The INA219 breakout board can be powered by the 5V or 3V pin on your Arduino and communicates via I2C.
To wire up the STEMMA QT version:
- Connect board VIN (red wire) to Arduino 5V if you are running a 5V board Arduino (Mega, etc.). If your board is 3V, connect to that instead.
- Connect board GND (black wire) to Arduino GND
- Connect board SCL (yellow wire) to Arduino SCL
- Connect board SDA (blue wire) to Arduino SDA
- Connect Vin+ to the positive terminal of the power supply for the circuit under test
- Connect Vin- to the positive terminal or lead of the load
To wire up the original version:
Connect to the microcontroller
- 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.
