Aim:
To use sensor input to control an output device based on conditions.

Requirements:

• Arduino Uno or Raspberry Pi Pico

• PIR motion sensor or LDR (light sensor)

• Buzzer or LED

• Jumper wires

• Breadboard

• Computer with Arduino IDE or Thonny IDE

Procedure:

1. Set Up Your Microcontroller
   • Connect your Arduino or Pico to your computer.

   • Open Arduino IDE (for Arduino) or Thonny IDE (for Pico).

2. Choose Your Sensor
   • If using PIR motion sensor: Detects movement.

   • If using LDR: Detects light levels.

3. Connect the Components
   • Vcc of sensor → 5V or 3.3V on board.

   • GND → Ground.

   • Sensor output → Digital input pin (e.g., D2).

   • Buzzer/LED → Output pin (e.g., D13) with a resistor if needed.

Write the “If-Then” Code
Example for motion sensor and buzzer (Arduino):

cpp
CopyEdit
if (digitalRead(sensorPin) == HIGH) {

    digitalWrite(buzzerPin, HIGH); // Buzzer ON

} else {

    digitalWrite(buzzerPin, LOW);  // Buzzer OFF

}

              4.Test the System

1. • Wave your hand in front of the PIR sensor — the buzzer or LED should turn ON.

   • Remove motion — it should turn OFF.

     5.Add a Second Condition

     • Example: Only alert if it’s dark AND motion is detected.

     • This requires two sensors (PIR + LDR) and nested if conditions.
       
       6.Record Your Observations

Note when the output device activates and when it stays off.