Parking Lot Lighting System

## 1. Sensor Circuits (Input Stage)

**PIR (Passive Infrared) Sensor**

- Infrared signal detection → Conversion to voltage signal
- Amplifier circuit: Amplifies minute voltage changes using Op-Amp
- Comparator: Compares with reference voltage to output digital signal (High/Low)
- Output: 5V when motion detected, 0V when no motion

**Ultrasonic Sensor**

- Transmission: Generates 40kHz pulse signal
- Reception: Measures reflected wave time → Distance calculation
- Timer circuit: Converts pulse round-trip time to voltage
- ADC (Analog-to-Digital Converter): Converts analog voltage to digital data

**Light Sensor (CdS/Photodiode)**

- Light intensity → Resistance value or current change
- Voltage divider circuit converts illumination to voltage signal
- Generates day/night detection signal

## 2. Control Circuit (Processing Stage)

**Microcontroller (MCU) Based Control**

- Input: Receives digital/analog signals from sensors
- Processing:
- IF illumination is low (dark) AND motion detected → Turn on
- IF no motion after set time (timer setting) → Turn off
- Output: Brightness control via PWM (Pulse Width Modulation) signal

**Logic Circuit Configuration**