I used the mpy cross executable. e.g.: $ ./mpy-cross HappyDay_M90E26_SPY.py from a terminal line.
The version of CircuitPython I am currently using is 3.1.2.
I used din_test.py to test. Here's some values I got:
sys_status = energy_sensor.sys_status
meter_status = energy_sensor.meter_status
line_voltage = energy_sensor.line_voltage
print('system status: 0x{:x} \nmeter status: 0x{:x}\nline voltage: {}'.format(sys_status,meter_status,line_voltage))
system status: 0x2
meter status: 0x800
line voltage: 240.13