Turns your Raspberry PI into 3-channel voltage and current monitor for other devices. This HAT contains three INA219 chips connected to I2C bus and measuring current on three independent channels. Shunt resistor may be selected per each channel according to desired purpose of HAT and expected working conditions.

Features

• 3 separate channels, each with own INA219 chip and shunt resistor
• Different possible power sources (controlled by jumpers):
• external (separate input for each channel), provided on screw terminal,
• internal 5V from common DC input
• may be shorted to Raspberry's 5V pin using solderjumper on the bottom or left as separate circuit,
• internal 3.3V - powered from 5V using internal LDO regulator
• Fuse and an "ideal diode" circuit protecting DC source when shorted.
• 4 LEDs:
• PWR (connected to 5V bus)
• 3 LEDs, one for each channel, connected to selected channel's power source
• Header for UART - to communicate with measured device
• Test points for I2C
• Standard ID EEPROM from hat specification

Devices

INA219 addresses:

• 0x40 Channel 1
• 0x41 Channel 2
• 0x42 Channel 3

Software examples

https://github.com/rafw87/hardware-modules/tree/master/modules/power-monitor-hat/applications

Example device

Channel 1 is set to external input (red jumper on External) provided from 9V battery and connected to the first LED.

Channel 2 is set to internal 5V input (red jumper on Internal, yellow on 5V) provided from Raspberry's 5V pin and connected to the second LED.

Channel 3 is set to internal 3.3V input (red jumper on Internal, yellow on 3.3V) provided from internal regulator and connected to the third LED.

All 3 LEDs are limited with 1kΩ resistors.

There is common ground so only one ground wire was required for all LEDs (here connected to channel 3).

Example screenshot from provided `power-monitor-plot` application.