Smart Home Server

PV191 Smart Home Server is a simple server application that measures temperature, humidity, and VOC index. The measured data is displayed using an OLED display. The user can access a WEB UI for more thorough data analysis that is available after she has authenticated using a username and password.

Temperature and Humidity

SHT40 is a capacitive-type humidity and temperature sensor. It measures the relative humidity in the range of 0 - 100 %RH with a precision of ±1% and temperature in the range of -40 °C - 125 °C with a precision < ±0.1 °C.

Volatile Organic Compounds (VOC)

The setup utilizes Adafruit SGP40 Air Quality Sensor. The sensor uses the aforementioned temperature and humidity sensor to provide data for the computation of compensated VOC index. The index is computed using Sensirion VOC algorithm. The algorithm outputs a natural number in the range [0, 500 signalizing indoor air quality. Values below 100 indicate a typical indoor gas composition, while values above 100 indicate deteriorated air quality.

UI

WEB UI after authentication

Installation

Database

A database is necessary for measurement storage. Please, run a Postgresql DB before installing the server application, for example using Docker:

docker run --name pv191-server-postgres --user postgres -e POSTGRES_PASSWORD=mysecretpassword -d -p 5432:5432 --restart always postgres

After the DB server is running, and you've created a database for the application, specify the connection URL in the server unit file (You have to do this step after you've installed the server).

Server Installation

The server application is provided as a Debian package. The server runs as a systemd service upon installation.

wget https://github.com/KristianMika/pv191-smart-home-server/releases/download/v0.1.0/smart-home-server_0.1.0_arm64.deb
sudo apt-get install ./smart-home-server_0.1.0_arm64.deb

Nginx Reverse Proxy

To set up a reverse Nginx proxy, follow the official installation guide or use the official Nginx Docker image. The configuration file is provided in ./nginx.conf. Please, note you'll have to generate keys and certificates specified in the configuration file.

Nginx is necessary even if you are not planning on exposing the service to the Internet, as the proxy is used to wrap the traffic in https. Some features, such as notifications, require the https protocol.

Firewall

In case you are exposing the service to the Internet, consider installing a firewall.

Architecture

The application consists of 2 services:

1. The sensor-controller service samples sensors in user-specified intervals and stores measurements in the database
2. The server service serves the UI page and exposes API that, after the user has authenticated, provides measurements from the DB.

Architecture diagram