Arduino MKR WiFi 1010 - DIYables Bluetooth App Chat
Overview
In this tutorial, we are going to learn how to use the Bluetooth Chat feature with the Arduino MKR WiFi 1010. The Arduino MKR WiFi 1010 is a popular choice for IoT projects that combine WiFi connectivity with wireless Bluetooth control. The chat interface lets you send text commands from your smartphone to your Arduino and receive replies back — all over BLE. This is useful for sending text commands to a deployed MKR WiFi 1010 installed inside a panel or enclosure, checking status messages on your phone, or building an interactive interface without needing a USB cable connected to the Serial Monitor.
Note: The Arduino MKR WiFi 1010 only supports BLE (Bluetooth Low Energy) for this library. It does not use Classic Bluetooth with this library. The DIYables Bluetooth App supports both BLE and Classic Bluetooth on Android, and BLE on iOS. Since this board uses BLE, the app works on both Android and iOS.
Features
- Two-Way Messaging: Send and receive text messages in real time
- Command Handling: Process text commands from the mobile app
- Serial Bridge: Forward messages between Serial Monitor and Bluetooth
- Custom Responses: Auto-reply with echoes or processed data
- Works on Android & iOS: BLE is supported on both platforms
- No Pairing Required: BLE auto-connects without manual pairing
- Low Power: BLE consumes less power than Classic Bluetooth
Hardware Preparation
| 1 | × | Arduino MKR WiFi 1010 | |
| 1 | × | Micro USB Cable |
Or you can buy the following kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables .
Additionally, some of these links are for products from our own brand, DIYables .
Arduino MKR WiFi 1010 Code
Detailed Instructions
Follow these instructions step by step:
- If this is your first time using the Arduino MKR WiFi 1010, refer to the Arduino MKR WiFi 1010 getting started guide.
- Connect the Arduino MKR WiFi 1010 board to your computer using a Micro USB cable.
- Launch the Arduino IDE on your computer.
- Select Arduino MKR WiFi 1010 board and the appropriate COM port.
- Navigate to the Libraries icon on the left bar of the Arduino IDE.
- Search "DIYables Bluetooth", then find the DIYables Bluetooth library by DIYables
- Click Install button to install the library.
- You will be asked for installing some other library dependencies
- Click Install All button to install all library dependencies.
BLE Code
- On Arduino IDE, Go to File Examples DIYables Bluetooth ArduinoBLE_Chat example, or copy the above code and paste it to the editor of Arduino IDE
/*
* DIYables Bluetooth Library - Bluetooth Chat Example
* Works with DIYables Bluetooth STEM app on Android and iOS
*
* This example demonstrates the Bluetooth Chat feature:
* - Two-way text messaging via Bluetooth
* - Receive messages from mobile app
* - Send messages to mobile app
*
* Compatible Boards:
* - Arduino UNO R4 WiFi
* - Arduino Nano 33 BLE / BLE Sense
* - Arduino Nano 33 IoT
* - Arduino MKR WiFi 1010
* - Arduino Nano RP2040 Connect
* - Any board supporting the ArduinoBLE library
*
* Setup:
* 1. Upload the sketch to your Arduino
* 2. Open Serial Monitor to see connection status and messages
* 3. Use DIYables Bluetooth App to connect and chat
*
* Tutorial: https://diyables.io/bluetooth-app
* Author: DIYables
*/
#include <DIYables_BluetoothServer.h>
#include <DIYables_BluetoothChat.h>
#include <platforms/DIYables_ArduinoBLE.h>
// BLE Configuration
const char* DEVICE_NAME = "Arduino_Chat";
const char* SERVICE_UUID = "19B10000-E8F2-537E-4F6C-D104768A1214";
const char* TX_UUID = "19B10001-E8F2-537E-4F6C-D104768A1214";
const char* RX_UUID = "19B10002-E8F2-537E-4F6C-D104768A1214";
// Create Bluetooth instances
DIYables_ArduinoBLE bluetooth(DEVICE_NAME, SERVICE_UUID, TX_UUID, RX_UUID);
DIYables_BluetoothServer bluetoothServer(bluetooth);
// Create Chat app instance
DIYables_BluetoothChat bluetoothChat;
// Variables for periodic messages
unsigned long lastMessageTime = 0;
const unsigned long MESSAGE_INTERVAL = 10000; // Send message every 10 seconds
int messageCount = 0;
void setup() {
Serial.begin(9600);
while (!Serial);
Serial.println("DIYables Bluetooth - Chat Example");
// Initialize Bluetooth server with platform-specific implementation
bluetoothServer.begin();
// Add chat app to server
bluetoothServer.addApp(&bluetoothChat);
// Set up connection event callbacks
bluetoothServer.setOnConnected([]() {
Serial.println("Bluetooth connected!");
bluetoothChat.send("Hello! Arduino is ready to chat.");
});
bluetoothServer.setOnDisconnected([]() {
Serial.println("Bluetooth disconnected!");
messageCount = 0;
});
// Set up callback for received chat messages
bluetoothChat.onChatMessage([](const String& message) {
Serial.print("Received: ");
Serial.println(message);
// Echo the message back
String response = "Echo: ";
response += message;
bluetoothChat.send(response);
// You can add custom command handling here
if (message.equalsIgnoreCase("ping")) {
bluetoothChat.send("pong!");
} else if (message.equalsIgnoreCase("status")) {
bluetoothChat.send("Arduino is running normally");
} else if (message.equalsIgnoreCase("time")) {
String timeMsg = "Uptime: ";
timeMsg += String(millis() / 1000);
timeMsg += " seconds";
bluetoothChat.send(timeMsg);
}
});
Serial.println("Waiting for Bluetooth connection...");
Serial.println("Type 'ping', 'status', or 'time' in the app to test commands");
}
void loop() {
// Handle Bluetooth server communications
bluetoothServer.loop();
// Send periodic status message (only when connected)
if (bluetooth.isConnected() && millis() - lastMessageTime >= MESSAGE_INTERVAL) {
lastMessageTime = millis();
messageCount++;
String statusMsg = "Status update #";
statusMsg += String(messageCount);
statusMsg += " - All systems operational";
bluetoothChat.send(statusMsg);
Serial.print("Sent: ");
Serial.println(statusMsg);
}
// Optional: Read from Serial and send to Bluetooth
if (Serial.available()) {
String serialMsg = Serial.readStringUntil('\n');
serialMsg.trim();
if (serialMsg.length() > 0 && bluetooth.isConnected()) {
bluetoothChat.send(serialMsg);
Serial.print("Sent from Serial: ");
Serial.println(serialMsg);
}
}
delay(10);
}
- Click Upload button on Arduino IDE to upload code to Arduino MKR WiFi 1010
- Open the Serial Monitor
- Check out the result on Serial Monitor. It looks like the below:
COM6
DIYables Bluetooth - Chat Example
Waiting for Bluetooth connection...
Autoscroll
Clear output
9600 baud
Newline
Mobile App
Note: The DIYables Bluetooth App supports both BLE and Classic Bluetooth on Android, and BLE on iOS. Since the Arduino MKR WiFi 1010 uses BLE, the app works on both Android and iOS. No manual pairing is needed for BLE — just scan and connect.
- Open the DIYables Bluetooth App
- When opening the app for the first time, it will ask for permissions. Please grant the following:
- Nearby Devices permission (Android 12+) / Bluetooth permission (iOS) - required to scan and connect to Bluetooth devices
- Location permission (Android 11 and below only) - required by older Android versions to scan for BLE devices
- Make sure Bluetooth is turned on on your phone
- On the home screen, tap the Connect button. The app will scan for BLE devices.
- Find and tap "Arduino_Chat" in the scan results to connect.
- Once connected, the app automatically goes back to the home screen. Select the Chat app from the app menu.
Note: You can tap the settings icon on the home screen to hide/show apps on the home screen. For more details, see the DIYables Bluetooth App User Manual.
- Type a message in the chat input and tap send
Now look back at the Serial Monitor on Arduino IDE. You will see:
COM6
Bluetooth connected!
Received: Hello
Autoscroll
Clear output
9600 baud
Newline
- The Arduino echoes your message back, and you can see the reply in the app chat
Creative Customization - Adapt the Code to Your Project
Handle Chat Messages
Use the onChatMessage() callback to receive and process messages typed in the app. You can define any custom command words that make sense for your project — the Arduino will react accordingly:
bluetoothChat.onChatMessage([](const String& message) {
Serial.print("Received: ");
Serial.println(message);
// Echo the message back
String response = "Echo: ";
response += message;
bluetoothChat.send(response);
// Handle custom commands
if (message.equalsIgnoreCase("ping")) {
bluetoothChat.send("pong!");
} else if (message.equalsIgnoreCase("status")) {
bluetoothChat.send("Arduino is running normally");
} else if (message.equalsIgnoreCase("time")) {
String timeMsg = "Uptime: " + String(millis() / 1000) + " seconds";
bluetoothChat.send(timeMsg);
} else {
bluetoothChat.send("Unknown command: " + message);
}
});
You can add as many custom commands as you need by adding more else if blocks. For example, add LED_ON / LED_OFF to control a pin, or READ to trigger a sensor reading — any word you type in the app becomes a command.
Send Messages from Arduino
// Send a text message to the app
bluetoothChat.send("Hello from Arduino!");
// Send sensor reading
float temp = readTemperature();
bluetoothChat.send("Temperature: " + String(temp, 1) + " °C");
Serial-to-Bluetooth Bridge
Forward messages between Serial Monitor and Bluetooth:
// In loop():
if (Serial.available()) {
String serialMsg = Serial.readStringUntil('\n');
serialMsg.trim();
if (serialMsg.length() > 0 && bluetooth.isConnected()) {
bluetoothChat.send(serialMsg);
Serial.print("Sent from Serial: ");
Serial.println(serialMsg);
}
}
Handle Connection Events
bluetoothServer.setOnConnected([]() {
Serial.println("Bluetooth connected!");
bluetoothChat.send("Hello! Arduino is ready to chat.");
});
bluetoothServer.setOnDisconnected([]() {
Serial.println("Bluetooth disconnected!");
});
How to Use the Chat
App Interface
The chat interface in the DIYables Bluetooth App provides:
- Message List: Shows sent and received messages with timestamps
- Text Input: Type messages to send to the Arduino
- Send Button: Tap to send the message
Communication Flow
- Type a message in the app → Arduino receives it via onChatMessage() callback
- Arduino processes the message and optionally sends a reply via bluetoothChat.send()
- The reply appears in the app chat window
Programming Examples
Command Handler with Relay Control
const int RELAY_PIN = 7;
bluetoothChat.onChatMessage([](const String& message) {
String cmd = message;
cmd.toUpperCase();
if (cmd == "ON") {
digitalWrite(RELAY_PIN, HIGH);
bluetoothChat.send("Relay turned ON");
} else if (cmd == "OFF") {
digitalWrite(RELAY_PIN, LOW);
bluetoothChat.send("Relay turned OFF");
} else if (cmd == "STATUS") {
int state = digitalRead(RELAY_PIN);
bluetoothChat.send("Relay is " + String(state ? "ON" : "OFF"));
} else {
bluetoothChat.send("Commands: ON, OFF, STATUS");
}
});
Sensor Query System
bluetoothChat.onChatMessage([](const String& message) {
String cmd = message;
cmd.toUpperCase();
if (cmd == "TEMP") {
float temp = readTemperature();
bluetoothChat.send("Temperature: " + String(temp, 1) + " °C");
} else if (cmd == "LIGHT") {
int light = analogRead(A0);
int percent = map(light, 0, 1023, 0, 100);
bluetoothChat.send("Light level: " + String(percent) + "%");
} else if (cmd == "ALL") {
bluetoothChat.send("=== Sensor Report ===");
bluetoothChat.send("Temp: " + String(readTemperature(), 1) + " °C");
bluetoothChat.send("Light: " + String(map(analogRead(A0), 0, 1023, 0, 100)) + "%");
bluetoothChat.send("Uptime: " + String(millis() / 1000) + "s");
} else {
bluetoothChat.send("Commands: TEMP, LIGHT, ALL");
}
});
Periodic Status Updates
unsigned long lastMessageTime = 0;
const unsigned long MESSAGE_INTERVAL = 10000; // Every 10 seconds
int messageCount = 0;
void loop() {
bluetoothServer.loop();
if (bluetooth.isConnected() && millis() - lastMessageTime >= MESSAGE_INTERVAL) {
lastMessageTime = millis();
messageCount++;
String statusMsg = "Status #" + String(messageCount) + " - All systems OK";
bluetoothChat.send(statusMsg);
}
delay(10);
}
Advanced Programming Techniques
Multi-Word Command Parsing
bluetoothChat.onChatMessage([](const String& message) {
// Parse "SET PIN 13 HIGH" style commands
if (message.startsWith("SET PIN ")) {
String rest = message.substring(8);
int spaceIdx = rest.indexOf(' ');
if (spaceIdx > 0) {
int pin = rest.substring(0, spaceIdx).toInt();
String state = rest.substring(spaceIdx + 1);
state.toUpperCase();
pinMode(pin, OUTPUT);
if (state == "HIGH") {
digitalWrite(pin, HIGH);
bluetoothChat.send("Pin " + String(pin) + " set HIGH");
} else if (state == "LOW") {
digitalWrite(pin, LOW);
bluetoothChat.send("Pin " + String(pin) + " set LOW");
}
}
}
});
Chat Logger with Timestamps
bluetoothChat.onChatMessage([](const String& message) {
unsigned long seconds = millis() / 1000;
String timestamp = "[" + String(seconds / 3600) + ":" +
String((seconds % 3600) / 60) + ":" +
String(seconds % 60) + "] ";
Serial.println(timestamp + "RX: " + message);
// Log and acknowledge
bluetoothChat.send(timestamp + "Received: " + message);
});
Troubleshooting
Common Issues
1. Cannot find the device in the app
- Make sure the Arduino MKR WiFi 1010 is powered on and the sketch is uploaded
- Ensure your phone's Bluetooth is enabled
- On Android 11 and below, also enable Location services
- Try restarting Bluetooth on your phone
2. Messages not received by Arduino
- Check Bluetooth connection status in the app
- Verify the onChatMessage callback is set up correctly
- Check Serial Monitor for any error messages
3. Arduino replies not showing in app
- Ensure bluetoothChat.send() is being called
- Check that bluetoothServer.loop() is called in the main loop
- Verify connection is still active with bluetooth.isConnected()
4. Serial Monitor shows garbled text
- Ensure baud rate in Serial Monitor matches Serial.begin(9600)
- Check that the correct board is selected in Arduino IDE
5. Connection drops frequently
- Move closer to the Arduino (reduce distance)
- Check for interference from other BLE devices
- Ensure stable USB power supply
6. Upload fails or board not recognized
- Install the latest Arduino SAMD Boards package via Boards Manager (≥ 1.8.13)
- Try a different USB cable or port
- Press the reset button on the board before uploading
Project Ideas
Communication
- Text command interface for home automation
- Serial-to-Bluetooth bridge for wireless debugging
- Remote sensor query system
- Interactive quiz or trivia game
Control Systems
- Voice-to-text relay control
- Multi-device command router
- Configuration manager via chat commands
- Firmware version reporter
Logging & Monitoring
- Event logger with timestamps
- Alarm notification system