Raspberry Pi Temperature Monitor

This project provides code to read temperature sensors and to display them in a neat and customizable web interface. With this we can check our hybrid heating system (wood and oil) from everywhere and easily see if we need to put more wood on the fire.

Requirements

• RaspberryPi, in my case with hostname heizung
• Installed webserver, I used nginx
• A few DS18B20 sensors
• A free weekend

Project Structure

There are two folders in the project:

• ui: the react based website
• backend: scripts to read temperatur data

UI (website)

A react based UI shows the temperature sensors for my heating system. There are two buffers on the left and some other sensors for the two kettles and some pipes on the right. They are color coded to instantly see if some temperatures are too high or too low.

Backend

The backend is based on this awesome guide by Stefan Truppel: https://st-page.de/2018/01/20/tutorial-raspberry-pi-temperaturmessung-mit-ds18b20/

The script was modified to iterate over a set of sensors and prints a summary into the file /var/www/html/sensors.json. This is then used for the website.

Installation

Getting Sensor Data

Modify get_sensor.py, replace my sensors' IDs with yours. As soon as you properly attached the sensors, you can find your sensors' IDs in folder /sys/bus/w1/devices/. You can define the sensors' IDs to whatever you like, you just have to make sure the webui takes the proper values later.

Run the script once with python3 get_sensor.py. Once the script is started, it constantly checks for temperatures.

Create a Service

Using get_sensor.py you can create a service. Create the file /etc/systemd/system/rpiheating.service with this content:

[Unit]
Description=Pi Heating monitoring
After=network.target
StartLimitIntervalSec=0
[Service]
Type=simple
Restart=always
RestartSec=1
User=pi
ExecStart=/usr/bin/python /home/pi/rpiheating/backend/get_sensor.py

[Install]
WantedBy=multi-user.target

Start and enable the service with this:

systemctl start rpiheating
systemctl enable rpiheating

Building the Webapp

First of all, install node.js, e.g., via apt install nodejs and give it a try.

npm install
npm audit fix
npm start

Build the optimized app with:

cd ui
npm run build
npm intall -g serve # only once

Copy the optimized build from build/* to /var/www/html. Browse to http://heizung.

Important: If you changed the sensor IDs in the get_sensor.py, you have to modify them in the UI as well.

Open Topics

• Put values into a database
• Implement statistics page