How to Use KCX_BT_EMITTER to Bluetooth Speaker/Headphones: Examples, Pinouts, and Specs

The KCX_BT_EMITTER is a compact and efficient Bluetooth audio transmitter module designed to enable devices to wirelessly stream audio to Bluetooth-enabled speakers or headphones. This module is ideal for applications where audio needs to be transmitted without the constraints of physical connections, such as in home audio systems, portable media players, or DIY electronics projects.

• Wireless audio transmission for home entertainment systems
• Adding Bluetooth audio capabilities to non-Bluetooth devices
• DIY projects involving audio streaming
• Portable media players or gaming consoles
• Wireless audio solutions for vehicles

The KCX_BT_EMITTER module is designed for ease of use and compatibility with a wide range of devices. Below are its key technical specifications:

The KCX_BT_EMITTER module has a simple pinout for easy integration into circuits. Below is the pin configuration:

1. Power the Module: Connect the VCC pin to a 5V DC power source and the GND pin to ground.
2. Audio Input: Connect the AUDIO_L and AUDIO_R pins to the left and right audio output of your device (e.g., a media player or audio amplifier).
3. Pairing:
   • Connect a momentary push button to the KEY pin and ground. Pressing this button will put the module into pairing mode.
   • The LED pin can be connected to an LED (with a current-limiting resistor) to indicate the module's status (e.g., pairing, connected).
4. Serial Communication (Optional): Use the TXD and RXD pins for UART communication if you need to configure the module or monitor its status.

• Ensure the power supply is stable and within the specified voltage range (5V DC).
• Use shielded audio cables to minimize noise and interference in the audio signal.
• Place the module in an open area to maximize the Bluetooth transmission range.
• Avoid placing the module near sources of electromagnetic interference, such as motors or high-frequency circuits.
• If using the UART interface, configure the baud rate to 9600 bps (default) for communication.

The KCX_BT_EMITTER can be connected to an Arduino UNO for additional control or monitoring. Below is an example of how to configure the module using Arduino:

// Example code to control the KCX_BT_EMITTER module with an Arduino UNO
// This code configures the module and monitors its status via UART.

#include <SoftwareSerial.h>

// Define RX and TX pins for SoftwareSerial
SoftwareSerial BTSerial(10, 11); // RX = Pin 10, TX = Pin 11

// Define the KEY and LED pins
const int keyPin = 2;  // Pin connected to the KEY pin of the module
const int ledPin = 13; // Pin connected to the LED pin of the module

void setup() {
  // Initialize serial communication
  Serial.begin(9600);       // For debugging via Serial Monitor
  BTSerial.begin(9600);     // For communication with the KCX_BT_EMITTER

  // Configure pins
  pinMode(keyPin, OUTPUT);
  pinMode(ledPin, OUTPUT);

  // Set initial states
  digitalWrite(keyPin, HIGH); // Ensure the module is not in pairing mode
  digitalWrite(ledPin, LOW);  // Turn off the status LED
}

void loop() {
  // Example: Put the module into pairing mode when a command is received
  if (Serial.available()) {
    char command = Serial.read();
    if (command == 'P') { // 'P' for Pairing
      Serial.println("Entering pairing mode...");
      digitalWrite(keyPin, LOW);  // Activate pairing mode
      delay(2000);                // Hold for 2 seconds
      digitalWrite(keyPin, HIGH); // Exit pairing mode
    }
  }

  // Monitor the module's status via UART
  if (BTSerial.available()) {
    char status = BTSerial.read();
    Serial.print("Module Status: ");
    Serial.println(status);
  }
}

1. No Audio Output

   • Ensure the AUDIO_L and AUDIO_R pins are properly connected to the audio source.
   • Verify that the Bluetooth speaker/headphones are paired and connected to the module.

2. Bluetooth Device Not Pairing

   • Check if the module is in pairing mode (press the button connected to the KEY pin).
   • Ensure the Bluetooth speaker/headphones are within range (10 meters or less).
   • Restart both the module and the Bluetooth device.

3. Intermittent Audio or Noise

   • Use shielded cables for audio input to reduce interference.
   • Ensure there are no obstacles or sources of interference between the module and the Bluetooth device.

4. LED Not Working

   • Verify the connection between the LED pin and the LED (including the current-limiting resistor).
   • Check the module's power supply and ensure it is stable.

Q: Can the KCX_BT_EMITTER transmit audio from a microphone?
A: Yes, as long as the microphone's output is amplified to line-level signals compatible with the AUDIO_L and AUDIO_R inputs.

Q: What is the default pairing name of the module?
A: The default pairing name is typically "BT_EMITTER," but this may vary depending on the manufacturer.

Q: Can I use this module with a battery-powered device?
A: Yes, as long as the battery provides a stable 5V DC output. A voltage regulator may be required for higher voltage batteries.

Q: Is it possible to change the Bluetooth name or PIN?
A: This depends on the specific firmware of the module. If supported, you can use the UART interface to configure these settings.