UNO R4 TUTORILAL0(BLE)

 /*　BLE　LEDオンオフ　サンファウンダのサイト*/

#include <ArduinoBLE.h>

BLEService ledService("19B10000-E8F2-537E-4F6C-D104768A1214"); // Bluetooth® Low Energy LED Service

// Bluetooth® Low Energy LED Switch Characteristic - custom 128-bit UUID, read and writable by central

BLEByteCharacteristic switchCharacteristic("19B10001-E8F2-537E-4F6C-D104768A1214", BLERead | BLEWrite); 　//　バイト単位の読み書きが可能となる

const int ledPin = LED_BUILTIN; // pin to use for the LED

void setup() {

  Serial.begin(9600);

  while (!Serial);

  // set LED pin to output mode

  pinMode(ledPin, OUTPUT);

  // begin initialization

  if (!BLE.begin()) {

    Serial.println("starting Bluetooth® Low Energy module failed!");

    while (1);

  }

  // set advertised local name and service UUID:

  BLE.setLocalName("UNO R4 LED");

  BLE.setAdvertisedService(ledService);

  // add the characteristic to the service

  ledService.addCharacteristic(switchCharacteristic);

  // add service

  BLE.addService(ledService);

  // set the initial value for the characeristic:

  switchCharacteristic.writeValue(0);

  // start advertising

  BLE.advertise();

  Serial.println("BLE LED Peripheral");

}

void loop() {

  // listen for Bluetooth® Low Energy peripherals to connect:

  BLEDevice central = BLE.central();

  // if a central is connected to peripheral:

  if (central) {

    Serial.print("Connected to central: ");

    // print the central's MAC address:

    Serial.println(central.address());

    // while the central is still connected to peripheral:

    while (central.connected()) {

      // if the remote device wrote to the characteristic,

      // use the value to control the LED:

      if (switchCharacteristic.written()) {

        if (switchCharacteristic.value()) {   // any value other than 0

          Serial.println("LED on");

          digitalWrite(ledPin, HIGH);         // will turn the LED on

        } else {                              // a 0 value

          Serial.println(F("LED off"));

          digitalWrite(ledPin, LOW);          // will turn the LED off

        }

      }

    }

    // when the central disconnects, print it out:

    Serial.print(F("Disconnected from central: "));

    Serial.println(central.address());

  }

}

注：Light Blueでbuiltin ledをオンオフできる

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