This is a small program that lets you use your raspberry pi and an ina219 module to monitor voltage, current, and mAhs realtime as well as create a log file.
You can skip this if your hardware is already working
First you need to have a raspberry pi and ina219 modules. You can buy both at adafruit as well as many other vendors. You will need to wire it up, enable i2c on your raspberry pi and test out the connections work.
| Raspberry Pi | INA 219 Module |
|---|
Pin 1 (3.3V) | VCC
Pin 6 (GND) | GND
Pin 4 (SCL) | SCL
Pin 3 (SDA) | SDA
VIN+ and VIN- on the module connect to the high side of your load. You can connect either via the header or the 2 pin screw terminal. Adafruit has an excellent tutorial.
 |
|---|
| Example setup with test load |
Once you have wired it up it's a good idea to test it. Again Adafruit has an excellent tutorial here on how to install and use i2cdetect to make sure you setup is correct. If it's working correctly you should see something like this
sudo i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: 40 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
You will need to install the pi-ina219 python library as well as urwid.
sudo pip install pi-ina219
And then the urwid python library
sudo pip install urwid
python ina219_monitor.py
There are a few constants in the code you might want to change depending upon your application.
- UPDATE_INTERVAL Screen refreshes in seconds. Defaults to 10 hz (0.1)
- LOGGING_INTERVAL Interval at which logs are written in second. Defaults to once a minute (60)
- SHUNT_OHMS Hardware configuration of your current sense resistor on your board. Defaults to 0.1 ohms
- LOGFILE name of the logfile, defaults to "logfile.log"
- MAX_EXPECTED_AMPS Maximum current expected in Amperes. Used by pi_ina219 to configure hardware. Defaults to 500mA (0.5)