Push notifications are an essential feature in modern IoT applications, enabling real-time alerts and updates. Integrating push notifications with Arduino can significantly enhance the functionality of your projects by allowing them to communicate important information directly to your smartphone or other devices. This article will guide you through the process of setting up push notifications in an Arduino environment using the Blynk platform, which simplifies the integration of IoT devices with mobile applications.

Project: In this project, we will create a temperature monitoring system using an Arduino board and a DHT11 temperature and humidity sensor. The system will send a push notification to a smartphone when the temperature exceeds a predefined threshold. This project demonstrates how to use the Blynk platform to send push notifications, providing a practical example of how IoT devices can interact with users in real time.

Components List:

• Arduino Uno (1)
• DHT11 Temperature and Humidity Sensor (1)
• Breadboard (1)
• Jumper Wires (several)
• USB Cable (1)
• Smartphone with Blynk App (1)

Examples:

1. Setting Up the Blynk App:

   • Download and install the Blynk app on your smartphone.
   • Create a new project in the Blynk app and obtain the Auth Token.
   • Add a "Push Notification" widget to your project.

2. Arduino Code:

   
   // Include necessary libraries
   #include <Adafruit_Sensor.h>
   #include <DHT.h>
   #include <DHT_U.h>
   #include <BlynkSimpleSerial.h>

// Define the DHT sensor and pin

define DHTPIN 2

define DHTTYPE DHT11

DHT dht(DHTPIN, DHTTYPE);

// Blynk Auth Token char auth[] = "YourAuthToken";

// Threshold temperature for notification float thresholdTemp = 30.0;

void setup() { // Initialize serial communication Serial.begin(9600);

// Initialize Blynk Blynk.begin(auth, Serial);

// Initialize the DHT sensor dht.begin(); }

void loop() { // Run Blynk Blynk.run();

// Read temperature from DHT11 sensor float temp = dht.readTemperature();

// Check if reading is valid if (isnan(temp)) { Serial.println("Failed to read from DHT sensor!"); return; }

// Print temperature to Serial Monitor Serial.print("Temperature: "); Serial.println(temp);

// Send push notification if temperature exceeds threshold if (temp > thresholdTemp) { Blynk.notify("Warning: Temperature is above threshold!"); }

// Wait for 2 seconds before next reading delay(2000); }

**Explanation of the Code:**
- **Libraries:** The code includes libraries for the DHT sensor and Blynk.
- **DHT Sensor Setup:** The DHT sensor is initialized on pin 2.
- **Blynk Auth Token:** Replace `"YourAuthToken"` with the Auth Token from the Blynk app.
- **Threshold Temperature:** The threshold temperature is set to 30.0 degrees Celsius.
- **Setup Function:** Initializes serial communication, Blynk, and the DHT sensor.
- **Loop Function:** Continuously reads the temperature, prints it to the Serial Monitor, and sends a push notification if the temperature exceeds the threshold.