Smart Home Thesis — Backend

This repository contains the backend implementation for an engineering thesis project focused on smart-home automation. The backend is built with Node.js and Express, and is designed to run on a Raspberry Pi (or compatible single-board computer) connected to sensors, actuators, and a local MySQL database.

Year of Completion

2022

Highlights

• REST API for managing and monitoring sensors and actuators — including temperature, humidity, PIR alarm, buzzer, individual lights, lighting groups, and servo-driven devices (e.g. blinds and gates).
• Optimized for Raspberry Pi, using I²C PWM drivers and GPIO interfaces for direct hardware control.
• Persistent storage handled by MySQL (tables inferred from the code: Users, Sensors, Lights, Servos, Temperature, Humidity).

Requirements

• Raspberry Pi (or compatible SBC) running Raspberry Pi OS or another Linux distribution.
• Node.js 16+ (check for compatibility with native modules used by hardware drivers).
• MySQL server (local or network). The code expects a MySQL-compatible database.
• I²C interface enabled on Raspberry Pi for PWM/servo communication.

Environment variables

The application loads environment variables from config/.env (see index.js). Use that file to store secrets and runtime configuration. Create config/.env with at least these values (names match variables used in the code):

• TOKEN_KEY=your_jwt_secret
• DB_HOST=127.0.0.1
• DB_PORT=3306
• DB_USER=root
• DB_PASS=your_password
• DB_NAME=smart_home
• DB_CONNECTION_LIMIT=10
• SERVER_PORT=3000

The code uses mysql2/mysql2-promise to connect to MySQL.

Installation

1. Clone the repository to your Raspberry Pi.
2. Install dependencies:

npm install

3. Create the database and tables using the provided schema.sql (or adapt it to your needs). Example using mysql client:

mysql -u root -p < schema.sql

4. Create .env and fill environment variables.
5. Start the server:

npm start

During development you can use npm run dev (nodemon).

API — Endpoints (summary)

• Users

  • GET /users/ — list users (id, name, surname, username, email, role)
  • GET /users/:id — get user by id
  • POST /users/sign-up — create new user (body: name, surname, username, email, password, password_confirm, role)
  • POST /users/sign-in — login (body: email, password) — returns JWT token and user info
  • PUT /users/:id — update user
  • DELETE /users/:id — delete user

• Air

  • GET /air/temperature — read current temperature from sensor
  • GET /air/humidity — read current humidity from sensor
  • GET /air/temperature/stats?start=...&end=... — historical temperature records between timestamps
  • GET /air/humidity/stats?start=...&end=... — historical humidity records between timestamps

• Alarm

  • GET /alarm/state — read PIR and Buzzer sensor states
  • PUT /alarm/ — turn alarm on/off (body: { enabled: true/false })

• Light (single sensor)

  • GET /light/state — read light sensor state
  • PUT /light/ — toggle physical light sensor (body: { enabled: true/false })

• Lighting (multiple lights / groups)

  • GET /lighting/state — list lights (name, state, location)
  • PUT /lighting/ — set single light state (body: { name, state })
  • PUT /lighting/outside — set all outside lights (body: { enabled: true/false })
  • PUT /lighting/inside — set all inside lights (body: { enabled: true/false })

• Servo (blinds/gates)

  • GET /servo/state — list servos (name, address, state)
  • PUT /servo/ — set servo state (body: { name, address, state })

Note: Some endpoints interact with physical devices — calls to device modules will have side effects on GPIO/I2C.

Wiring & Photos

Development notes & assumptions

• If anything in the actual hardware wiring or configuration differs from the assumptions in the code, prefer the real wiring/PCB and update the device modules accordingly.

Inferred Database Schema

See schema.sql for the CREATE TABLE statements inferred from the code. Create the schema before starting the app.