How to Use Duinotech Wi-Fi Mini DHT11 Temperature and Humidity Sensor Shield: Examples, Pinouts, and Specs

The Duinotech Wi-Fi Mini DHT11 Temperature and Humidity Sensor Shield (XC3856) is a compact and versatile module designed for IoT applications. It integrates the reliable DHT11 sensor for measuring temperature and humidity, along with built-in Wi-Fi capabilities for seamless wireless data transmission. This shield is ideal for projects requiring environmental monitoring and remote data access, such as smart home systems, weather stations, and industrial automation.

• Smart home automation (e.g., HVAC control, environmental monitoring)
• Weather stations and climate monitoring
• IoT-based data logging and remote sensing
• Educational projects and prototyping

1. Power the Shield: Connect the VCC pin to a 3.3V or 5V power source and the GND pin to ground.
2. Connect UART Pins:
   • Connect the TX pin of the shield to the RX pin of your microcontroller (e.g., Arduino UNO).
   • Connect the RX pin of the shield to the TX pin of your microcontroller.
3. DHT11 Data Pin: The DHT_OUT pin provides temperature and humidity data. This pin is internally connected to the shield's microcontroller, so you can access the data via UART communication.
4. Wi-Fi Configuration: Use AT commands or a compatible library to configure the Wi-Fi module for your network.

• Ensure the operating voltage is within the specified range (3.3V to 5V) to avoid damage.
• Place the shield in a location with good airflow for accurate temperature and humidity readings.
• Avoid exposing the DHT11 sensor to water or high humidity levels beyond its specified range.
• Use a level shifter if connecting to a 3.3V microcontroller to ensure proper UART communication.

Below is an example code to read temperature and humidity data from the shield and send it over Wi-Fi:

#include <SoftwareSerial.h>

// Define software serial pins for communication with the shield
SoftwareSerial wifiSerial(2, 3); // RX, TX

void setup() {
  Serial.begin(9600); // Initialize Serial Monitor
  wifiSerial.begin(9600); // Initialize communication with the shield

  // Send a basic AT command to check Wi-Fi module response
  wifiSerial.println("AT");
  delay(1000);

  // Configure the Wi-Fi module (replace with your SSID and password)
  wifiSerial.println("AT+CWJAP=\"YourSSID\",\"YourPassword\"");
  delay(5000);

  Serial.println("Wi-Fi setup complete.");
}

void loop() {
  // Request temperature and humidity data from the shield
  wifiSerial.println("GET_TEMP_HUMIDITY");
  delay(1000);

  // Read and display the response
  while (wifiSerial.available()) {
    String data = wifiSerial.readString();
    Serial.println("Sensor Data: " + data);
  }

  delay(5000); // Wait before the next reading
}

• Replace "YourSSID" and "YourPassword" with your Wi-Fi credentials.
• Ensure the shield's firmware supports the GET_TEMP_HUMIDITY command or modify the code accordingly.

1. No Response from the Shield

   • Cause: Incorrect UART connections or baud rate mismatch.
   • Solution: Verify the TX and RX connections and ensure the baud rate matches the shield's default (9600 bps).

2. Inaccurate Temperature or Humidity Readings

   • Cause: Poor airflow or sensor exposure to extreme conditions.
   • Solution: Place the shield in a well-ventilated area and avoid exceeding the sensor's operating range.

3. Wi-Fi Connection Fails

   • Cause: Incorrect SSID/password or weak signal strength.
   • Solution: Double-check the credentials and ensure the shield is within range of the Wi-Fi router.

4. Data Transmission Delays

   • Cause: Network congestion or high latency.
   • Solution: Test the shield on a less congested network or reduce the data transmission frequency.

Q1: Can I use this shield with a 3.3V microcontroller?
A1: Yes, the shield supports 3.3V operation. However, ensure proper UART voltage levels using a level shifter if needed.

Q2: How do I update the firmware of the Wi-Fi module?
A2: Refer to the manufacturer's documentation for firmware update instructions. Typically, this involves using a USB-to-UART adapter and a firmware flashing tool.

Q3: Can I use this shield without Wi-Fi?
A3: Yes, you can use the DHT11 sensor functionality without configuring the Wi-Fi module.

Q4: What is the maximum range of the Wi-Fi module?
A4: The Wi-Fi module supports a range of up to 30 meters indoors, depending on environmental factors.

This concludes the documentation for the Duinotech Wi-Fi Mini DHT11 Temperature and Humidity Sensor Shield (XC3856).