DHT Monitor

Web interface to check the current and past temperature and humidity values read from a DHT22 sensor on a Raspberry Pi.

Usage

Run the application

Run ./bootstrap.sh to

• start collecting data in the configured sqlite database file
• start a flask web server on port 5000
• build the react application and copy it to /var/www/dht-monitor to be served by a web server
  • /var/www/dht-monitor will be removed before copying new files

Configuration

A configuration file is required and can either be specified as the bootstrap script's first argument or put at the default location ~/.dht-monitor.yaml

Example:

sqlite:
  file: /home/pi/dht/dht_values.db
  cleanup: # optional section to remove old values from the database
    enabled: true # default: false
    # maximum age of entries to be kept in the database
    # the following config would clean up all entries dating back more than 36.5 hours (1d + 12h + 30m)
    delta:
      days: 1     # adds days to the time delta, default: 0
      hours: 12   # adds hours to the time delta, default: 0
      minutes: 30 # adds minutes to the time delta, default: 0
sensor:
  datapin: D2 # PIN to poll data from, must be a valid board value
  interval: # intervals at which sensor is polled in seconds, optional section
    success: 15.0 # timeout after successful poll, default: 10.0
    fail: 3.0     # timeout after failed poll, default: 2.0

Usable API endpoints

• localhost:5000/dht/data endpoint returns collected temperature and humidity data
  • can be limited with h/m/s query parameters to the last X amount of time (e.g. "/data?m=3&s=30")
  • by default data collected in the last 15 minutes is returned
• localhost:5000/dht/current offers a WebSocket connection to receive the latest data

Wiring

Connect the DHT22 sensor's data output to the GPIO PIN specified in sensor.datapin (see "Configuration").

Dependencies

Libraries and build tools which are not automatically installed by pipenv or yarn and must be installed before the software can be used.

Libraries

• libgpiod2 (sudo apt-get install libgpiod2)

Build tools

• pipenv (sudo apt-get install pipenv)
• yarn

Web server

A web server like Apache or nginx to serve the react frontend from /var/www/dht-monitor

Attribution

Favicons

The favicon graphics were created by Twemoji (https://twemoji.twitter.com/) and are licensed under CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)