INA219 with ESP32

Specifications

Power and logic levels

3.3 V: safe to connect directly

ESP32 pins, including those on a display board's connectors, work at 3.3 V and are not 5 V tolerant. Modules differ, so if in doubt, measure the signal before you connect it.

Wiring

Arduino code

#include <Wire.h>

const int SDA_PIN = 8, SCL_PIN = 9;   // use your board's I2C pins
const uint8_t INA219_ADDR = 0x40;
const float SHUNT_OHM = 0.1;          // check your module

int16_t readReg(uint8_t reg) {
  Wire.beginTransmission(INA219_ADDR);
  Wire.write(reg);
  Wire.endTransmission();
  Wire.requestFrom(INA219_ADDR, (uint8_t)2);
  return (Wire.read() << 8) | Wire.read();
}

void setup() {
  Serial.begin(115200);
  Wire.begin(SDA_PIN, SCL_PIN);
}

void loop() {
  float shuntmV = readReg(0x01) * 0.01;                 // 10 uV per bit
  float busV    = ((uint16_t)readReg(0x02) >> 3) * 0.004; // 4 mV per bit
  float currentA = shuntmV / 1000.0 / SHUNT_OHM;
  Serial.printf("%.2f V  %.3f A  %.2f W\n", busV, currentA, busV * currentA);
  delay(1000);
}

No extra library needed. Compiled for ESP32-S3 with arduino-esp32 3.x. Not yet tested by us on a physical sensor. Change the pins to match your board.

On a display

Read the value in your sketch and pass it to a label, or send it over MQTT and show it with an MQTT value in the editor.

Boards with a ready connector

Only boards whose connectors we have surveyed. Others may still work on free GPIOs.

Good to know

• Connect the grounds of both circuits.
• Do not exceed 26 V on the measured line.
• The shunt value sets the current scale. Check your module.
• Check the current rating of the module's shunt and terminals for your load.

What it is good for

• Battery monitors
• Solar charge displays
• Power supply dashboards

FAQ

Sources

• https://www.ti.com/product/INA219

Related parts

• BH1750
• SCD40