INA219

Connects over

I²C

Address

0x40 (or 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F)

Made by

Texas Instruments

Datasheet

ti.com

Use it

hardware {
    device ina219: INA219
}

every 1s {
    let value: float = ina219.voltage()
    log("ina219", "voltage={value}")
}

On its own, the declaration puts the INA219 on the first I²C bus (SDA 21, SCL 22 on the ESP32) at 0x40. To choose the pins or the address, declare the bus and attach the device: device ina219: INA219 on i2c0 at 0x41 with i2c i2c0(sda: 21, scl: 22).

Methods

• ina219.voltage() -> float

  Bus voltage in V

• ina219.current() -> float

  Current in A

• ina219.power() -> float

  Power in W

• ina219.shunt_voltage() -> float

  Shunt voltage in V

Wiring

Specifications

Voltage

3V – 5.5V (logic); measures bus 0–26V

Current

1 mA active, 6 μA sleep

Current range

Default ±3.2 A through a 0.1 Ω shunt; ±400 mA via gain change

Resolution

12-bit (≈ 100 μA per LSB at default gain)

Interface speed

I²C up to 3.4 MHz

Tips

• Default shunt is 0.1 Ω — change if your load is < 100 mA (use bigger shunt for resolution) or > 3.2 A (use smaller).
• Measures HIGH-side current — Vin+/Vin- are at supply potential, not ground.
• Power calculation register saves you from manually multiplying V × I.

Alternatives worth knowing:

• INA226: Better accuracy + alert pin; 0–36V range.
• INA3221: 3-channel version — useful for measuring multiple rails.