https://github.com/IanDBallard/CatScarer

Project Overview

CatScarer is a Arduino-based cat deterrent system that uses motion detection, multiple deterrent mechanisms, and IR remote control to keep cats away from designated areas. The device operates using a state machine with four distinct operational states, providing both automated and manual control capabilities.

🏗️ System Architecture

Core Components

• Arduino Nano (ATmega328P) - Primary microcontroller

• PIR Motion Sensor (HC-SR501) - Motion detection

• PWM Fan - Physical deterrent mechanism

• Piezo Buzzer - Audio deterrent with siren mode

• RGB LED - Multi-color status indicator

• TSOP1838 IR Receiver - Remote control input

• 3D Printed Enclosure - Professional housing

State Machine Design

🔧 Technical Implementation

State Machine States

1. WARMUP State

• Duration: 45 seconds

• Purpose: PIR sensor calibration and baseline establishment

• Visual Indicator: Blue LED flickering (500ms intervals)

• Interruptible: Yes - IR power toggle can force transition to INACTIVE

• Logic: Monitors PIR initialization status, transitions to STANDBY when complete

2. STANDBY State

• Purpose: Ready for motion detection

• Visual Indicator: Solid green LED

• Behavior: Continuously monitors PIR sensor for motion

• Interruptible: Yes - IR power toggle transitions to INACTIVE

• Transitions:

• Motion detected → ACTIVE

• Power toggle → INACTIVE

3. ACTIVE State

• Purpose: Deterrent mechanisms active

• Visual Indicator: Solid red LED

• Duration: Configurable (default: 5 seconds)

• Deterrents:

• PWM fan at full speed (255/255)

• Buzzer siren mode

• Interruptible: Yes - IR power toggle immediately stops deterrents and transitions to INACTIVE

• Timer Refresh: Motion continues to refresh activation timer

• Transitions:

• Timer expires → STANDBY

• Power toggle → INACTIVE (immediate stop)

4. INACTIVE State

• Purpose: Device disabled, ignores all PIR input

• Visual Indicator: Solid yellow LED (red + green)

• Behavior: Completely ignores motion detection

• Interruptible: Yes - IR power toggle transitions to STANDBY

• Use Case: Manual disable for maintenance, testing, or temporary deactivation