Add: Ina219 current/voltage sensor over I2C

[Suke0811]

• Hardware to be tested, at least it seems to be alive so far

[Suke0811]

Q:
any idea why this is the case?
edg/parts/Ina219.py:29: error: Argument 1 to "init_from" of "Port" has incompatible type "DigitalBidir"; expected "DigitalSink" [arg-type]
When i locally run mypy, i got the same error but otherwise, i don't see the error.

[ducky64]

Mostly looks good, few fixes inline.
Let's get it tested before merging?

[Suke0811]

The sensor seems to be alive and the voltage is reasonable.

I used https://github.com/RobTillaart/INA219 instead of the adafruit library since they assume a predefined shunt resistor and no mechanisms to change it without modifying the library.

[ducky64]

hooray!

[ducky64]

Actually, would it make sense to specify the default shunt resistance t 0.1ohm for compatibility with the Adafruit board?

edit - I guess 2mOhm is what is in the TI reference datasheet, though 0.1ohm might be a good default for things that don't process serious power. idk 🤷‍♀️, either's fine I guess, feel free to merge as-is.

[Suke0811]

Adafruit lib has hardcoded calibration with a set shunt resistor, so maybe it's not good for general purposes. In the inline comment, they say implement your own lol

  void setCalibration_32V_2A();
  void setCalibration_32V_1A();
  void setCalibration_16V_400mA();

  // By default we use a pretty huge range for the input voltage,
// which probably isn't the most appropriate choice for system
// that don't use a lot of power.  But all of the calculations
// are shown below if you want to change the settings.  You will
// also need to change any relevant register settings, such as
// setting the VBUS_MAX to 16V instead of 32V, etc.

[ducky64]

Fair enough! 2mOhm it is, and the datasheet is probably a more authoritative source anyways.