Smarthomepcb2logic

🏠 Analog Smart Environment Monitor

A Fully Analog, Microcontroller-Free Home Monitoring and Safety System

An autonomous environment monitoring platform built entirely with analog electronics, comparator logic, and discrete components — demonstrating how complex sensing, decision-making, and actuator control can be achieved without a single line of software.

🚀 Overview

The Analog Smart Environment Monitor is a multi-sensor safety and automation system designed to continuously monitor environmental conditions and respond automatically to critical events.

Unlike modern IoT solutions that rely on microcontrollers and embedded software, this project operates entirely through analog signal processing, comparator networks, diode logic, and hardware-based decision making.

The system monitors:

• 🔥 Fire and gas hazards
• 🚨 Intrusion and movement detection
• 🌡️ Temperature and ambient light conditions
• 🌱 Soil moisture and rainfall conditions

and autonomously controls:

• 💧 Water pumps
• 🌬️ Cooling fans
• 🔔 Alarm buzzer
• 💡 Automatic lighting
• 🚿 Irrigation systems

All decisions are performed directly in hardware with no firmware, operating system, or programmable logic.

🎯 Design Philosophy

Modern electronics often hide engineering complexity behind software.

This project intentionally takes the opposite approach.

Every sensing chain, priority decision, and actuator response is implemented using:

• LM393 Comparator Networks
• LM324 Analog Processing Stages
• ULN2003 Darlington Drivers
• NE555 Timing Circuits
• Diode Logic Networks
• Discrete Analog Design Techniques

The goal was to demonstrate that sophisticated environmental automation can be achieved using fundamental electronics principles alone.

⚡ System Architecture

The monitor is organized into four independent sensing chains with hardware-enforced priorities.

🔥 Fire Protection Logic

The fire detection subsystem combines:

• Flame sensor
• MQ-2 gas/smoke sensor

Both signals are processed through comparator stages and merged using a wired-AND topology.

Only when both conditions indicate danger is the fire alarm asserted.

Response

• Activates emergency water pump
• Enables alarm buzzer
• Overrides lower-priority comfort functions

This chain has absolute system priority.

🚨 Intrusion Detection Logic

Three independent sensors contribute to the intrusion subsystem:

• PIR Motion Sensor
• Sound Sensor
• Vibration Sensor

Outputs are aggregated through diode-OR logic.

Any sensor can trigger:

• Alarm buzzer
• Status indication outputs

allowing robust intrusion detection using multiple physical phenomena.

🌡️ Comfort Automation

The comfort subsystem continuously evaluates:

Temperature

Measured using an NTC thermistor comparator chain.

Ambient Light

Measured using an LDR-based comparator stage.

Outputs drive:

• Cooling fan
• Automatic room lighting

providing fully autonomous environmental control.

🌱 Garden Automation

The irrigation subsystem monitors:

• Soil moisture
• Rain conditions

Smart Rain Override

A diode-injected threshold override prevents irrigation during rainfall.

When rain is detected:

• Soil moisture logic is bypassed
• Irrigation pump is disabled

This prevents unnecessary watering and demonstrates hardware-based decision prioritization.

🔧 Hardware Architecture

The project consists of two custom-designed PCBs.

PCB 1 — Power Supply Board

A regulated dual-rail power system generating both 12 V and 5 V rails.

Features

• Input protection fuse
• Bulk filtering capacitors
• L7812 regulator stage
• L7805 regulator stage
• Power status indicators
• Dedicated output terminals

Outputs

• 12 V regulated rail
• 5 V regulated rail

PCB Characteristics

• 1 mm power traces
• Full ground-plane copper pour
• Through-hole assembly

PCB 2 — Sensor & Logic Board

The central processing board containing all sensing and decision logic.

Major Components

Functional Blocks

• Fire detection logic
• Intrusion detection logic
• Comfort automation
• Garden irrigation control
• Priority management
• Alarm generation

🔊 Alarm System

An NE555 timer configured as an astable oscillator generates a ~1 kHz alarm tone.

The buzzer is enabled by diode-OR logic from:

• FIRE_OUTPUT
• INTRUDER_ALERT

allowing multiple alarm sources to activate the same warning system.

📁 Repository Structure

ANALOG HOME DESIGN 22/
│
├── Project/
│
├── PowerSystem/
│   ├── Schematics
│   ├── PCB Layout
│   ├── Gerbers
│   ├── CNC G-Code
│
└── smarthomepcb2logic/
    ├── Schematics
    ├── PCB Layout
    ├── BOM
    ├── Gerbers
    └── CNC G-Code

🏭 Fabrication

The boards were designed and prepared for both:

Commercial PCB Manufacturing

Compatible with:

• JLCPCB
• PCBWay
• OSH Park

through exported Gerber and drill packages.

CNC Isolation Milling

Generated G-code files allow direct fabrication from copper-clad FR4 using a desktop CNC machine.

This method was used for the project's physical prototype.

📋 Bill of Materials

Major active devices include:

• LM393 Dual Comparator ×3
• LM324 Quad Op-Amp ×1
• ULN2003AN Driver Array ×1
• NE555 Timer ×1
• L7812 Voltage Regulator
• L7805 Voltage Regulator
• 5V Relay Modules ×5
• 1N4148 Signal Diodes ×6
• 10kΩ Trimpots ×7

All components are through-hole for ease of assembly, repair, and educational visibility.

✅ Validation

Before PCB fabrication, every subsystem was individually verified on breadboard:

• Comparator threshold operation
• Fire wired-AND logic
• Intrusion diode-OR aggregation
• Rain override functionality
• Relay actuation
• Fan and pump control

Hardware testing confirmed correct system behavior under all operating conditions.

📈 Project Status

🛠 Tools Used

• KiCad 9.0
• FlatCAM
• CNC Milling Machine
• Bench Power Supply
• Breadboards
• Digital Multimeter

🎓 Academic Context

Developed as a second-year Electronics Engineering project focusing on:

• Analog Electronics
• Comparator Design
• PCB Design
• Hardware Logic Implementation
• Sensor Interfacing
• Power Electronics
• CNC PCB Fabrication

📜 License

Educational and research use.

Free to study, modify, and adapt for non-commercial purposes.

👨‍💻 Author

Bergi Chromyx

Electronics Engineering Student

2026