As the weather gets colder, having accurate temperature and humidity readings in your home becomes increasingly important for comfort and safety. In this blog post, we will walk through the process of setting up a system of temperature and humidity sensors running on ESP8266 SoCs using the open-source software ESPHome, Home Assistant, and MQTT. This is a project I've been focused a lot on lately. I have sensors in nearly every room and even inside my Heat Recovery Ventilator. I can track how much heat I'm recovering when removing 'stale' air from within. Let me know of any questions!
First, you will need to gather the necessary hardware. For this project, you will need one or more ESP8266-based development boards, such as the D1 Mini, a DHT22 temperature and humidity sensor, and a 5v USB power supply. You will also need a computer or a Raspberry Pi to run Home Assistant and MQTT. I'm not going to discuss how to set up these in this post, in the future I want to break down my setup. I currently run HAOS on Proxmox. The ESP and DHT can be found for a few dollars on AliExpress, or if you're impatient you can get them from Adafruit or similar I'm sure. I don't affiliate, so no links.
The first step is to flash the ESP8266 development boards with the ESPHome firmware. ESPHome is a custom firmware for ESP8266 and ESP32 boards that allows for easy integration with Home Assistant. You can flash the firmware using the ESPHome wizard, which guides you through the process step by step.
Next, you will need to connect the DHT22 temperature and humidity sensor to the D1 Mini board. The sensor uses a single pin for data communication and requires a pull-up resistor of about 10kΩ. I selected D5.
With the sensor connected, you can now configure the ESPHome firmware on your D1 Mini board. Here is the sample ESPHome code you need to include in your configuration file:
- platform: dht
name: "Temperature Sensor"
name: "Humidity Sensor"
In this code snippet, the platform is set to dht, pin is set to D5 (the pin the sensor is connected to) and we are giving custom name to sensors (Temperature Sensor and Humidity Sensor). Obviously place the name of the room you're sensing.
Once your ESP8266 board is configured, you can connect it to your Home Assistant installation. Home Assistant is an open-source home automation platform that can integrate with a variety of devices and services. To integrate your ESP8266 sensors, you will need to add a new sensor to your Home Assistant configuration file and specify the IP address and port of your MQTT server. Again not in this post. This is a general guide I created upon doing this myself.
At this point, you should have a working system of temperature and humidity sensors running on ESP8266 SoCs, integrated with ESPHome, Home Assistant, and MQTT. You can now use Home Assistant to view sensor readings and set up automations based on temperature and humidity levels.
This project is a great way to take control of your home's environment and make your home more comfortable and energy-efficient. Even just tracking the data within Home Assistant and passing that into InfluxDB is pretty nice. Having the data at a fingers reach is great, flashing cheap ESP8266 with ESPHome is going to be another topic.