Dual-Axis Solar Tracker (AVR ATmega + I2C LCD)

This project implements a dual-axis solar tracker using an AVR ATmega microcontroller.
It reads four LDR sensors (via ADC), calculates light intensity differences, and drives two servo motors (azimuth + elevation) to align a solar panel (or any platform) toward the strongest light source.

An I2C LCD (HD44780 + PCF8574 backpack) is used to display sensor values and tracking information, and UART prints debug logs to a serial monitor.

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Features

• ✅ Dual-axis tracking (Azimuth + Elevation)
• ✅ 4× LDR sensors read using ADC channels
• ✅ Servo control using Timer1 PWM (50Hz)
• ✅ I2C LCD driver (PCF8574 backpack)
• ✅ LCD page switching (example: show sensors on page 1, angles/PWM on page 2)
• ✅ UART debug output (9600 baud)

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Hardware Requirements

• AVR ATmega MCU (example: ATmega8 / ATmega328P)
• 4× LDR sensors + voltage divider resistors
• 2× servo motors (SG90 / SG5010, etc.)
• I2C LCD module (16x2 or 20x4) with PCF8574 backpack
• External 5V supply for servos (recommended)
• Common ground between MCU and servo supply

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Wiring (Typical)

LDR Inputs (ADC)

• LDR1 → ADC0
• LDR2 → ADC1
• LDR3 → ADC2
• LDR4 → ADC3

Servo Outputs (Timer1)

• Servo Azimuth → OC1A (PB1)
• Servo Elevation→ OC1B (PB2)

I2C LCD (TWI)

• SDA → PC4 (ATmega328P) / SDA pin (depends on MCU)
• SCL → PC5 (ATmega328P) / SCL pin (depends on MCU)
• LCD I2C Address: usually 0x27 or 0x3F

UART Debug (TX)

• TX → UART RX of USB-to-TTL adapter (9600 baud)

⚠️ Servos can draw high current. Power them from a separate 5V supply and connect GND together.

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How It Works

1. Read the 4 LDR values using ADC.
2. Compute average brightness for:
   • Up vs Down
   • Left vs Right
3. Compute errors:
   • errUD = down - up
   • errLR = right - left
4. If the error exceeds a threshold, adjust servo angles by a small step.
5. Clamp angles to stay within 0..180.
6. Display values on LCD and print debug values using UART.

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Project Structure

Project/
  src/
    main.c
    i2c.c
    i2c_lcd.c
  Header Files/
    i2c.h
    i2c_lcd.h

  simulation.pdsprj
  README.md