NodeMCU Lua Code for Home Automation

This repository contains code, firmware, and helper scripts for programming a NodeMCU ESP8266 chip (specifically this one).

Firmware

The included firmware was built with the NodeMCU cloud build service to include a few extra modules (MQTT, HTTP, and others I can't remember).

Scripts

There are a few helper scripts in the bin directory for connecting to the ESP8266 and uploading firmware/code. You will need Python 2 installed for them to work. If necessary, a virtual environment will be created and the necessary software installed.

Serial Connection

With your ESP8266 connected, run:

bin/connect-serial.sh

to start a serial terminal session. This assumes the ESP8266 is connected on /dev/ttyUSB0. Press CTRL + ] to exit.

Upload Firmware

To upload the included firmware (in the firmware directory), just run:

bin/upload-firmware.sh

Upload Code

Once you have the ESP8266 programmed, you can upload all of the .lua files in a directory with:

bin/upload-code.sh <DIR>

where <DIR> is the directory containing init.lua, etc.

Lua Code

The included code under src is for two different use cases:

1. A magnetic door sensor (reed switch)
2. A gyro washer/dryer sensor (MPU6050)

Both projects uses the same init.lua script that automatically gets executed at boot. This script reads a secrets.lua file (not included), which contains the WiFi SSID and password to connect to. After a brief delay, it automatically connects to WiFi and runs application.lua, which contains project-specific code.

The init.lua script also supports downloading the application.lua code from an HTTP server, allowing for "over the air" updates (with a reboot). If you define CODE_HOST in secrets.lua, the ESP8266 will download http://CODE_HOST/nodemcu/<chipid>/application.lua on boot (where <chipid> is from node.chipid()).

Helper Functions

There are some shared helper functions defined in:

• mqtt.lua
  • Keeps an MQTT connection alive by pinging itself every second
• led.lua
  • Turn the built-in blue and red LEDs on and off

Door Sensor

Reads the state of a magnetic (reed) switch on GPIO5 (open high) and reports it via MQTT. The switch state is both polled every second and caught via interrupt.

The result is used by a Home Assistant binary sensor.

Excerpt from configuration.yaml:

binary_sensor:
  - platform: mqtt
    name: "Back Door Sensor"
    state_topic: "home-assistant/back-door"
    value_template: >
      {% if value != "closed" %}
      ON
      {% else %}
      OFF
      {% endif %}

Washer/Dryer Sensor

Reads the gyro state of the MPU6050 every second and publishes it out as JSON via MQTT.

The results are tracked by a Home Assistant filter sensor to create a moving average. This (thresholded) value is then used by a Home Assistant binary sensor to determine whether the washer/dryer is on or off (mine are next to each other).

Excerpt from configuration.yaml:

sensor:
  - platform: mqtt
    name: laundry_motion_raw
    state_topic: "home-assistant/laundry"
    value_template: "{{ value_json.gyro }}"
  - platform: filter
    name: laundry_motion
    entity_id: sensor.laundry_motion_raw
    filters:
      - filter: time_simple_moving_average
        window_size: 00:05
        precision: 2
        
binary_sensor:
  - platform: threshold
    name: "Laundry Sensor"
    entity_id: sensor.laundry_motion
    upper: 5.0