DIY Projects Home automation, connected objects (IoT) and DIY projects based on Arduino, ESP8266, ESP32, mini PC (Raspberry Pi, Orange Pi) and 3D printing
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After introducing the Homie library in the two previous articles (well starting with Homie, programming principle), it is time to move on to a complete example of application. In this tutorial we will learn how to include a temperature probe in the home wizard Home Assistant developed based on an ESP8266 and a DHT22 probe. To realize this probe, we will use the code developed in the previous tutorial.
If you’re starting out with Homie or developing connected objects, you can start by reading these articles
- Start with the MQTT Mosquitto Broker on Raspberry Pi, Windows, MacOS and Linux
- Start with the Homie library (MQTT) for connected objects ESP8266
- First Homie project. A DHT22 probe
Contents
Equipment used
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Wemos D1 Mini |
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5/3A micro-usb power supply
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Shield DHT22 or DHT11 for Wemos D1 Mini
Probe connected on D4 Pin (GPIO2) |
Circuit
The circuit is a classic of its kind. If you use a shield DHT22 or DHT11 for Wemos d1 mini, the sensor is connected to the D4 (GPIO-2) of the ESP8266.
Arduino code of the Homie project
Create a new sketch from the Arduino IDE and paste the following code.
Modify the spindle on which the DHT22 is connected and then upload the code. You can change the frequency of sending measurements by changing the TEMPERATURE_INTERVAL variable.
Follow the instructions in the Homie introduction tutorial to configure the connection to the Wi-Fi network and the MQTT broker (Mosquitto for example).
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#include <Homie.h> #include <DHT.h> const int TEMPERATURE_INTERVAL = 300; unsigned long lastTemperatureSent = 0; const int PIN_DHT22 = D4; // Broche - Pin DHT22 DHT dht(PIN_DHT22, DHT22); HomieNode temperatureNode("temperature", "temperature"); HomieNode humidityNode("humidity", "humidity"); void loopHandler() { if (millis() - lastTemperatureSent >= TEMPERATURE_INTERVAL * 1000UL || lastTemperatureSent == 0) { float t = dht.readTemperature(); float h = dht.readHumidity(); // Affiche les mesures dans le journal - send values to the logger Homie.getLogger() << "Temperature: " << t << " °C | humidity: " << h << "%" << endl; if ( !isnan(t) ) { temperatureNode.setProperty("temperature").send(String(t)); temperatureNode.setProperty("json").send("{\"t\":" + String(t) + ",\"unit\":\"c\"}"); humidityNode.setProperty("humidity").send(String(h)); humidityNode.setProperty("json").send("{\"h\":" + String(t) + ",\"unit\":\"%\"}"); lastTemperatureSent = millis(); } lastTemperatureSent = millis(); } } void setup() { Serial.begin(115200); Serial << endl << endl; Homie_setFirmware("demo-dht22", "1.0.0"); Homie.setLoopFunction(loopHandler); Homie.setup(); } void loop() { Homie.loop(); } |
Check that everything works as expected
Once the Wi-Fi network and the MQTT broker have been configured, it is good to check that messages are being received from the ESP8266. To do this, simply open a Terminal and execute this command
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mosquitto_sub -h localhost -t "homie / #" -v |
If you have set up an authentication, complete and run this command
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mosquitto_sub -h localhost -t "homie / #" -v -u "USER" -P "PASSWORD" |
Including a Homie IoT in Home Assistant
Now that everything is ready, we can include the Homie object in Home Assistant.
Configuring the connection to the MQTT broker
Move to the Home Assistant directory. If Home Assistant is running in a virtual python environment (recommended since December 2016), it is probably located there
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cd /home/homeassistant/.homeassistant |
Then open the configuration file
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sudo nano configuration.yaml |
Add a mqtt section and adapt the connection settings to your configuration
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mqtt: broker: localhost #si le Broker est installé sur le même poste qu'Home-Assistant port: 1883 #par défaut client_id: home-assistant-1 #peu important keepalive: 60 username: USERNAME #si l'authentification est active password: PASSWORD #idem protocol: 3.1.1 #par défaut |
Enable Debugging
During debugging, you can retrieve MQTT messages directly from the Home Assistant event log. To do this, add this configuration to the logger block
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logger: default: error logs: homeassistant.components.mqtt: debug |
Configuration of sensors
This is not required, but it is preferable to separate the configuration parameters in separate files. If you do not yet have a configuration file for the sensors, add the following parameter
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sensor: !include sensors.yaml |
Save the file (CTRL + X then O or Y)
Open the sensor configuration file sensors.yaml
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sudo nano sensors.yaml |
Paste the following configuration. Modify the Topics to match your Homie messages. It will be necessary to move the platform yr otherwise you will get a beautiful error that will prevent HASS from launching.
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- platform: yr # temperature Topic - platform: mqtt state_topic: homie/demohomie-projetsdiy/temperature/temperature name: "Homie DHT22" qos: 0 unit_of_measurement: "°C" # humidity Topic sensor dht_hum: platform: mqtt state_topic: homie/demohomie-projetsdiy/humidity/humidity name: "Homie DH22" qos: 0 unit_of_measurement: "%" |
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# temperature Topic sensor dht_temp: platform: mqtt state_topic: homie/demohomie-projetsdiy/temperature/temperature name: "Homie Tempertaure" unit_of_measurement: "°C" value_template: "{{ value | round(1) }}" # humidity Topic sensor dht_hum: platform: mqtt state_topic: homie/demohomie-projetsdiy/humidity/humidity name: "Homie Humidity" unit_of_measurement: "%" value_template: "{{ value | round(0) }}" |
- name: it is used to define the label that will be displayed on the screen. It will be used to integrate the sensor in a group or a view by replacing the spaces with the character _
- unit_of_measurement: the unit of measure that will be displayed
- value_template: value formatting mask. Here we make a rounding. For example, a significant number for temperature and none for moisture
Add measurements to groups
All we have to do now is to include the sensors in the groups. Here I have already prepared groups from previous tutorials on MySensors, RFLink and Xiaomi Mi Home Aquara. To add a sensor, use the usual formality sensor.sensor_name. The name is obtained by replacing the spaces with the symbol “_”. Which give
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temperature: name: Sondes de température entities: - sensor.homie_temperature humidity: name: Sondes d'humidité entities: - sensor.homie_humidity |
Save all configuration files (CTRL + O or CTRL + X then O) and then restart the Home Assistant service
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sudo systemctl restart home-assistant@homeassistant |
Or with this command if Home Assistant is not installed in a Python virtual environment
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sudo systemctl restart home-assistant |
To monitor that everything is properly configured, run the following command to track the Home Assistant runtime log
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sudo journalctl -fu home-assistant@homeassistant |
And then, after a few moments, you will receive the first MQTT messages from the ESP8266.
And here is the display
It is really easy to integrate connected objects developed with the Arduino Homie library. Homie is a very powerful library that has been thought for home automation. It supports very well the relay commands but also the dimmers very used in Led lights.
- Include ESP8266 + DHT22 + Homie MQTT IoT in Home Assistant (HASS)
- How to include MySensors v2 IoT objects in Home Assistant (HASS)
- Installing and Including the Xiaomi Smart Home Kit on Home Assistant (HASS)
- Soma Smart Shades, Wazombi Labs Solar Connected Curtain Motorization
- Install Home Assistant (HASS) on an Orange Pi running under Armbian
