How to Use Adafruit Bluefruit LE UART Friend: Examples, Pinouts, and Specs

The Adafruit Bluefruit LE UART Friend is a versatile Bluetooth Low Energy (BLE) module designed for seamless wireless communication between microcontrollers, such as Arduino boards, and Bluetooth 4.0 (and later) enabled devices, including smartphones and tablets. This module can operate as either a BLE server (peripheral) or client (central), making it suitable for a wide range of applications such as remote control, data logging, and sensor monitoring.

• Wireless sensor data collection
• Smartphone-controlled gadgets and robotics
• BLE-based home automation systems
• DIY fitness trackers and health monitors
• Interactive art and wearable technology

• Bluetooth Version: Bluetooth 4.0 Low Energy (BLE)
• Frequency: 2.4 GHz ISM band
• Voltage Supply: 3.3V to 5V (with onboard voltage regulator)
• Current Consumption: 6mA (average), 26mA (peak during transmission)
• Baud Rate: 9600 bps (default, configurable up to 115200 bps)
• Range: Up to 100 meters (line of sight)
• Antenna: Built-in PCB antenna

1. Powering the Module: Connect the VIN pin to a 3.3V to 5V power supply, and the GND pin to the ground.
2. UART Communication: Connect the TXO pin of the module to the RX pin of your microcontroller, and the RXI pin to the TX pin.
3. Optional Flow Control: If required, connect the RTS and CTS pins for hardware flow control.
4. Mode Selection: The MODE pin can be pulled high to enter COMMAND mode for configuration. Otherwise, it operates in DATA mode for transparent UART communication.

• Ensure that the power supply is within the specified voltage range to prevent damage.
• Use a common ground between the Bluefruit LE UART Friend and the microcontroller.
• For reliable communication, consider using hardware flow control by connecting the RTS and CTS pins.
• When using with an Arduino UNO, remember to disconnect the RX and TX pins during the programming of the Arduino to avoid conflicts.

• Module Not Powering On: Check the power connections and ensure the voltage is within the specified range.
• No Communication: Verify that the TX and RX connections are correct and that the baud rate matches the configuration of both devices.
• Intermittent Connection: Ensure there are no sources of interference nearby and that the antenna area is not obstructed.

• Reset the Module: Sometimes simply resetting the module can resolve communication issues.
• Check LED Indicators: The onboard LEDs can provide useful information about the status of the module.
• Update Firmware: Ensure the module is running the latest firmware available from Adafruit.

#include <SoftwareSerial.h>

// Create a software serial object to communicate with the Bluefruit LE module
SoftwareSerial bluefruitSerial(10, 11); // RX, TX

void setup() {
  // Set up the serial port for debugging
  Serial.begin(9600);
  // Start communication with the Bluefruit LE module
  bluefruitSerial.begin(9600);
  Serial.println("Bluefruit LE UART Friend example");
}

void loop() {
  // Forward any data from the hardware serial to the Bluefruit LE module
  if (Serial.available()) {
    bluefruitSerial.write(Serial.read());
  }
  // Forward any data from the Bluefruit LE module to the hardware serial
  if (bluefruitSerial.available()) {
    Serial.write(bluefruitSerial.read());
  }
}

Note: The above code uses pins 10 and 11 for software serial communication with the Bluefruit LE UART Friend. Adjust the pin numbers as needed for your specific setup. Ensure that the baud rate set in bluefruitSerial.begin() matches the configured baud rate of the Bluefruit LE module.