HDC1080 temperature + humidity (CJMCU-1080) with ESP32

Supply 3.3 V Bus I2C I2C address 0x40 Measures temperature, humidity

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
VCC	Power	3V3	Chip accepts 2.7 to 5.5 V. Use 3V3 so the on-board pull-ups stay at 3.3 V
GND	Ground	GND
SCL	I2C clock (SCL)	D22
SDA	I2C data (SDA)	D21

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

Check it is the real chip

Read register 0xFF: a genuine part answers 0x10. BoardPilot does this automatically in “Debug a problem”.

Starter code (Arduino)

#include <Wire.h>

void setup() {
  Serial.begin(115200);
  Wire.begin(21, 22);  // SDA = GPIO 21, SCL = GPIO 22
  Wire.beginTransmission(0x40);
  bool found = Wire.endTransmission() == 0;
  Serial.println(found ? "HDC1080 temperature + humidity (CJMCU-1080) found at 0x40" : "Not found: check power, GND and SDA/SCL");
}

void loop() {}

Sources

TI HDC1080 datasheet, I2C address 0x40 (fixed)
TI HDC1080 datasheet, Register map: 0xFF Device ID = 0x1050 (first byte read is 0x10)
TI HDC1080 datasheet, Supply 2.7 to 5.5 V

Try it in 3D in BoardPilot

BoardPilot Part data (JSON)

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