How to Use WiFi Transceiver: Examples, Pinouts, and Specs

The REYAX RYLR998 is a high-performance WiFi transceiver module designed to enable wireless communication by transmitting and receiving data over WiFi networks. This compact and versatile device allows devices to connect to the internet or communicate with each other seamlessly. It is widely used in IoT applications, smart home devices, industrial automation, and wireless sensor networks.

• Internet of Things (IoT) devices
• Smart home automation systems
• Wireless data logging and monitoring
• Industrial control systems
• Remote device communication

The RYLR998 module has a total of 8 pins. Below is the pinout and description:

1. Power Supply: Connect the VCC pin to a 3.3V regulated power source and the GND pin to ground.
2. UART Communication: Connect the TXD pin of the module to the RX pin of your microcontroller (e.g., Arduino UNO) and the RXD pin of the module to the TX pin of the microcontroller.
3. Enable the Module: Pull the EN pin HIGH to activate the module.
4. Reset the Module: Optionally, connect the RST pin to a GPIO pin of your microcontroller for manual or software-controlled resets.
5. GPIO Pins: Use GPIO0 and GPIO1 for additional control or input/output functionality as needed.

• Ensure the power supply is stable and within the specified voltage range (3.3V).
• Use level shifters if interfacing with a 5V microcontroller to avoid damaging the module.
• Place decoupling capacitors (e.g., 0.1µF) near the VCC pin to reduce noise.
• Avoid placing the module near sources of electromagnetic interference (EMI) to maintain signal integrity.

Below is an example of how to connect the RYLR998 to an Arduino UNO and send data over WiFi.

• RYLR998 VCC → 3.3V on Arduino
• RYLR998 GND → GND on Arduino
• RYLR998 TXD → Pin 10 on Arduino (SoftwareSerial RX)
• RYLR998 RXD → Pin 11 on Arduino (SoftwareSerial TX)
• RYLR998 EN → 3.3V
• RYLR998 RST → Digital Pin 9 on Arduino

#include <SoftwareSerial.h>

// Define SoftwareSerial pins for RYLR998
SoftwareSerial wifiModule(10, 11); // RX = Pin 10, TX = Pin 11

void setup() {
  // Initialize serial communication
  Serial.begin(9600); // For debugging via Serial Monitor
  wifiModule.begin(9600); // Communication with RYLR998

  // Reset the module
  pinMode(9, OUTPUT); // RST pin connected to Digital Pin 9
  digitalWrite(9, LOW); // Pull RST pin LOW to reset
  delay(100); // Wait for reset
  digitalWrite(9, HIGH); // Release reset

  // Send initialization command to the module
  wifiModule.println("AT+RST"); // Reset command
  delay(2000); // Wait for the module to restart

  // Connect to WiFi network
  wifiModule.println("AT+CWJAP=\"YourSSID\",\"YourPassword\""); 
  delay(5000); // Wait for connection to establish
}

void loop() {
  // Send data over WiFi
  wifiModule.println("AT+CIPSEND=4"); // Prepare to send 4 bytes
  delay(100);
  wifiModule.println("TEST"); // Send "TEST" data

  // Read and print responses from the module
  while (wifiModule.available()) {
    String response = wifiModule.readString();
    Serial.println(response); // Print response to Serial Monitor
  }

  delay(5000); // Wait before sending the next message
}

• Replace "YourSSID" and "YourPassword" with your WiFi network credentials.
• Ensure the Arduino IDE Serial Monitor is set to the correct baud rate (9600 in this case).

1. Module Not Responding

   • Ensure the EN pin is pulled HIGH.
   • Verify the power supply is stable and within the 3.3V range.
   • Check the UART connections (TXD and RXD) for proper wiring.

2. WiFi Connection Fails

   • Double-check the SSID and password in the code.
   • Ensure the WiFi network is within range and not restricted (e.g., MAC filtering).

3. Data Transmission Errors

   • Verify the baud rate settings match between the module and the microcontroller.
   • Check for electromagnetic interference near the module.

• Use an oscilloscope or logic analyzer to monitor UART signals for debugging.
• Test the module with simple AT commands (e.g., AT, AT+RST) to verify basic functionality.
• Refer to the REYAX RYLR998 datasheet for advanced configuration options.