Getting Started with Arduino IoT Cloud and NodeMCU to Control an LED

Controlling an LED with NodeMCU through Arduino IoT Cloud is a fantastic beginner project that introduces you to the world of IoT (Internet of Things). Follow these simple steps to get started:

Step 1: Set Up Arduino IoT Cloud

1. Create an Arduino Account:

- Go to [Arduino Create](https://create.arduino.cc/) and sign up for a free account or log in if you already have one.

2. Access Arduino IoT Cloud:

- Navigate to the [Arduino IoT Cloud](https://create.arduino.cc/iot) from the Arduino Create dashboard.

3. Set Up a New Thing:

- Click on "Create Thing" to set up a new IoT device.

- Give your Thing a name, such as "LED_Controller."

Step 2: Configure the Device

1. Add a Device:

- Click on "Add Device" and select "Set up a third-party device."

- Choose "ESP8266" and select NodeMCU 1.0 from the list of supported boards.

2. Generate Device ID and Secret Key:

- Follow the instructions to generate a Device ID and Secret Key. Note these down as they are needed later.

3. Install the Arduino IoT Cloud Library:

- Open the Arduino IDE and install the `ArduinoIoTCloud` and `Arduino_ConnectionHandler` libraries via the Library Manager.

Step 3: Write the Code

1. Set Up the Sketch:

- Open a new sketch in the Arduino IDE.

- Include the necessary libraries at the beginning of your sketch:

 #include "thingProperties.h"

2. Define the LED Pin:

- Define the pin where the LED is connected (e.g., D2 on NodeMCU):

const int ledPin = D2;

3. Setup Function:

- Initialize the LED pin and IoT Cloud connection:

void setup() {
         // Initialize the serial and wait for the port to open:
         Serial.begin(9600);
         delay(1500); 
         initProperties();
         // Connect to Arduino IoT Cloud
         ArduinoCloud.begin(ArduinoIoTPreferredConnection);
         // Initialize LED pin
         pinMode(ledPin, OUTPUT);
         // Sync initial state
         ArduinoCloud.addCallback(ArduinoIoTPreferredCallback);
     }

4. Loop Function:

- Use the loop function to keep the connection active:

void loop() {
         ArduinoCloud.update();
     }

5. Callback Function:

- Create a function to handle the LED control:

void onLedChange() {
        digitalWrite(ledPin, ledState);
     }

Step 4: Connect and Upload

1. Connect NodeMCU:

- Connect your NodeMCU board to your computer via USB.

2. Upload the Sketch:

- Select the correct board and port from the Tools menu in the Arduino IDE.

- Click "Upload" to upload the code to your NodeMCU.

3. Configure Network Credentials:

- In the `thingProperties.h` file, enter your Wi-Fi SSID and password.

const char SSID[]     = "your_SSID";
const char PASS[]     = "your_PASSWORD";  

Step 5: Create a Dashboard

1. Add a Dashboard:

- In Arduino IoT Cloud, go to the Dashboards section and create a new dashboard.

2. Add a Widget:

- Add a switch widget to control the LED.

- Link the widget to the `ledState` variable.

3. Control Your LED:

- Use the dashboard switch to turn the LED on and off from anywhere in the world!