SEN50 / SEN54 / SEN55 I2C Address: 0x69

How to set the address

There is no address pin: the address is set at the factory, so it is always 0x69.

The SEL pin must be tied to GND for I²C.

Devices that use the same addresses

Two devices on the same bus can’t answer on the same address. These modules from our list also use 0x69:

Device	What it is	Shared address
BMI270	6-axis IMU	0x69
MPU-6050	6-axis accelerometer + gyroscope	0x69
MPU-6886	6-axis IMU	0x69
MPU-9250	9-axis IMU (accel + gyro + AK8963 magnetometer)	0x69
PCA9685	16-channel 12-bit PWM / servo driver	0x69

If two of them end up on the same address, move one with its address pin, put one behind a TCA9548A multiplexer (0x70–0x77), or use a second I²C bus: the ESP32, ESP32-S3 and RP2040 have two I²C controllers (the ESP32-C3 has one).

Check your whole bus →Add the SEN50 / SEN54 / SEN55 and your other modules: the checker finds conflicts, suggests free addresses and sizes the pull-ups.

7-bit and 8-bit address

I²C addresses are 7 bits long. Some datasheets and libraries write them as 8-bit numbers, with the read/write bit added on the right: that is why the same chip can appear as 0x69 or 0xD2. Arduino’s Wire library and ESPHome use the 7-bit form.

7-bit	Binary	8-bit write	8-bit read
0x69	1101001	0xD2	0xD3

Check that it answers

Upload this sketch with the SEN50 / SEN54 / SEN55 wired to SDA and SCL: it tries every address the chip can use and prints the one that answers. On an ESP32 the default pins are GPIO21 (SDA) and GPIO22 (SCL); on an Arduino Uno, A4 and A5.

#include <Wire.h>

const byte ADDRS[] = {0x69};

void setup() {
  Serial.begin(115200);
  Wire.begin();
  for (byte a : ADDRS) {
    Wire.beginTransmission(a);
    if (Wire.endTransmission() == 0) {
      Serial.print("SEN50 / SEN54 / SEN55 answers at 0x");
      if (a < 0x10) Serial.print('0');
      Serial.println(a, HEX);
      return;
    }
  }
  Serial.println("No answer: check the wiring");
}

void loop() {}

In ESPHome the bus is scanned at boot (scan: true is the default): the log lists every address that answers.

i2c:
  sda: GPIO21
  scl: GPIO22
  scan: true

Pull-up resistors

SDA and SCL need pull-up resistors to the supply. Many breakout boards already carry them, often 4.7 kΩ or 10 kΩ, and with several boards on the bus they add up in parallel. The I²C checker works out the allowed range for your bus voltage and speed.

Frequently asked questions

What is the I2C address of the SEN50 / SEN54 / SEN55?

0x69. It is fixed: there is no address pin.

Can I use more than one SEN50 / SEN54 / SEN55 on the same bus?

Not directly: the address is fixed, so two would clash. Put each one on a different channel of a TCA9548A multiplexer, or use a second I²C bus.

Why doesn’t the SEN50 / SEN54 / SEN55 show up in an I2C scan?

Check, in this order: SDA and SCL not swapped; ground shared between the boards; pull-up resistors on SDA and SCL; the module powered at the voltage it is made for; and that your code uses the 7-bit address (0x69), not the 8-bit one (0xD2).

Addresses checked against the SEN50 / SEN54 / SEN55 datasheet.

SEN50 / SEN54 / SEN55 I²C address