This code shows how to create a simple Wi-Fi module with a light, temperature and movement sensor using an ESP8266 module. It uses mqtt to send these readings to a central location.
- ESP-12 (or another ESP8266 with 2 GPIO's and the ADC available) - €2.50
- A light-dependent resistor (LDR) - €0.10
- A PIR sensor - €1.00
- DS18B20 temperature sensor - €1.00
- 1kΩ + 4.7kΩ resistor - €0.10
TODO
You will need the NodeMCU firmware for this. The current master version does not have the mqtt sending queue implemented yet (it's only in the dev branch), so you can use the firmware in the /bin directory from this repository. Otherwise publishing to multiple topics at the same time will crash NodeMCU.
Once your ESP8266 is running NodeMCU upload all files from the /lua directory to it. Be sure to change ssid, password and mqtt connection settings in init.lua and mqtt.lua.
Information will be published to the following topics. The MAC address of the ESP is used as the identifier (actuator/mac address/value).
| topic | values | description |
|---|---|---|
| actuator/18-FE-00-01-02-03/state | ON - OFF | Device online, controlled by mqtt LWT |
| actuator/18-FE-00-01-02-03/movement | ON - OFF | Movement detected |
| actuator/18-FE-00-01-02-03/light | 0-100% | Light percentage |
| actuator/18-FE-00-01-02-03/temperature | °C | Temperature |
You probably want to use this sensor as part of a larger home automation system. openHAB is one of these. Check the documentation for the mqtt binding. The sensor readings can then be used like this:
Switch Movement_Living "Movement [%s]" {mqtt="<[home:actuator/18-FE-00-01-02-03/movement:state:default]"}
Number Light_Living "Light [%.0f%%]" {mttq="<[home:actuator/18-FE-00-01-02-03/light:state:default]"}
Number Temperature_Living "Temperature [%.1f °C]" {mqtt="<[home:actuator/18-FE-00-01-02-03/temperature:state:default]"}
Switch Sensor_Living "Sensor Living" {mqtt="<[home:actuator/18-FE-00-01-02-03/state:state:default]"}
Open an issue here or contact me @idserda.