Sensor API for the Raspberry Pi

The Sensor API for the Raspberry Pi is a web service that give access to environmental information of a Raspberry Pi. It uses the sensors of the Sense Hat as well as the internal CPU thermometer.

It returns the information as a JSON structure:

{
  "C": 50.464, 
  "H": 39.45915603637695, 
  "P": 941.78369140625, 
  "T": 34.720176696777344
}

• C is the CPU Temperature (in °C)
• H is the Humidity (in %rH)
• P is the Barometric Pressure (in Millibars)
• T is the Ambient Temperature (in °C)

Installation

Install the required software:

sudo apt update
sudo apt install sense-hat libatlas-base-dev libopenjp2-7-dev gunicorn3

Install the app:

sudo pip install heiafr-hydrocontest-sensor_api

Running

If you want to test the service you can just start it localy using gunicorn:

gunicorn3 heiafr.hydrocontest.sensor_api:app

You can now go to http://127.0.0.1:8000 and check the result.

In a production environment, you would rather start the service using systemd and use a reverse proxy (e.g. Nginx) in front of it.

You can use this systemd service file (you can name it heiafr-hydrocontest-sensor_api.service):

[Unit]
Description=HEIAFR Hydrocontest Sensor API
After=network.target

[Service]
User=root
Group=root
ExecStart=/usr/bin/gunicorn3 --bind=0.0.0.0:8081 heiafr.hydrocontest.sensor_api:app

[Install]
WantedBy=multi-user.target

This is a possible Nginx configuration:

location /sensors {
    proxy_set_header    Host $host;
    proxy_set_header    X-Real-IP $remote_addr;
    proxy_set_header    X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header    X-Forwarded-Proto $scheme;
    proxy_pass          http://localhost:8081/;
    proxy_read_timeout  90;
}