Arduino Bluetooth App Control: Complete Guide for Android & iOS Projects

There’s something deeply satisfying about picking up your phone and wirelessly controlling a device you built with your own hands. Arduino Bluetooth app control has become one of the most popular ways to add wireless functionality to DIY projects, and for good reason—it’s affordable, relatively straightforward to implement, and opens up endless possibilities for remote control and monitoring.

I’ve integrated Bluetooth into dozens of projects over the years, from simple LED controllers to complex robotic arms. The technology has matured significantly, and today’s options for both Android and iOS make it easier than ever to get started. This guide will walk you through everything you need to know to implement Arduino Bluetooth app control in your own projects.

Understanding Bluetooth Technology for Arduino Projects

Before diving into apps and code, it helps to understand what you’re working with. Arduino boards don’t have built-in Bluetooth capabilities (with a few exceptions like the Arduino Nano 33 BLE and Arduino R4 WiFi), so you’ll need an external Bluetooth module.

There are two main Bluetooth standards you’ll encounter in the hobby electronics world:

Bluetooth Classic (2.0/2.1) uses the Serial Port Profile (SPP) for communication. Modules like the HC-05 and HC-06 fall into this category. They’re cheap, widely available, and work great with Android devices. The catch? iOS has restricted Bluetooth Classic for non-MFi certified accessories since iOS 7, which means these modules won’t work directly with iPhones or iPads.

Bluetooth Low Energy (BLE/4.0+) is the newer standard designed for low-power applications. Modules like the HM-10, HM-11, and AT-09 support BLE and work with both Android and iOS. The trade-off is slightly more complex setup, but the cross-platform compatibility is worth it if you need iOS support.

Choosing the Right Bluetooth Module

Your choice of Bluetooth module will determine which apps and devices you can use. Here’s a quick comparison:

Module	Bluetooth Version	Role	iOS Compatible	Price Range	Best For
HC-05	2.0 Classic	Master/Slave	No	$3-6	Android-only projects, Arduino-to-Arduino
HC-06	2.0 Classic	Slave only	No	$2-5	Simple Android control
HM-10	4.0 BLE	Peripheral	Yes	$4-8	Cross-platform projects
HM-11	4.0 BLE	Peripheral	Yes	$5-10	Compact BLE applications
AT-09	4.0 BLE	Peripheral	Yes	$3-5	Budget BLE option
ESP32	Classic + BLE	Both	Yes	$5-10	Advanced projects, WiFi+Bluetooth

For most beginners, I recommend starting with the HC-05 or HC-06 if you’re working exclusively with Android. If you need iOS compatibility or want future flexibility, invest in an HM-10 from the start.

Best Apps for Arduino Bluetooth App Control

One of the biggest questions I get is “which app should I use?” The answer depends on your platform, project complexity, and whether you want a pre-built solution or custom development.

Android Bluetooth Control Apps

Android offers the widest selection of Arduino control apps, thanks to its open Bluetooth API and the prevalence of Bluetooth Classic modules.

App Name	Type	Features	Best For
Arduino Bluetooth Controller	Pre-built	Buttons, terminal, voice control, accelerometer	General control projects
Bluetooth Terminal	Terminal	Raw serial communication, logging	Testing and debugging
Bluetooth Electronics	Widget-based	Customizable gauges, buttons, graphs	Dashboard interfaces
Roboremo	Visual builder	Sliders, buttons, custom layouts	Robotics projects
MIT App Inventor	Custom app builder	Full app development, free	Custom applications

Arduino Bluetooth Controller stands out for its versatility. It includes a terminal for debugging, customizable buttons that send specific commands, voice recognition, and even accelerometer control—which is fantastic for projects like Bluetooth cars where you want to steer by tilting your phone.

Bluetooth Electronics is my personal favorite for projects that need visual feedback. You can create dashboards with gauges, graphs, and meters to display sensor data received from your Arduino.

Roboremo deserves special mention for robotics applications. Its slider interface makes it perfect for controlling servo motors—you can send position values from 0-180 just by dragging a finger across the screen.

iOS Bluetooth Control Apps

iOS options are more limited due to Apple’s Bluetooth restrictions, but there are still solid choices for BLE-based projects.

App Name	Module Support	Features	Price
ArduinoBlue/MicroBlue	HM-10/HM-11	Joystick, sliders, buttons	Free
BLExAR	CC2541-based	Serial console, custom commands	$2.99
Bluetooth for Arduino	BLE modules	Gamepad, RGB controller, custom modes	Freemium
LightBlue	Any BLE	GATT explorer, testing	Free
nRF Connect	Any BLE	Advanced BLE debugging	Free

MicroBlue (the successor to ArduinoBlue) is probably the best option for serious iOS Arduino projects. It comes with a dedicated Arduino library that handles all the communication complexity, so you can focus on your project logic rather than Bluetooth protocols. Features include joystick control, custom buttons and sliders, tilt sensing, and even a path-drawing mode for robot navigation.

BLExAR provides a straightforward serial console that mimics what you’d get with a Bluetooth terminal on Android. It’s perfect for projects where you just need to send text commands back and forth.

LightBlue and nRF Connect aren’t specifically designed for Arduino control, but they’re invaluable for testing and debugging BLE connections. If you’re having trouble getting your HM-10 to communicate, these apps let you inspect services, characteristics, and raw data.

Building Your Own App with MIT App Inventor

Pre-built apps are convenient, but sometimes you need something tailored to your specific project. That’s where MIT App Inventor comes in. It’s a free, browser-based platform that lets you create Android apps using visual block-based programming—no Java or Kotlin knowledge required.

Setting Up MIT App Inventor for Arduino Bluetooth App Control

Here’s the basic workflow for creating a Bluetooth control app:

Step 1: Create the User Interface

In the Designer view, drag components onto your screen:

• Add a ListPicker (this will show available Bluetooth devices)
• Add a BluetoothClient component (handles the actual connection)
• Add Buttons, Sliders, or other controls for your specific needs
• Add Labels for displaying status and received data

Step 2: Program the Bluetooth Connection

Switch to the Blocks view and create the connection logic:

1. When the ListPicker opens (BeforePicking), populate it with paired Bluetooth devices using BluetoothClient.AddressesAndNames
2. When a device is selected (AfterPicking), connect using BluetoothClient.Connect with the selection
3. Add error handling to display connection status

Step 3: Send Commands

For each control element, create an event handler that sends data:

• Button press → Send a specific character or string (e.g., “1” for ON, “0” for OFF)
• Slider change → Send the slider value as a number

Step 4: Receive Data (Optional)

Use a Clock component as a timer to periodically check for incoming data:

• Check BluetoothClient.BytesAvailableToReceive
• If data is available, read it with BluetoothClient.ReceiveText
• Display in a Label or process as needed

Sample Arduino Code for App Communication

On the Arduino side, the code is surprisingly simple since Bluetooth modules use standard serial communication:

#include <SoftwareSerial.h>

SoftwareSerial bluetooth(10, 11); // RX, TX pins

int ledPin = 13;

void setup() {

  Serial.begin(9600);      // USB serial for debugging

  bluetooth.begin(9600);   // Bluetooth serial

  pinMode(ledPin, OUTPUT);

}

void loop() {

  if (bluetooth.available()) {

    char command = bluetooth.read();

    if (command == ‘1’) {

      digitalWrite(ledPin, HIGH);

      bluetooth.println(“LED ON”);

    }

    else if (command == ‘0’) {

      digitalWrite(ledPin, LOW);

      bluetooth.println(“LED OFF”);

    }

  }

}

This basic structure works for both pre-built apps and custom MIT App Inventor projects. The key is matching the commands your app sends with what your Arduino code expects.

Practical Arduino Bluetooth App Control Projects

Let’s look at some real-world applications of Arduino Bluetooth app control, from beginner-friendly to more advanced.

Project 1: Bluetooth LED Controller

This is the classic starter project—control an LED (or any digital output) from your phone.

Components needed:

• Arduino Uno or Nano
• HC-05 or HC-06 Bluetooth module
• LED and 220Ω resistor
• Jumper wires

Wiring:

Bluetooth Module	Arduino
VCC	5V
GND	GND
TX	Pin 10 (Software RX)
RX	Pin 11 through voltage divider*

*The HC-05/06 RX pin is 3.3V logic. Use a voltage divider (1kΩ + 2kΩ resistors) to step down the 5V Arduino TX signal.

This simple project teaches the fundamentals that apply to every Bluetooth control application: establishing connections, sending commands, and processing them on the Arduino.

Project 2: Bluetooth-Controlled Servo Motor

Servo control is where Bluetooth really shines. You can precisely position a servo from 0-180 degrees using a smartphone slider.

Key code additions:

#include <Servo.h>

Servo myServo;

void setup() {

  myServo.attach(9);

  bluetooth.begin(9600);

}

void loop() {

  if (bluetooth.available()) {

    int angle = bluetooth.parseInt();

    if (angle >= 0 && angle <= 180) {

      myServo.write(angle);

      bluetooth.print(“Servo: “);

      bluetooth.println(angle);

    }

  }

}

This forms the basis for robotic arm control, camera gimbals, and automated door locks.

Project 3: Bluetooth RC Car

Combining motor control with directional commands creates a smartphone-controlled vehicle.

Control scheme:

App Command	Action
‘F’	Forward
‘B’	Backward
‘L’	Turn Left
‘R’	Turn Right
‘S’	Stop

Many Bluetooth controller apps support accelerometer input, letting you “steer” the car by tilting your phone—a feature that adds serious fun factor to the project.

Project 4: Home Automation Control Panel

For smart home applications, you can control multiple relays to switch lights, fans, or appliances:

Multi-device control structure:

Command	Device	Action
‘A’	Relay 1	ON
‘a’	Relay 1	OFF
‘B’	Relay 2	ON
‘b’	Relay 2	OFF
…	…	…

Using uppercase for ON and lowercase for OFF is a common convention that makes the code logic straightforward while remaining human-readable for debugging.

iOS-Specific Considerations for Bluetooth Projects

If iOS support is essential for your project, here’s what you need to know:

Use BLE modules only. The HM-10 is the most common choice. It uses the CC2541 chip and works reliably with iOS devices from iPhone 4S onward.

Expect different connection behavior. BLE connections work through services and characteristics rather than simple serial streams. Apps like MicroBlue abstract this complexity, but if you’re building custom iOS apps with Swift or Objective-C, you’ll need to work with the Core Bluetooth framework.

Power consumption is lower but so is throughput. BLE is designed for periodic data transmission, not continuous streaming. For applications sending small commands (like button presses), this is perfect. For high-speed data logging, you may need to adjust your approach.

Consider the Arduino R4 WiFi or ESP32. Both have built-in BLE support, eliminating the need for external modules and simplifying the hardware design.

Troubleshooting Common Arduino Bluetooth App Control Issues

After helping countless makers debug their Bluetooth projects, I’ve compiled the most common problems and solutions:

Connection fails or drops repeatedly:

• Check power supply—Bluetooth modules can be sensitive to voltage fluctuations
• Ensure the module’s LED is blinking (indicating discoverable mode)
• Move closer; initial pairing often requires proximity
• Reset the module by power cycling

Data received is garbled or wrong:

• Verify baud rates match (Arduino code and module configuration)
• Check wiring—TX should go to RX and vice versa
• Add delays between consecutive sends to prevent buffer overflow

App can’t find the Bluetooth module:

• For Android: Make sure Location Services are enabled (required for Bluetooth scanning on newer Android versions)
• For iOS: Confirm you’re using a BLE module, not Bluetooth Classic
• Pair the device in phone settings first before opening the app

Commands work once then stop:

• Add proper string termination in your Arduino code
• Flush the serial buffer between reads
• Check for timeout settings in your app

Useful Resources and Downloads

To help you get started quickly, here are the essential resources:

Arduino Libraries:

• SoftwareSerial (built into Arduino IDE)
• ArduinoBlue/MicroBlue library: Available through Arduino Library Manager
• BlynkSimpleSerialBLE: For Blynk app integration

App Development Platforms:

• MIT App Inventor: https://appinventor.mit.edu
• Thunkable (iOS alternative to App Inventor): https://thunkable.com

Android Apps (Google Play Store):

• Arduino Bluetooth Controller
• Bluetooth Electronics
• Roboremo
• Bluetooth Serial Monitor

iOS Apps (App Store):

• MicroBlue
• BLExAR
• LightBlue
• nRF Connect

Documentation and Datasheets:

• HC-05/HC-06 AT Command Reference
• HM-10 Datasheet and Configuration Guide
• MIT App Inventor Bluetooth Documentation

Frequently Asked Questions

Can I control Arduino with Bluetooth on iPhone?

Yes, but you need a Bluetooth Low Energy (BLE) module like the HM-10, HM-11, or AT-09. Standard Bluetooth Classic modules (HC-05, HC-06) don’t work with iOS due to Apple’s MFi restrictions. Apps like MicroBlue and BLExAR are designed specifically for Arduino BLE control on iOS.

What is the range of Bluetooth control for Arduino projects?

Most Bluetooth modules offer a range of approximately 10 meters (33 feet) in typical indoor environments with obstacles. In open spaces, the HC-05 and HM-10 can reach up to 30-100 meters depending on interference and line of sight. For longer range, you’d need to consider WiFi or RF alternatives.

Do I need to program my own app to control Arduino via Bluetooth?

No, you don’t need to create a custom app. There are many pre-built apps like Arduino Bluetooth Controller (Android) and MicroBlue (iOS/Android) that work out of the box. However, for customized interfaces or specific functionality, MIT App Inventor lets you create Android apps without traditional coding.

Why won’t my Bluetooth module connect to my phone?

Common causes include: the module needs to be paired in phone settings first, the baud rate is misconfigured, the module isn’t powered properly, or you’re trying to use a Bluetooth Classic module with an iPhone. For Android, also check that Location Services are enabled—it’s required for Bluetooth scanning on Android 6.0 and above.

Can I use Bluetooth and USB serial simultaneously on Arduino?

Yes, but with caveats. If you connect the Bluetooth module to pins 0 and 1 (hardware serial), you’ll have conflicts when uploading code—you must disconnect the Bluetooth module during uploads. Using SoftwareSerial on different pins (like 10 and 11) allows both USB debugging and Bluetooth communication to work simultaneously, which is much more practical for development.

Taking Your Arduino Bluetooth App Control Further

Once you’ve mastered basic Bluetooth control, the possibilities expand dramatically. You can create bidirectional systems where your Arduino sends sensor data back to your phone for real-time monitoring. You can integrate voice control using apps that convert speech to text commands. You can even chain multiple Arduinos together using HC-05 modules in master-slave configuration for complex distributed systems.

The combination of Arduino’s hardware flexibility and smartphone app interfaces creates a powerful platform for everything from educational projects to legitimate product prototypes. Whether you’re building a remote-controlled robot, a home automation system, or a data-logging sensor platform, Arduino Bluetooth app control provides the wireless foundation to bring your ideas to life.

Start simple, get comfortable with the basics, and then let your creativity drive the complexity. That’s always been the Arduino way, and Bluetooth connectivity just extends that philosophy into the wireless realm.