README generated by Copilot[Claude Haiku 4.5]! (few manual edits though)

An automated pet feeder with programmable feeding times using the LPC2378 microcontroller. It makes use of a servo motor which assists in dispensing food at the required interval and an ultrasonic sensor which helps with identifying the presence of a pet. The user may pre-feed the specific times at which the food is to be dispensed along with certain buffer interval during which the presence of a pet would be monitored. This project combines real-time scheduling, pet detection via ultrasonic sensing, and automated food dispensing with servo motor control.

• Programmable Feeding Schedule: Set specific feeding times at which food is to be dispensed
• Pet Detection: Ultrasonic HC-SR04 sensor monitors for pet presence within configurable buffer intervals
• Automatic Dispensing: PWM-controlled MG995 servo motor actuates the feeder mechanism
• Real-Time Display: 4-bit LCD displays current time, distance, and system status
• Timing Validation: Ensures pets are present before dispensing food

The following major components are used:

• NXP LPC2378 - ARM Cortex-M3 32-bit microcontroller

  • 12 MHz XTAL with PLL → 48 MHz processor clock
  • 12 MHz peripheral clock
  • Flash-based program storage

• Tower Pro MG995 Servo Motor - PWM-controlled food dispenser

  • 50 Hz frequency (20ms period)
  • Duty cycle control: 5% (closed) to 10% (fully open)

• HC-SR04 Ultrasonic Sensor - Pet presence detection

  • GPIO-based trigger and echo measurement
  • Timer1 microsecond-precision measurements
  • Configurable detection range (1-30 cm)

• 4-bit LCD Display - System feedback

  • Shows current time (HH:MM:SS)
  • Displays distance measurements
  • Status indicators

The program directory is highlighted below:

The main module is present in main.c. It controls the other modules spread across independent files with self explanatory names.

main.c - Main feeding control logic

• Implements the core feeding algorithm
• Coordinates sensor inputs and actuator outputs
• Manages feeding schedule and pet presence validation

RTC.c - Real-Time Clock (Timer0-based)

• 1ms interrupt tick generation
• Maintains hour, minute, second counters
• Displays formatted time on LCD

// Timer0: 1ms interrupts at 12 MHz peripheral clock
T0MR0 = 11999;  // 1msec interval
T0MCR = 3;      // Interrupt and Reset on Match

Servo_MG995.c - PWM Servo Control

• 50 Hz PWM frequency (240kHz base timer)
• Duty cycle mapping:
  • 5% = 0° (closed/dispenser off)
  • 7.5% = 90° (opening position)
  • 10% = 180° (fully open)

PWM1MR0 = 240000;                    // 20ms period (50 Hz)
PWM1MR1 = (dutyCycle * PWM1MR0) / 100; // Set pulse width

Ultrasonic_HC_SR04.c - Distance Sensor Driver

• Timer1-based microsecond precision timing
• 10µs trigger pulse on P0.2
• Echo measurement on P0.3
• Distance formula: distance = (0.0343 * echoTime) / 2

sendPulse(n);                 // Generate trigger pulse
distance = calDistance(m);    // Measure echo time and calculate

LCD_4bit.c - 4-bit LCD Display Driver

• GPIO-based parallel interface
• Character display and cursor control
• Formatting utilities for time/distance output

IRQ.c - Interrupt Handler

• Timer0 interrupt service routine
• Manages 1ms clock tick generation

LPC2300.s - ARM Cortex-M3 Startup Code

• Vector table initialization
• Hardware setup sequence
• Entry point to main()

The main feeding algorithm operates in a continuous loop with 1-second intervals:

Loop every second:
  1. Update RTC counter (increment seconds)
  2. Send ultrasonic trigger pulse to HC-SR04
  3. Calculate distance to pet (echo time measurement)
  4. Check if current time matches feeding schedule

  If feeding_time AND pet_present (distance < 30cm):
    - Capture current second as dispense timestamp
    - Set servo to 7.5% duty cycle (open position)
    - Mark food as dispensed
  
  If 2 seconds have elapsed since dispense:
    - Return servo to 5% duty cycle (closed)
    - Reset dispense flag
  
  Update LCD Display:
    - Current distance and release time counter
    - Current time in HH:MM:SS format
    - Clear and refresh for next cycle

• Keil MDK (µVision 4+) or equivalent ARM compiler
• LPC2378 JTAG/Flash programmer
• Target board: MCB2300 Evaluation Board (or compatible)