1. Components Needed
| Component | Purpose |
| Arduino Uno/Nano | Base microcontroller |
| ESP8266 / NodeMCU | WiFi module for internet connection |
| Sensors (DHT11, etc.) | Collect temperature/humidity data |
| Actuators (Relay, Buzzer) | Perform actions |
| IoT Platform (Thingspeak, Blynk) | Cloud storage & display |
2. Programming Arduino for IoT – Steps
Step 1: Setup Hardware
You can use either:
A. Arduino + WiFi Module (ESP8266)
- Connect ESP8266 to Arduino using serial pins
- Requires extra wiring
B. NodeMCU or ESP32 (Recommended)
- Built-in WiFi support
- No need for separate Arduino board
Step 2: Install Required Libraries
Use Arduino IDE and install:
- ESP8266WiFi.h orWiFi.h (for ESP32)
- ThingSpeak.h (for cloud)
- BlynkSimpleEsp8266.h (for Blynk app)
To install:
Sketch > Include Library > Manage Libraries → Search and install required ones.
Step 3: Connect to WiFi
Sample code to connect NodeMCU to WiFi:
#include <ESP8266WiFi.h>
const char* ssid = "YourWiFiSSID";
const char* password = "YourWiFiPassword";
void setup() {
Serial.begin(9600);
WiFi.begin(ssid, password);
Serial.print("Connecting to WiFi");
while (WiFi.status() != WL_CONNECTED) {
delay(1000);
Serial.print(".");
}
Serial.println("Connected!");
}
void loop() {
// Add sensor or cloud code here
}
Step 4: Send Data to Cloud (Example: Thingspeak)
#include <ESP8266WiFi.h>
#include "ThingSpeak.h"
const char* ssid = "YourWiFiSSID";
const char* password = "YourPassword";
WiFiClient client;
unsigned long channelID = 123456; // Your ThingSpeak Channel ID
const char* writeAPIKey = "ABC123XYZ"; // Your Write API Key
void setup() {
Serial.begin(9600);
WiFi.begin(ssid, password);
ThingSpeak.begin(client);
}
void loop() {
int value = analogRead(A0); // Read data (e.g., from sensor)
ThingSpeak.writeField(channelID, 1, value, writeAPIKey);
delay(15000); // Update every 15 sec
}
Step 5: Display or Control via Mobile App (Example: Blynk)
- Download Blynk app
- Create a new project and get the auth token
- Use it in code:
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
char auth[] = "YourBlynkToken";
char ssid[] = "YourWiFiSSID";
char pass[] = "YourPassword";
void setup() {
Blynk.begin(auth, ssid, pass);
}
void loop() {
Blynk.run();
}
Add widgets in the Blynk app to control or view sensor values.
3. IoT Projects Using Arduino
| Project Idea | Modules Used |
| Smart Weather Station | DHT11 + NodeMCU + Thingspeak |
| Home Automation via Phone | NodeMCU + Relay + Blynk |
| Smart Door Lock | RFID + NodeMCU + Firebase |
| IoT-based Soil Moisture Monitor | Soil Sensor + ESP8266 + LCD Display |
4. Platforms to Connect Arduino IoT Projects
| Platform | Purpose | Free Tier? |
| Thingspeak | IoT data logging and graphs |
|
| Blynk | IoT mobile app for control |
|
| IFTTT | Automation and alerts |
|
| Firebase | Real-time database |
|
Summary – Programming Arduino for IoT
| Step | Description |
| Connect WiFi | Use ESP8266 or NodeMCU |
| Add Libraries | WiFi, Cloud (ThingSpeak, Blynk) |
| Read Sensors | Use analogRead() or digitalRead() |
| Upload to Cloud | Send values using APIs or SDKs |
| Use Apps/Graphs | View/control via phone or web dashboards |
Basic Arduino Programs for BCA Students
1. Blink LED (Hello World of Arduino)
Purpose: Turns an LED on and off every second.
void setup() {
pinMode(13, OUTPUT); // Set pin 13 as output
}
void loop() {
digitalWrite(13, HIGH); // Turn LED ON
delay(1000); // Wait 1 second
digitalWrite(13, LOW); // Turn LED OFF
delay(1000); // Wait 1 second
}
2. LED with Button
Purpose: Turns on the LED when the button is pressed.
int button = 2;
int led = 13;
void setup() {
pinMode(button, INPUT);
pinMode(led, OUTPUT);
}
void loop() {
if (digitalRead(button) == HIGH) {
digitalWrite(led, HIGH);
} else {
digitalWrite(led, LOW);
}
}
3. Analog Sensor Reading (e.g., LDR, Potentiometer)
Purpose: Reads analog value from pin A0.
void setup() {
Serial.begin(9600);
}
void loop() {
int sensorValue = analogRead(A0);
Serial.println(sensorValue);
delay(500);
}
4. Temperature Reading using DHT11 Sensor
#include <DHT.h>
#define DHTPIN 2
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);
void setup() {
Serial.begin(9600);
dht.begin();
}
void loop() {
float temp = dht.readTemperature();
float hum = dht.readHumidity();
Serial.print("Temp: ");
Serial.print(temp);
Serial.print(" C, Humidity: ");
Serial.print(hum);
Serial.println(" %");
delay(2000);
}
5. Buzzer Alert
Purpose: Turns on buzzer for 1 second, then off.
int buzzer = 8;
void setup() {
pinMode(buzzer, OUTPUT);
}
void loop() {
digitalWrite(buzzer, HIGH);
delay(1000);
digitalWrite(buzzer, LOW);
delay(1000);
}
6. Servo Motor Control
#include <Servo.h>
Servo myservo;
void setup() {
myservo.attach(9); // Connect servo to pin 9
}
void loop() {
myservo.write(0);
delay(1000);
myservo.write(90);
delay(1000);
myservo.write(180);
delay(1000);
}