DHT22 to Grafana (Graphite)

A small Rust service for Raspberry Pi that reads data from a connected DHT22 sensor and posts it to a Graphite instance (on Grafana Cloud for example).

Pre-requisites

• Raspberry Pi
• DHT22
• Grafana Cloud or a self-hosted Graphite instance

Installation - compiling from source

On your Raspberry Pi:

1. Clone the repo gh repo clone keturiosakys/raspberry-temperature-monitoring
2. cd into it
3. Run cargo build --release
4. Grab the compiled binary from the target/ directory

Cross-compiling

Due to long Rust compilation times I would recommend cross-compiling the code on your main machine and porting over the compiled binary to the Raspberry Pi.

Use cargo-zigbuild (which uses the zig linker) or cross (which uses Docker to provide the toolchain) to compile for your Raspberry Pi CPU architecture with minimal setup.

How it works

rpi-monitoring compiles to a monitoring binary that runs as any CLI application. Under the hood it uses the simple but reliable dht22_pi crate to read the actual sensor.

You can run monitoring check --pin <GPIO_PIN> to sample data from your connected DHT22 sensor and verify that it's working.

The monitoring serve is the command that can run in the background sampling and posting the temperature data to your Graphite instance.

It requires a Graphite endpoint and a Grafana API key passed in as flags as well as a sensors.yaml file to be available in the same directory.

sensors.yaml file lists and labels all the connected DHT22 sensors.

- name: kitchen # label, must be all lowercase, no spaces
  pin: 4 # GPIO pin it's connected to

You can set up the executable as a systemd service - there's an example monitoring.service in the repository!

Please post any questions or report any issues in the Github Issues of this repo.