esp32-laser-security

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README

🛡️ ESP32 Multi-Bounce Laser Security System

Demo • Hardware Design • Mechanical Shroud • Firmware & Calibration • Contact

A professional, budget-friendly embedded security system built around a custom PCB and the ESP32 DevKit V1. This project utilizes an optical multi-bounce laser path bounced across real glass mirrors to form a tight perimeter grid, monitored dynamically by an onboard Light Dependent Resistor (LDR).

🚀 Key Features & Demo

Wireless Perimeter Design: The laser operates on its own isolated battery across the room, eliminating long, messy signal lines back to the controller.
Multi-Bounce Path: Supports $650\text{nm}$ red or $532\text{nm}$ green lasers, holding a sharp focal point through 4 to 5 mirror reflections.
Auto Ambient Calibration: Samples room light on boot to calculate a dynamic trigger threshold, preventing false alarms from day to night.
Dual-State LED Status: Uses a Red-Green LED array (Green for Armed, Red for Tripped) mirrored on both the board and an external header.
Hardware Reset Button: A debounced button on GPIO 18 instantly clears the alarm, silences the buzzer, and re-arms the system.

🖥️ Live Web UI Dashboard

The system hosts a real-time responsive dashboard providing live telemetry, node statuses, and toggle configurations.

Central Telemetry Instrumentation	Edge Sensor Matrix Nodes

🌐 Robust 6-Way Connection Matrix

To guarantee fail-safe alerts and zero telemetry loss, the firmware maintains six independent network connections across local and global layers:

Wi-Fi Link Status: Dual-channel monitoring covering your local gateway routing (HTTP-Local) and direct internet access (HTTP-Router).
MQTT Brokers: Redundant pub/sub data streams routed concurrently to an offline network broker (MQTT-Local) and a remote cloud cluster (MQTT-Cloud).
Ntfy Push Alerts: High-priority notification pipelines feeding instant breach logs via a self-hosted instance (NTFY-Local) and a global web server (NTFY-Global).

🛠️ Hardware Design

System Schematic

The circuit diagram maps out the ESP32 interface, sensor voltage dividers, and laser control lines for low-noise operation.

📐 Electronics Layout (Raw KiCad PCB)

The custom board features a compact form factor, dedicated mounting holes, and clear silkscreen labeling.

Front Layout	Back Layout

⚙️ Standalone Mechanical Mount

To achieve complete optical isolation and filter out ambient environmental light, a custom-molded mounting shroud was engineered.

Click to Expand | Standalone Shroud Views

Isometric View	Front View	Back View

📐 Engineering Dimensions & Tolerances

Design Specifications:

Material: Matte/Satin Dark Grey PLA (To absorb stray internal reflections)
Internal Diameter: Uniform 5.7mm corridor (Provides a 0.5mm clearance cushion for hand-soldered LDR play and FDM printing shrinkage)
Fasteners: Dual M3 clearance holes for flush mounting.

👉 Click here to view the interactive 3D Mount Model Natively on GitHub

🤝 Fully Integrated Assembly

The combined views show the mechanical shroud assembly bolted directly onto the electronic control circuit board.

Assembly Top View	Assembly Solder Side View

🔋 Power Setup

Click to Expand | Power Setup for two Paths

The system uses two separate power paths to stop electrical noise from the laser from messing with the ESP32 and sensors.

⚡ Path 1: ESP32 & Custom PCB

Powers the main controller and sensor board.

Battery (18650) ➔ TP4056 Charger (Safe charging)
TP4056 Output ➔ Boost Converter (Steps up voltage)
Boost Converter (5V) ➔ ESP32 Pin (5V) (Powers MCU)
ESP32 Pin (3.3V) ➔ Custom PCB (J2) (Powers LDR & LED)

🔦 Path 2: Standalone Laser Transmitter Node

Powers the laser module independently with zero physical connection to the main board.

100% Isolated: No shared wires or common ground loops with the ESP32-S3.
18650 Battery Powered: Runs on its own 18650 cell (~3.7V) for maximum, long-lasting brightness.
Manual Switch Control: Uses an inline rocker switch to completely cut power and save battery when off.

📂 Repository Structure

      esp32-laser-security/
      ├── src/                             # 💻 Firmware Source Code (PlatformIO)
      │   ├── main.cpp                     #   └── Main security system logic
      │   └── testing/                     #   └── Isolated hardware testing scripts
      │       └── laser-connected-esp.cpp
      │
      ├── esp32-laser-security-pcb/        # 🛠️ KiCad Hardware Design Files
      │   ├── *.kicad_sch                  #   └── Circuit schematic
      │   └── *.kicad_pcb                  #   └── PCB routing layout
      │
      ├── production/                      # 📦 Manufacturing & 3D Printing Files
      │   ├── gerbers/                     #   └── PCB manufacturing files (Gerbers)
      │   ├── 3d_printing/                 #   └── 3D-printable mount shroud (.STL / .3MF)
      │   └── step_models/                 #   └── 3D CAD assembly model (.STEP)
      │
      ├── assets/                          # 🖼️ Documentation Media
      │   ├── circuit_schematic.png        #   └── Circuit diagram for README
      │   ├── pcb_raw_*.png/jpg            #   └── 3D images of unmounted PCB
      │   ├── mount_*.jpg                  #   └── 3D images of standalone plastic mount
      │   └── pcb_assembled_*.jpg          #   └── Photos of the final assembly
      │
      ├── platformio.ini                   # ⚙️ Project configuration & libraries
      └── README.md                        # 📖 Main project documentation guide

🛠️ Hardware Requirements

Component	Quantity	Purpose
ESP32-S3 DevKitC-1 N16R8	1	Central processing unit & real-time monitoring engine
SYD1230 650nm 5mW Red Laser Module	1	Focusable transmitter node optimized for budget-friendly bouncing
Light Dependent Resistor (LDR)	1	High-sensitivity optical receiver
SFM-27 Active Piezo Buzzer (Continuous Sound)	1	3–24V high-decibel audible indicator; allows the ESP32 to cleanly drive custom dual-frequency police siren sweeps without internal timing conflicts
First-Surface Mirrors / HDD Platters	2–4	Zero-ghosting high-reflectivity corner reflection nodes
Metal Film Resistor (10 kΩ)	1	Pull-down resistor for the analog voltage divider circuit
Metal Film Resistor (330 Ω)	2	Current-limiting protection resistors (e.g., for status LEDs)
Metal Film Resistor (220 Ω)	2	Current-limiting protection resistors (e.g., for buzzer power constraints)
6x6x5mm Tactile Push Button Switch	1	PCB-mount tactile switch for instant manual system reset or calibration
7×1 Pin Male Berg Header (Straight, 10mm Height, 2.54mm Pitch)	1	Breakout interface connector for peripheral GPIO programming/debugging pins
XY126V-5.0-2P Green Screw Terminal Block (5mm Pitch, Through Hole)	1	XINLAIYA 10A 300V power connector with wire protection for external main DC input
3 Pin JST XH 2.5mm Top Entry Header (Straight Male & Female Pair)	1	Polarity-keyed locking connector for secure LDR receiver wire routing
Socket Head Cap Screw (M3x12)	2	High-strength mechanical fasteners for enclosure or PCB corner mounting
M3 Stainless Steel Hex Nut	2	Matching rust-resistant hexagonal nuts to secure the M3 mounting screws safely

🔌 Circuit Topology & Wiring

To achieve a clean optical baseline and prevent room lighting from flooding the sensor, the LDR must be housed inside an opaque, dark isolation tube pointed directly down the incoming laser path.

Central Control Unit Pinout Mapping

      +-----------------------------------------------------------------+
      |                    ESP32-S3 DevKitC-1 N16R8                     |
      +-----------------------------------------------------------------+
        | GPIO 4 (ADC) | <-------> Pin 1: LDR  (R1 Sensor Output Node)
        | GPIO 18       | <-------- Pin 2: RST  (Reset Push Button SW1)
        | GPIO 5        | --------> Pin 3: BUZZ (External Buzzer J3)
        | GPIO 19*      | --------> Pin 4: GRN  (Green LED Control Rail)
        | GPIO 21*      | --------> Pin 5: RED  (Red LED Control Rail)
        | GND           | --------> Pin 6: GND  (Common System Ground)
        | 3V3           | --------> Pin 7: 3V3  (System Power Input)

        +-----------------------------------------------------------------------------------+
        |                            EXTERNAL COMPONENT CONNECTIONS                         |
        +-----------------------------------------------------------------------------------+
        |                                                                                   |
        |  [ PCB Header J1 ] --------------------> Connects to EXTERNAL RG LED              |
        |     (EXT. RG LED)                         - Pin R: Red Indicator Anode            |
        |                                           - Pin G: Green Indicator Anode          |
        |                                           - Pin -: Common Ground Rail             |
        |                                                                                   |
        |  [ PCB Header J3 ] --------------------> Connects to EXTERNAL ACTIVE BUZZER       |
        |     (EXT. BUZZER)                         - Pin +: Positive Audio Signal Input    |
        |                                           - Pin -: Negative Ground Return         |
        |                                                                                   |
        +-----------------------------------------------------------------------------------+

3.3V Safe Voltage Divider Layout

3V3 Rail -----[ LDR ]-----+-----> GPIO 34 (Analog Read Input)
                          |
                     [ 10kΩ Resistor ]
                          |
                         GND Rail

Note: Powering the LDR network from the 3V3 rail protects the ESP32's 12-bit ADC pins from 5V over-voltage degradation.

💻 Software Configuration & Installation

This project is built using PlatformIO IDE inside VS Code for robust environment management and smaller, compiled binary footprints.

Project Environment Configuration (platformio.ini)


[env:esp32-s3-devkitc-1]
platform = espressif32
board = esp32-s3-devkitc-1
framework = arduino
monitor_speed = 115200

# Force the compiler to disable PSRAM tracking to prevent boot panics
build_flags = 
    -DBOARD_HAS_PSRAM=0
    -DARDUINO_USB_CDC_ON_BOOT=1

# Specify LittleFS partitioning layout
board_build.filesystem = littlefs

# Standard partition table for an 8MB Flash device (No PSRAM)
board_build.partitions = default_8MB.csv

lib_deps =
    esphome/ESPAsyncWebServer-esphome @ ^3.2.2
    knolleary/PubSubClient @ ^2.8

# Tell PlatformIO to compile everything in src, EXCEPT the testing folder
build_src_filter = +<*> -<testing/>

Deployment Instructions

Clone this repository to your local workspace:

git clone https://github.com/JaswantBhartiya/esp32-laser-security.git

Open the project folder directly inside Visual Studio Code with the PlatformIO extension active.
Align your external laser node across your mirror grid so it hits the center of the LDR tube.
Click the PlatformIO: Upload arrow icon on the bottom status bar (or press (Ctrl + Alt + U) to compile and flash the firmware.
Open the Serial Monitor (Ctrl + Alt + M) at 115200 baud to watch the system run its initial calibration profiling.

⚙️ How System States Work

  
           +------------------+
           | STATE_CALIBRATING| <-------- On Boot / User Reset
           +------------------+
                     |
                     v (Samples light & computes threshold)
           +------------------+
      +--->|   STATE_ARMED    |
      |    +------------------+
      |              |
      |              v (Beam broken for >50ms)
      |    +------------------+
      |    |  STATE_BREACHED  |
      |    +------------------+
      |              |
      +--------------+ (Reset Button Pressed)

Boot Calibration: Samples the laser beam for 3 seconds to calculate a dynamic trigger threshold between direct laser light and ambient room light.
Active Guard: Continuously samples the LDR. Requires the beam to be broken for over 50ms to filter out false alarms from dust or bugs.
Breached Alert: Plays a dual-tone siren sweep ($800\text{Hz}$ to $1300\text{Hz}$) on GPIO 5 using non-blocking microsecond delays.
Hardware Reset: Actively polls GPIO 18. Pressing the reset button instantly mutes the buzzer and recalibrates the system back to Armed mode.

⚙️ Calibration & Environment Tuning

🛠️ Quick Alignment Guide

Align: Aim the laser dot directly into the center of the LDR shroud.
Calibrate: Power on or reset the ESP32. Keep the laser path completely clear for the first 3 seconds.
Calculate: The firmware auto-sets the trigger threshold using a simple median formula:

$$\text{Threshold} = \frac{\text{Laser Intensity} + \text{Ambient Light}}{2}$$

Verify: Block the beam with your hand to test that it instantly triggers the alarm.

🔍 Ambient Light Troubleshooting

Issue	Root Cause	Quick Fix
Instant alarm on boot	Laser missed the LDR during calibration.	Re-align the laser and press the reset button to recalibrate.
Beam broken, no alarm	Side-glare or ambient room light is bleeding into the sensor.	Move away from windows or use a longer 3D-printed shroud to block ambient light.
Siren flickers/jitters	Laser dot is slightly misaligned or vibrating on the edge of the sensor.	Tighten your laser/mirror mounts to eliminate physical jitter.

🚀 Hardware Evolution & Development

To see the complete multi-phase development timeline—including planned v2.0 hardware protection circuits, v3.0 wireless IoT feature tracking, and long-term mechanical upgrades—view the project's growth pipeline:

👉 View the Comprehensive Project Roadmap & Future Upgrades

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

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