Arduino Server doesn't see that App Inventor App has disconnect

MIT App Inventor Help
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LED_Control_HM10.aia (157.0 KB)

#include <ArduinoBLE.h>
#include <String>

BLEService nanoService("0000ffe1-0000-1000-8000-00805f9b34fb"); // BLE LED Service

// BLE LED Switch Characteristic - custom 128-bit UUID, read and writable by central
String test = "gaming";

BLEByteCharacteristic bleRW("0000ffe0-0000-1000-8000-00805f9b34fb", BLERead | BLEWrite);
BLEStringCharacteristic sdSend("0000ffe2-0000-1000-8000-00805f9b34fb", BLERead | BLEWrite , test.length());


void setup() {
  Serial.begin(9600);
  while (!Serial);

  // set LED's pin to output mode
  pinMode(LED_BUILTIN, OUTPUT);

  digitalWrite(LED_BUILTIN, LOW);         // when the central disconnects, turn off the LED

  // begin initialization
  if (!BLE.begin()) {
    Serial.println("starting BLE failed!");

    while (1);
  }

  // set advertised local name and service UUID:
  BLE.setLocalName("Nano 33 BLE Sense");
  BLE.setAdvertisedService(nanoService);

  // add the characteristic to the service
  nanoService.addCharacteristic(bleRW);
  nanoService.addCharacteristic(sdSend);

  // add service
  BLE.addService(nanoService);

  // set the initial value for the characteristic:
  bleRW.writeValue('0');
  // start advertising
  BLE.advertise();

  Serial.println("Arduino BLE");
}

void loop() {
  // listen for BLE 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 (bleRW.written()) {
        switch (bleRW.value()) {   // any value other than 0
          case 1:
            Serial.println("LED on");
            digitalWrite(LED_BUILTIN, HIGH);          // will turn the LED off
            break;

          case 2:
            Serial.println(F("LED off"));
            digitalWrite(LED_BUILTIN, LOW);          // will turn the LED off
            break;
          case 3:
            bleRW.writeValue((byte)0x05);
            sdSend.writeValue((String)test);
            Serial.println("Handshake initiated");.
            break;
        }
      }
    }

    // when the central disconnects, print it out:
    Serial.print(F("Disconnected from central: "));
    Serial.println(central.address());
    digitalWrite(LED_BUILTIN, LOW);         // when the central disconnects, turn off the LED
  }
}

I am making a simple test app to send and receive BLE data between my Arduino Nano 33 BLE Sense and an Android phone.

One issue I am facing right now is that when I press disconnect on my app, the phone disconnects but the Arduino thinks it is still connected. This is irritating as I have to reupload the Arduino to reset the BLE (pressing the physical reset button doesn't seem to work sadly).

What am I missing?

2

Can you set up a message recognized by the Arduino for the app to say 'Goodbye!'?

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