Sensirion SEN55 environmental node with ESP32

Supply 5 V Bus I2C I2C address 0x69 Measures particulates, voc, nox, temperature, humidity

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
VDD	Power	VIN	Pin 1. Needs 5 V for the fan: use VIN
GND	Ground	GND	Pin 2
SDA	I2C data (SDA)	D21	Pin 3. Add a pull-up to 3.3 V
SCL	I2C clock (SCL)	D22	Pin 4. Add a pull-up to 3.3 V
SEL	Not wired to the ESP32	—	Pin 5. Connect to GND for I2C
NC	Not wired to the ESP32	—	Pin 6. Not connected

Suggested wiring for the 30-pin ESP32 DevKit, avoiding flash, input-only and strapping pins. BoardPilot checks it for you as you wire.

This module is sold for 5 V. Its outputs may be 5 V: use a level shifter or a voltage divider on ESP32 inputs.

Starter code (Arduino)

#include <Wire.h>

void setup() {
  Serial.begin(115200);
  Wire.begin(21, 22);  // SDA = GPIO 21, SCL = GPIO 22
  Wire.beginTransmission(0x69);
  bool found = Wire.endTransmission() == 0;
  Serial.println(found ? "Sensirion SEN55 environmental node found at 0x69" : "Not found: check power, GND and SDA/SCL");
}

void loop() {}

Sources

Sensirion SEN5x datasheet, Pin 1 VDD 5 V, 2 GND, 3 SDA, 4 SCL, 5 SEL, 6 NC; I2C address 0x69, 100 kHz
Sensirion SEN5x datasheet, I2C lines are 3.3 V level; VOC and NOx are index values, not ppm

Try it in 3D in BoardPilot

BoardPilot Part data (JSON)

Part data: CC BY 4.0, free to reuse with credit to BoardPilot.

Sensirion SEN55 environmental node with ESP32

Pins and ESP32 wiring

Starter code (Arduino)

Sources

Try it in 3D in BoardPilot

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