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diff --git a/README.md b/README.md new file mode 100644 index 0000000..7621b7c --- /dev/null +++ b/README.md @@ -0,0 +1,65 @@ +# CO₂ Monitor + +This repository contains NodeMCU Lua source code for an [MH-Z19 based CO₂ monitor](https://finalrewind.org/projects/co2-monitor-mhz19-ssd1306/). +It shows the current CO₂ concentration and MH-Z19 temperature on a 128×32 SSD1306 OLED and makes them available to Home Assistant via MQTT. +It can also publish readings to InfluxDB. + +## Features + +* Display for CO₂ and temperature +* Home Assistant integration via MQTT +* Optional logging to InfluxDB +* Powered via USB + +## Components + +* Processor: ESP8266 +* CO₂ sensor: MH-Z19 +* Display: 128×32 OLED via SSD1306 (128×64 also supported with some changes) + +## Configuration + +WiFi, Home Assistant, and InfluxDB configuration is read from `src/config.lua`. +You will need the following entries. + +### WiFi + +Assuming ESSID "foo" and PSK "bar". +WPA2 Enterprise is not supported. +Leave out the `psk` for open WiFi. + +```lua +station_cfg = {ssid = "foo", pwd = "bar"} +``` + +### MQTT + +The only configurable entity is the hostname of the MQTT broker. The ESP8266 +will register itself as `homeassistant/sensor/esp8266_XXXXXX` with the last six +digits representing its WiFi MAC address. + +```lua +mqtt_host = "mqtt.example.org" +``` + +### InfluxDB + +These settings are optional. Specify a URL and attributes in order to enable +InfluxDB publishing. For instance, if measurements should be stored as +`mh_z19,location=lounge` in the `sensors` database on +`https://influxdb.example.org`, the configuration is as follows. + +```lua +influx_url = 'https://influxdb.example.org/write?db=sensors' +influx_attr = ',location=lounge' +``` + +You can also use the `esp8266_XXXXXX` device id here, like so: + +```lua +influx_url = 'https://influxdb.example.org/write?db=sensors' +influx_attr = ',location=' .. device_id +``` + +Optionally, you can set `influx_header` to an HTTP header that is passed as +part of the POST request to InfluxDB. |