The INA219 breakout board can be powered by the 5v pin on your Arduino and communicates via I2C.

Connect to the microprocessor

  • Connect GND to GND
  • Connect VCC to 5v
  • Then connect SDA to SDA (Analog pin 4 on pre-R3 Arduinos)
  • And connect SCL to SCL (Analog pin 5 on pre-R3 Arduinos)
On R3 and later Arduinos, you can connect to the new dedicated SDA & SCL pins next to the AREF pin.  On pre-R3 Megas, SDA & SCL are on pins 20 & 21.

Next we must insert the INA219 current sensor into the circuit we want to measure:
Be careful inserting noisy loads that can cause a sharp current draw, such as DC motors, since they can cause problems on the power lines and may cause the INA219 to reset, etc. When using a DC motor or a similar device, be sure to include a large capacitor to decouple the motor from the power supply and use a snubber diode to protect against inductive spikes.

Connect to the circuit

  • Connect V+ to the positive terminal of the power supply for the circuit under test.
  • Connect V- to the positive terminal or lead of the load.  This puts the sense resistor in-line with the circuit.
  • Finally, connect a wire from the negative terminal of the power supply to GND.  This allows the sensor to measure the load voltage as well as the load current.
The photo below shows an INA219 breakout board configured to measure the motor supply current on an Adafruit Motor Shield.
Last updated on May 04, 2015 Published on Oct 26, 2012