airmeter

README

Air Meter

airmeter reads the temperature, pressure and humidity from sensor and publishes those readings as JSON to an MQTT endpoint.

I expect the JSON format will change over time, but currently the readings are published to <<topicroot>>/<<location>> with the format:

{
  "Temperature":15.978877,
  "Humidity":38.132843,
  "Pressure":101718.31
}

If the sensor doesn't support a value, it should not be included in the output.

Architecture

The current goal is to simply track the data for a few locations around my home. The architecture plan is to have multiple sensors that publish to an MQTT broker and use telegraf to pull that data and insert it into an instance of influxdb.

Hardware

The supported/tested sensors are:

• Dummy (returns a random temperature, humidity, and pressure)
• Adafruit BME280 sensors
• Adafruit SHT31-D sensors

and their relatives, wired to the i2c bus of a Pi Zero W.

Usage

  Usage of airmeter:
  -V display version information and exit
  -a string HTTP listen address (default ":8000")
  -b string MQTT broker endpoint (default "tcp://iot.eclipse.org:1883")
  -d string Which sensor driver to use: 'dummy', 'bme280' or 'sht3x' (default "bme280")
  -e string Static correction factor for the temperature.  ie. '5', '-3', '1.2 (default "0")
  -f string frequency to collect data from the sensor (default "5s")
  -l string location for the sensor (default "home")
  -r string Static correction factor for the pressure.  ie. '5', '-3', '1.2 (default "0")
  -s Advanced: start a subscription on the MQTT topic and print to STDOUT
  -t string Advanced: Set the MQTT topic root - the topic will be 'topicroot/location' -  (default "airmeter")
  -u string Static correction factor for the humidity.  ie. '5', '-3', '1.2' (default "0")
  -v enable verbose output

Development

Build for Pi Zero W

env GOOS=linux GOARCH=arm GOARM=5 go build

Backend

All backend components are simple docker containers running on a single 5 year old Intel NUC. Nothing fancy here....

Eclipse Mosquitto MQTT server

mosquitto

Telegraf

telegraf

Input

[[inputs.mqtt_consumer]]
  servers = ["tcp://mosquitto-server:1883"]
  topics = [
    "airmeter/office"
  ],
  data_format = "json"

Output

[[outputs.influxdb]]
  urls = ["http://influxdb:8086"]
  database = "airmeter"

InfluxDB

influxdb

Grafana

grafana