Smart Public Toilet Monitoring System

Next.js Web App

This repository now includes a Next.js app for the three AirLoo web flows:

• Public search — visitors can search shops/locations and open a shop sensor dashboard.
• Shop owner console — approved owners log in, review their shop details, and manage sensor/location data.
• Admin console — the AirLoo team can see and manage all shops, owners, devices, and alerts.

Quick start

npm install
npm run dev

Create .env.local from .env.local.example and fill in your Firebase web app values.

Auth

• Email/password login on /admin and /owner
• Google Sign-In (one-click via Firebase) available on both login pages
• Sessions persist across page refreshes and expire after 30 minutes of inactivity

Data

All shops, sensors, and events are fetched live from Firestore (no mock/hardcoded data). The /api/join endpoint writes onboarding requests to Firestore and can trigger the Firebase Trigger Email extension.

Overview

The Smart Public Toilet Monitoring System is an IoT-enabled sanitation management solution designed to improve hygiene standards, maintenance efficiency, and user experience in public restroom facilities.

The system uses a magnetic door switch to monitor usage frequency and a BME680 environmental sensor to measure air quality, temperature, humidity, and odor-related gas conditions. Real-time data is transmitted to a monitoring dashboard where maintenance teams can receive alerts and respond promptly.

This solution supports condition-based cleaning rather than fixed maintenance schedules, leading to cleaner facilities and better resource utilization.

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Problem Statement

Public toilets often suffer from:

• Poor hygiene standards
• Delayed cleaning response
• Unpleasant odor
• Overuse without maintenance
• Lack of usage analytics
• Inefficient manual inspection systems

Traditional cleaning schedules are usually time-based rather than need-based, resulting in poor operational efficiency and unsatisfactory user experience.

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Proposed Solution

This project introduces a smart monitoring system capable of:

• Detecting toilet usage through door activity
• Monitoring environmental conditions continuously
• Identifying odor buildup and poor air quality
• Sending maintenance alerts automatically
• Recording historical usage data
• Supporting data-driven cleaning schedules

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System Components

Component	Function
ESP32	Main controller with Wi-Fi
Magnetic Door Switch	Detects door open/close cycles
BME680 Sensor	Measures air quality, gas, humidity, temperature
Power Supply	Powers the device
OLED Display (Optional)	Displays local status

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Working Principle

Usage Detection

A magnetic switch is mounted on the toilet door. Each door open-close cycle is treated as a usage event.

Environmental Monitoring

The BME680 continuously measures:

• Temperature
• Humidity
• Atmospheric Pressure
• Gas Resistance (used as odor / air quality indicator)

Alert Mechanism

When:

• Usage exceeds threshold
• Odor level increases significantly
• Humidity remains abnormal

The system generates a maintenance alert.

Cloud Dashboard

Sensor data is uploaded through Wi-Fi to a dashboard for monitoring and analytics.

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Features

• Real-time monitoring
• Door usage counter
• Odor detection
• Air quality monitoring
• Remote dashboard access
• Automated cleaning alerts
• Historical data logging
• Scalable multi-location deployment
• WiFi Manager with password-protected config portal
• Over-the-air WiFi reconfiguration

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Applications

• Municipal public toilets
• Railway stations
• Bus terminals
• Airports
• Shopping malls
• Educational institutions
• Hospitals
• Smart city sanitation systems

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Benefits

• Improved hygiene standards
• Faster maintenance response
• Reduced manual inspections
• Better manpower allocation
• Increased user satisfaction
• Data-driven operations

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Technology Stack

Hardware

• ESP32
• BME680 Sensor
• Magnetic Reed Switch

Software

• Arduino IDE
• Next.js / React / TypeScript Web App
• Firebase / Cloud Database
• Vercel / Static Export Deployment

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Installation

Hardware Setup

1. Connect BME680 via I2C (SDA→GPIO21, SCL→GPIO22)
2. Connect magnetic reed switch to GPIO4 (RTC GPIO — required for deep sleep wake)
3. Power ESP32 using USB, adapter, or battery (Li-ion 18650 + TP4056)
4. Mount sensors inside toilet enclosure safely

Software Setup

1. Upload firmware to ESP32 via Arduino IDE
2. On first boot, ESP32 creates a Wi-Fi access point named AirLoo-Config
3. Connect to that AP and open http://192.168.4.1 in your browser
4. Select your Wi-Fi network, enter credentials, and set an admin password
5. ESP32 reboots and connects to your network automatically

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WiFi Manager — Configuration Portal

The ESP32 includes a built-in WiFi Manager that eliminates the need to hardcode Wi-Fi credentials.

First-Time Setup

1. Power on the ESP32
2. Connect your phone/laptop to the AirLoo-Config Wi-Fi AP
3. Open a browser to http://192.168.4.1
4. Select your Wi-Fi network from the scanned list
5. Enter your Wi-Fi password
6. Create an admin password (min 4 characters) to protect the config portal
7. Click "Connect" — the device saves credentials and reboots

Reconfiguring Wi-Fi Later

• Hold the BOOT button (GPIO0) for 5 seconds during normal operation
• The device restarts into config portal mode
• Enter your admin password when prompted, then change Wi-Fi settings

Factory Reset

• Hold the BOOT button while powering on the device
• This clears all saved data (Wi-Fi credentials + admin password)
• Device boots into first-time setup mode

Security

Threat	Protection
Someone holds BOOT button	Config portal starts but admin password is required to make changes
Random person connects to AirLoo-Config	Sees a login page — can't proceed without the password
Physical tampering	Full factory reset requires holding BOOT at the moment of power-on

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Configuration

ESP32 Firmware (secrets.h)

The ESP32 firmware only needs the Firebase API key in Firebase/secrets.h.
Wi-Fi credentials are configured through the web portal (not stored in code).

Use Firebase/secrets.h.example as a template:

#define API_KEY "your_firebase_api_key"

Rename the example file and fill in your values:

cp Firebase/secrets.h.example Firebase/secrets.h

This file is gitignored to prevent accidental credential leaks.

Firebase Project ID

The Firebase project ID is configured directly in Firebase/Firebase.ino:

String projectId = "your-firebase-project-id";

Web App

The monitoring dashboard is built with Next.js (React / TypeScript) and uses Firebase for auth and data.

Firebase credentials are configured via environment variables (never committed to the repo).

cp .env.local.example .env.local

Variable	Description
NEXT_PUBLIC_FIREBASE_API_KEY	Firebase API key
NEXT_PUBLIC_FIREBASE_AUTH_DOMAIN	Firebase auth domain
NEXT_PUBLIC_FIREBASE_PROJECT_ID	Firebase project ID
NEXT_PUBLIC_FIREBASE_STORAGE_BUCKET	Firebase storage bucket
NEXT_PUBLIC_FIREBASE_MESSAGING_SENDER_ID	Firebase sender ID
NEXT_PUBLIC_FIREBASE_APP_ID	Firebase app ID
NEXT_PUBLIC_ADMIN_EMAILS	Comma-separated emails allowed in /admin
AIRLOO_JOIN_EMAIL	Sender email for join requests
FIREBASE_MAIL_COLLECTION	Firestore collection for Trigger Email

Build and deploy:

npm run build     # production build
npm run dev       # local development

The app can be deployed to Vercel or exported as a static site.

Note: Firebase Google Sign-In must be enabled in the Firebase Console (Authentication → Sign-in method → Google). Email/password sign-in works out of the box.

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Button Controls Summary

Action	GPIO	Behavior
Hold BOOT 5s (operation)	GPIO0	Restarts config portal (password required)
Hold BOOT on power-up	GPIO0	Factory reset (clears all saved data)

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Battery Operation

The firmware is optimized for deep-sleep battery operation using esp_sleep_enable_ext0_wakeup on GPIO4 (reed switch).

Power Architecture

• ESP32 spends 99%+ of time in deep sleep (~10 µA)
• Reed switch state change (GPIO4, RTC GPIO) wakes the ESP32
• ESP32 boots, connects WiFi, sends event to Firestore, shows OLED for 3s, then goes back to sleep
• Wake level alternates between HIGH/LOW to detect both OPEN and CLOSE events
• OLED is powered off via command (SSD1306_DISPLAYOFF) before sleep
• WiFi is fully disconnected and radio turned off before sleep
• CPU runs at 80 MHz to reduce active power draw
• Modem sleep enabled during WiFi idle (WiFi.setSleep(true))

Estimated Battery Life

Events/day	Active time	Avg current	Battery life (2000 mAh)
50	~4 min	~0.8 mA	~100 days
100	~8 min	~1.6 mA	~50 days
200	~17 min	~3.2 mA	~25 days

Assumes ~3s WiFi connect + ~3s OLED display per event. Actual life depends on WiFi signal strength and battery chemistry (Li-ion recommended).

Cold Boot (Power On)

On a cold boot (not from deep sleep), the firmware:

1. Shows the current door state on OLED
2. Goes to deep sleep without sending a false event
3. Normal door events trigger wake + send as usual

Battery Tips

• Use a Li-ion 18650 (2000–3000 mAh) with a TP4056 charger module
• Add a P-channel MOSFET to cut OLED power completely during sleep (the software OFF command still has ~1 µA leakage)
• Keep WiFi signal strong — weak signal increases connection time and power draw
• Disable the OLED in secrets.h if not needed (comment out the display code)
• For extreme battery life, consider batching events and sending every N wakes instead of each event

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Future Enhancements

• Water level monitoring
• Soap / tissue stock detection
• QR code feedback system
• Predictive maintenance using AI
• GSM / SMS alerts
• Integration with city control rooms

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Conclusion

The Smart Public Toilet Monitoring System offers a practical and scalable solution for improving sanitation infrastructure. By combining occupancy monitoring and environmental sensing, the system enables proactive maintenance, cleaner facilities, and more efficient public service delivery.

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License

This project is intended for educational, research, and smart city development purposes.