How to use CJMCU2080 HDC2080

The HDC2080 is a low-power digital humidity and temperature sensor from Texas Instruments. On a CJMCU2080 breakout board, it is one of the easiest ways to add accurate environmental readings to an ESP32 project — greenhouse monitoring, room comfort checks, or a simple data logger. In this guide we wire the module to an ESP32, install the HDC2080-Arduino library by lime-labs, and stream live readings to the Serial Monitor at 1 Hz, with optional high/low temperature and humidity alerts.

Components for This Project

What Is the HDC2080?

The HDC2080 measures:

10x40

HDC2080 vs DHT11/DHT22: I2C sensors like the HDC2080 are often more stable and faster than one-wire DHT sensors, and they share the bus with other I2C devices (OLED, RTC, etc.) on the same two data pins.

What You Will Need

Wiring — CJMCU2080 to ESP32

The HDC2080 uses I2C. On most ESP32 DEVKIT boards, the default I2C pins are:

Power: Use 3.3V on the ESP32. Do not connect VCC to 5V unless your specific module datasheet says it is 5 V tolerant — most CJMCU2080 boards expect 3.3 V. Keep wires short and tidy. If readings are noisy, add a 100 nF capacitor between VCC and GND near the sensor module.

Install the Arduino Library

This project uses the community library from lime-labs (fork of the original TI/tinkeringtech HDC2080 code, with fixes for newer ESP32 Arduino cores): GitHub: github.com/lime-labs/HDC2080-Arduino

Option A — Install from ZIP (easiest)

1. Open the repo → Code → Download ZIP
2. In Arduino IDE: Sketch → Include Library → Add .ZIP Library…
3. Select the downloaded ZIP file
4. Restart Arduino IDE if prompted

Option B — Manual install

1. Extract the ZIP folder and rename it to
   textcode

   1HDC2080

   if needed
2. Copy it into your Arduino libraries folder:
   • Windows:
     textcode

     1Documents\Arduino\libraries\

   • Mac:
     textcode

     1~/Documents/Arduino/libraries/

3. Restart Arduino IDE You should see File → Examples → Custom Libraries → HDC2080 (or similar) after a successful install.

Arduino IDE Setup for ESP32

If you have not set up ESP32 before, see our ESP32 getting started guide — summary:

1. Add board URL in File → Preferences
2. Install esp32 by Espressif Systems in Boards Manager
3. Select DOIT ESP32 DEVKIT V1 (or your board)
4. Set Serial Monitor to 115200 baud

The Sketch

Create a new sketch and paste the code below. It:

• Initializes the sensor at I2C address
  textcode

  10x40

• Resets and configures a comfort zone (temp 22–36 °C, humidity 40–55 %)
• Sets 14-bit resolution and 1 Hz measurement rate
• Prints temperature and humidity every second
• Checks interrupt status flags for threshold breaches

cppcode
1#include <HDC2080.h>
2#define ADDR 0x40
3HDC2080 sensor(ADDR);
4void setup() {
5  Serial.begin(115200);
6  while (!Serial);   // Remove this line if upload hangs on ESP32 without USB serial
7  // Initialize I2C communication
8  sensor.begin();
9  // Begin with a device reset
10  sensor.reset();
11  // Set up the comfort zone
12  sensor.setHighTemp(36);         // High temperature of 36°C
13  sensor.setLowTemp(22);          // Low temperature of 22°C
14  sensor.setHighHumidity(55);     // High humidity of 55%
15  sensor.setLowHumidity(40);      // Low humidity of 40%
16  // Configure measurements
17  sensor.setMeasurementMode(TEMP_AND_HUMID);
18  sensor.setRate(ONE_HZ);
19  sensor.setTempRes(FOURTEEN_BIT);
20  sensor.setHumidRes(FOURTEEN_BIT);
21  // Begin measuring
22  sensor.triggerMeasurement();
23}
24void loop() {
25  Serial.print("Temperature (C): ");
26  Serial.print(sensor.readTemp());
27  Serial.print("\t\tHumidity (%): ");
28  Serial.println(sensor.readHumidity());
29  uint8_t status = sensor.readInterruptStatus();
30  if (status & 0x40) {
31    Serial.println("High Temperature threshold breached!");
32  }
33  if (status & 0x20) {
34    Serial.println("Low Temperature threshold breached!");
35  }
36  if (status & 0x10) {
37    Serial.println("High Humidity threshold breached!");
38  }
39  if (status & 0x08) {
40    Serial.println("Low Humidity threshold breached!");
41  }
42  delay(1000);
43}