Run-time error - BLE app for Arduino Nano 33 IoT

I am working on a project trying to build a app to read datas from an Arduino. I used MIT appinventor and am working with a Arduino Nano 33 IOT.

I have attached the code bellow (used the example code - Battery monitor)

> /*
  Battery Monitor

  This example creates a BLE peripheral with the standard battery service and
  level characteristic. The A0 pin is used to calculate the battery level.

  The circuit:
  - Arduino MKR WiFi 1010, Arduino Uno WiFi Rev2 board, Arduino Nano 33 IoT,
    Arduino Nano 33 BLE, or Arduino Nano 33 BLE Sense board.

  You can use a generic BLE central app, like LightBlue (iOS and Android) or
  nRF Connect (Android), to interact with the services and characteristics
  created in this sketch.

  This example code is in the public domain.

#include <ArduinoBLE.h>

 // BLE Battery Service
BLEService batteryService("180F");

// BLE Battery Level Characteristic
BLEUnsignedCharCharacteristic batteryLevelChar("2A19",  // standard 16-bit characteristic UUID
    BLERead | BLENotify); // remote clients will be able to get notifications if this characteristic changes

int oldBatteryLevel = 0;  // last battery level reading from analog input
long previousMillis = 0;  // last time the battery level was checked, in ms

void setup() {
  Serial.begin(9600);    // initialize serial communication
  while (!Serial);

  pinMode(LED_BUILTIN, OUTPUT); // initialize the built-in LED pin to indicate when a central is connected

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

    while (1);

  /* Set a local name for the BLE device
     This name will appear in advertising packets
     and can be used by remote devices to identify this BLE device
     The name can be changed but maybe be truncated based on space left in advertisement packet
  BLE.setAdvertisedService(batteryService); // add the service UUID
  batteryService.addCharacteristic(batteryLevelChar); // add the battery level characteristic
  BLE.addService(batteryService); // Add the battery service
  batteryLevelChar.writeValue(oldBatteryLevel); // set initial value for this characteristic

  /* Start advertising BLE.  It will start continuously transmitting BLE
     advertising packets and will be visible to remote BLE central devices
     until it receives a new connection */

  // start advertising

  Serial.println("Bluetooth device active, waiting for connections...");

void loop() {
  // wait for a BLE central
  BLEDevice central = BLE.central();

  // if a central is connected to the peripheral:
  if (central) {
    Serial.print("Connected to central: ");
    // print the central's BT address:
    // turn on the LED to indicate the connection:
    digitalWrite(LED_BUILTIN, HIGH);

    // check the battery level every 200ms
    // while the central is connected:
    while (central.connected()) {
      long currentMillis = millis();
      // if 200ms have passed, check the battery level:
      if (currentMillis - previousMillis >= 200) {
        previousMillis = currentMillis;
    // when the central disconnects, turn off the LED:
    digitalWrite(LED_BUILTIN, LOW);
    Serial.print("Disconnected from central: ");

void updateBatteryLevel() {
  /* Read the current voltage level on the A0 analog input pin.
     This is used here to simulate the charge level of a battery.
  int battery = analogRead(A6);
  int batteryLevel = map(battery, 0, 1023, 0, 100);

  if (batteryLevel != oldBatteryLevel) {      // if the battery level has changed
    Serial.print("Battery Level % is now: "); // print it
    batteryLevelChar.writeValue(batteryLevel);  // and update the battery level characteristic
    oldBatteryLevel = batteryLevel;           // save the level for next comparison

Using the MIT app inventor, I built an app. I've attached screenshots of the app screen and the block code.

While using the app, it comes up with a run time error while trying to connect to the Arduino Nano 33 Ito through the bluetooth app that I built. Can someone please help me resolve this issue?

Hello Cloud

We need to see the exact error message. Also:
Right-mouse in the Blocks work area and select "Download Blocks as image"

What is that Arduino101Pins1 component?
Where did you get it?

Hi, I downloaded an extension - Arduino 101 and I found the pin there. thought I could use it to read the values at the pins of the Arduino. I am trying to read the value at A6 pin where there is a voltage divider connected.

Hi Chris,
Ive attached the image of the blocks b elow.. Also took a screenshot of the error message..

Well, although we can't see all your Blocks (!) , the Error Message is clear - you are using UUIDs in the App which are not the UUIDs of your Arduino BLE Hardware/Sketch.

Hello, I kindly comment that the EXT arduino101pins is to be used only with the Arduino 101 board and is not compatible with the NANO 33 BLE, in this link is a tutorial on how to use the Arduino 101:

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