How to Use Gravity: H2S Sensor (Calibrated) - I2C & UART: Examples, Pinouts, and Specs

The Gravity: H2S Sensor (Calibrated) - I2C & UART (Manufacturer Part ID: SEN0467) is a high-precision sensor designed by DFRobot to detect hydrogen sulfide (H2S) gas concentrations in the environment. This sensor is pre-calibrated, ensuring accurate and reliable measurements right out of the box. It supports both I2C and UART communication protocols, making it versatile and easy to integrate into a wide range of applications.

• Industrial safety monitoring
• Environmental air quality detection
• Gas leak detection systems
• Laboratory experiments and research
• Smart home and IoT applications

Below are the key technical details of the Gravity: H2S Sensor:

The sensor has a 4-pin Gravity interface for easy connection. The pinout is as follows:

1. Power the Sensor: Connect the VCC pin to a 3.3V or 5V power source and the GND pin to ground.
2. Choose Communication Protocol:
   • For I2C: Connect the SDA and SCL pins to the corresponding I2C pins on your microcontroller.
   • For UART: Connect the RX pin to the TX pin of your microcontroller and the TX pin to the RX pin of your microcontroller.
3. Install Required Libraries: If using an Arduino, install the DFRobot H2S Sensor library from the Arduino Library Manager.
4. Write Code: Use the provided library functions to initialize the sensor, read data, and process the H2S concentration values.

• Avoid Exposure to Extreme Conditions: Prolonged exposure to high humidity or temperatures outside the operating range may damage the sensor.
• Calibrated Sensor: The sensor is pre-calibrated; avoid manual calibration unless necessary.
• Power Supply Stability: Ensure a stable power supply to avoid measurement inaccuracies.
• Communication Protocol Selection: Use I2C for multi-device setups or UART for simpler, direct communication.

#include <Wire.h>
#include "DFRobot_H2S.h"

// Create an H2S sensor object using the default I2C address (0x74)
DFRobot_H2S h2sSensor;

void setup() {
  Serial.begin(9600); // Initialize serial communication for debugging
  Wire.begin();       // Initialize I2C communication

  // Initialize the H2S sensor
  if (!h2sSensor.begin()) {
    Serial.println("H2S Sensor initialization failed!");
    while (1); // Halt execution if initialization fails
  }
  Serial.println("H2S Sensor initialized successfully.");
}

void loop() {
  // Read H2S concentration in ppm
  float h2sConcentration = h2sSensor.readH2SConcentration();

  // Check if the reading is valid
  if (h2sConcentration >= 0) {
    Serial.print("H2S Concentration: ");
    Serial.print(h2sConcentration);
    Serial.println(" ppm");
  } else {
    Serial.println("Error reading H2S concentration.");
  }

  delay(1000); // Wait 1 second before the next reading
}

1. Sensor Not Responding:

   • Cause: Incorrect wiring or power supply issues.
   • Solution: Double-check the connections and ensure the power supply is within the specified range (3.3V - 5.5V).

2. Inaccurate Readings:

   • Cause: Environmental interference or unstable power supply.
   • Solution: Ensure the sensor is used in a stable environment and the power supply is noise-free.

3. I2C Address Conflict:

   • Cause: Another device on the I2C bus is using the same address (0x74).
   • Solution: Change the I2C address of the conflicting device or use UART instead.

4. Library Not Found:

   • Cause: Required library is not installed.
   • Solution: Install the DFRobot H2S Sensor library from the Arduino Library Manager.

Q1: Can the sensor detect gases other than H2S?
A1: No, the sensor is specifically calibrated for hydrogen sulfide (H2S) detection and may not provide accurate readings for other gases.

Q2: How often should I recalibrate the sensor?
A2: The sensor is factory-calibrated and does not require frequent recalibration. However, if you notice significant drift in readings, contact DFRobot for support.

Q3: Can I use this sensor with a Raspberry Pi?
A3: Yes, the sensor supports I2C and UART, which are compatible with Raspberry Pi. Use appropriate libraries for integration.

Q4: What is the maximum cable length for I2C communication?
A4: For reliable communication, keep the I2C cable length under 1 meter. For longer distances, consider using UART.