Air Quality Sensor API Server for Raspberry Pi

Over the Air Air Meters.

Development

Prerequisites

install rustup and cargo to use the rustlang platform

Dev Frontend

The frontend is compiled statically from a nextjs app. During development you can run the nextjs development server for hotreloading. localhost:3000 is allowed through the API server's Cors setup for development.

npm run dev

By default the API server has a html template that loads the frontend javascript when available. You will need to build and pack the frontend to get interactivity in the site when accessing the site from the API server which is covered in Prod Frontend below. this will need to done before cross_deploy.

Run Server

During development the sensor data will be placeholder values derived from unix time.

cargo run

Compiling on arm architecture will activate the production sensor code

Cross compilation

Prerequisites

install cross (requires docker)

cargo install cross

Process

inside cross_deploy.sh replace value of TARGET_HOST with ssh address of your device. Make sure the target and source paths are valid too.

Then run cross_deploy.sh to compile, scp the server binary, and run it over ssh.

Prod Frontend

Keep in mind you will need to build the frontend app.

Prerequisites

install npx, node and npm

Process

run the pack_site.sh script or follow its commands - whatever works for you

TODO

sensor client

• sensor obtains publisher authorization id
• set authorization header to id - connect to webserver websocket
• on loop send sensor data and detect wether to reinitialise ccs811 assign to context property
• seperate thread that can delete and reinitialise sensor thread context property based on http GET request

web server

• on startup start sensor thread
• setup actix server
• receive air_meter_node requests via websockets
  • note - provision for db based config response for node (increment, restart)
• support websocket requests for air_meter
• save air_meter readings to db accessable by users
• serve web_client requests with Askama template
• serve web_client with template that requests react_app
• add to system startup (singleton)
• adjustable reading increment
• visually indicate sensor warmup based on sensor uptime
• change heartbeat to ~30 minutes - then indicate sensor client may have crashed based no heartbeat from client after 5 minutes

wifi hotspot config network (Captive Portal)

• in factory config rasp pi starts with wifi hotspot with webpage for config
  • user joins rasp pi wifi - navigates to config webpage
  • enter wifi password - rasp pi will have to terminate hotspot then test wifi password
  • sensor client obtains authorization id and server address?
  • use websockets to notify of success with ip of rasp pi on user's wifi (user will have to join orig wifi manually)

Captive Portal mode for sensor operation webapp

• user can choose to access sensor app through captive portal instead of through existing local network
  • mode can be chosen at config network or at sensor app
  • https://raspberrypi.stackexchange.com/a/100118

Battery Power

• Display Battery levels and estimated lifetime for battery powered device
• save energy https://core-electronics.com.au/tutorials/disable-features-raspberry-pi.html