Sensors are essential components in the Arduino environment, enabling the creation of interactive projects by allowing the Arduino to interact with the physical world. They convert physical parameters like temperature, light, distance, and pressure into electrical signals that the Arduino can read and process. This article will guide you through the basics of using sensors with Arduino, including practical examples with sample codes.

Understanding Sensors

Sensors can be broadly categorized into analog and digital sensors:

1. Analog Sensors: These sensors output a continuous voltage that corresponds to the parameter being measured. Examples include temperature sensors like the LM35 and light sensors like the photoresistor.

2. Digital Sensors: These sensors provide discrete signals, often in the form of binary data. Examples include the DHT11 temperature and humidity sensor and the HC-SR04 ultrasonic distance sensor.

Connecting Sensors to Arduino

Example 1: Using an Analog Temperature Sensor (LM35)

Components Required:

• Arduino Uno
• LM35 Temperature Sensor
• Jumper wires
• Breadboard

Wiring:

1. Connect the VCC pin of the LM35 to the 5V pin on the Arduino.
2. Connect the GND pin of the LM35 to the GND pin on the Arduino.
3. Connect the output pin of the LM35 to the A0 analog input pin on the Arduino.

Sample Code:

const int sensorPin = A0;  // Pin connected to the sensor's output
float temperature;

void setup() {
  Serial.begin(9600);
}

void loop() {
  int sensorValue = analogRead(sensorPin);
  temperature = sensorValue * (5.0 / 1023.0) * 100; // Convert the analog reading to temperature
  Serial.print("Temperature: ");
  Serial.print(temperature);
  Serial.println(" °C");
  delay(1000);
}

Example 2: Using a Digital Ultrasonic Sensor (HC-SR04)

Components Required:

• Arduino Uno
• HC-SR04 Ultrasonic Sensor
• Jumper wires
• Breadboard

Wiring:

1. Connect the VCC pin of the HC-SR04 to the 5V pin on the Arduino.
2. Connect the GND pin of the HC-SR04 to the GND pin on the Arduino.
3. Connect the TRIG pin of the HC-SR04 to digital pin 9 on the Arduino.
4. Connect the ECHO pin of the HC-SR04 to digital pin 10 on the Arduino.

Sample Code:

const int trigPin = 9;
const int echoPin = 10;
long duration;
int distance;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  Serial.begin(9600);
}

void loop() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");
  delay(1000);
}

Conclusion

Using sensors with Arduino is a straightforward process that can greatly enhance the functionality of your projects. By understanding the type of sensor and its output, you can effectively integrate it with your Arduino setup to read and process data from the physical world.