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

The Adafruit Bluefruit LE Shield is a versatile Bluetooth Low Energy (BLE) module designed for seamless integration with Arduino boards. This shield enables wireless communication between an Arduino and Bluetooth-enabled devices such as smartphones, tablets, and computers. It is ideal for a variety of applications, including wireless data transfer, remote control projects, and IoT (Internet of Things) implementations. The shield operates as either a BLE server (peripheral) or client (central), providing flexibility in designing BLE applications.

• Bluetooth Version: Bluetooth 4.0 Low Energy (BLE)
• Frequency: 2.4 GHz ISM band
• Range: Up to 10 meters (33 feet)
• Power Supply: 3.3V to 5V (from Arduino board)
• Logic Level: 3.3V (5V tolerant pins)
• Interfaces: UART/I2C/SPI
• Default UART Baud Rate: 9600 bps

1. Mounting the Shield: Place the Adafruit Bluefruit LE Shield on top of your Arduino board, ensuring that all the pins are aligned and inserted correctly.
2. Power Supply: The shield will draw power directly from the Arduino board. No additional power supply is needed.
3. UART Communication: Connect the RX and TX pins of the shield to the corresponding TX and RX pins on the Arduino for UART communication.
4. SPI Communication: If using SPI, ensure that the SPI pins (10, 11, 12, 13) are connected correctly.
5. I2C Communication: For I2C, connect A4 (SDA) and A5 (SCL) to the corresponding I2C pins on the Arduino.

• Logic Levels: The shield's pins are 5V tolerant, but it operates at 3.3V logic. Be cautious when interfacing with components that use different logic levels.
• Baud Rate: The default UART baud rate is 9600 bps. If you change the baud rate, ensure that both the Arduino and the shield are configured to the same rate.
• Mode Selection: Use pin 2 to switch between DATA mode (for transparent UART communication) and COMMAND mode (to send AT commands to the module).
• Factory Reset: Use pin 3 to reset the module to factory settings if necessary. This can be useful if you encounter issues or need to clear previous configurations.

Below is a simple example of how to use the Adafruit Bluefruit LE Shield with an Arduino UNO for UART communication:

#include <SoftwareSerial.h>

SoftwareSerial bluefruit(0, 1); // RX, TX

void setup() {
  // Start the serial communication with the shield
  bluefruit.begin(9600);
  Serial.begin(9600);
  Serial.println("Adafruit Bluefruit LE Shield ready");
}

void loop() {
  // Check if data is available to read from the BLE shield
  if (bluefruit.available()) {
    char c = bluefruit.read();
    Serial.print(c);
  }

  // Check if data is available to send to the BLE shield
  if (Serial.available()) {
    char c = Serial.read();
    bluefruit.write(c);
  }
}

Note: This example uses the SoftwareSerial library to create a serial connection on pins 0 and 1. Adjust the pin numbers as needed for your specific setup.

• No Communication: Ensure that the shield is properly seated on the Arduino and that the correct pins are used for UART, SPI, or I2C communication.
• Unexpected Resets: If the shield resets unexpectedly, check the wiring of the factory reset pin to ensure it's not being triggered inadvertently.
• Inconsistent Data Transfer: Verify that the baud rate of the Arduino's serial port matches the shield's baud rate.

• LED Indicators: Use the onboard LEDs to diagnose connection and activity status.
• AT Commands: Use AT commands in COMMAND mode to configure the shield and troubleshoot connection issues.
• Firmware Update: Ensure that the shield's firmware is up to date with the latest version from Adafruit.

Q: Can I use the Adafruit Bluefruit LE Shield with other Arduino boards? A: Yes, the shield is compatible with most Arduino boards that support the required communication protocols (UART, SPI, I2C).

Q: How do I change the shield's baud rate? A: You can change the baud rate using AT commands in COMMAND mode. Refer to the Adafruit Bluefruit LE Shield documentation for specific commands.

Q: Can the shield be used for BLE central and peripheral roles? A: Yes, the shield can function in both central and peripheral roles, allowing it to initiate connections and accept incoming connections.

For more detailed information and advanced usage, refer to the official Adafruit Bluefruit LE Shield documentation and resources available on the Adafruit website.