Firmware for Raspberry Pi sensors used in Lafayette Engagement and Research Network air quality sensor network.

Uses a simple and flexible YAML-based configuration to give each sensor its own personality, regardless of the sensors installed. This configuration file is used to enable the drivers specific to each kind of supported sensor (e.g. Alphasense OPN-N2, Aeroqual SM50), and to enable one or more network transports (e.g. SensorThings over HTTPS, Azure IoT Hub, etc.). See below for an example configuration file.

Example configuration

simulator:
  enabled: true
logging:
  logger_path: /var/log/sensor.log
  level_console: INFO
  level_file: DEBUG
spooler:
  db_path: /var/spool/mqueue/sensor.sqlite
thing:
  id: 5474a427-f565-4233-8f82-a8178534b150
  location_id: f5610fb9-1556-42d8-862c-1d290a9b5c58
sensors:
  - type: mq131
    observed_properties:
      - name: ozone
        datastream_id: 1af6b695-07c0-4024-aeb8-4ddf64dbf458
  - type: dht11
    multidatastream_id: 1874209f-72b0-4d7f-993c-2707fa01ccd2
    observed_properties:
      - air_temperature
      - relative_humidity
transports:
  - type: https
    properties:
      auth_url: https://myservice.com/auth
      url: https://myservice.com/v1.0/
      jwt_id: 6d770f60-9912-4545-9d3c-9e8dcf4a0dad
      jwt_key: faac9ce4-fd2d-476b-9984-aee2b71dfc8e
      jwt_token_ttl_minutes: 15
      transmit_interval_seconds: 15
      verify_ssl: false

Architecture

The sensor firmware uses a de-coupled/distributed architecture to ensure reliable: sensing, data storage, and data transmission. This architecture is summarized in the image below.