ESPHome and Home Assistant Beginner Guide: Build Your First WiFi Sensor

ESPHome turns an ESP32 into a smart home sensor or controller with almost no code. Combined with Home Assistant, it is the most powerful DIY home automation setup available.

What You Will Build

A WiFi temperature and humidity sensor that reports every 30 seconds to Home Assistant, appears automatically in your dashboard, and survives reboots. Total hardware cost: under $10.

Hardware Needed

ESP32 DevKit (~$5)
BME280 temperature/humidity/pressure sensor (~$4) — recommended over DHT22 for accuracy
USB cable, jumper wires

Wire the BME280 (I2C)

BME280 PinESP32 Pin VCC3.3V GNDGND SDAGPIO 21 SCLGPIO 22

Install ESPHome

In Home Assistant: Settings → Add-ons → Add-on Store → search ESPHome → Install → Start.

Create Your Device

ESPHome dashboard → New Device → name it → Edit. Paste this configuration:

esphome: name: workshop-sensor friendly_name: Workshop Sensor esp32: board: esp32dev logger: api: encryption: key: !secret api_key ota: password: !secret ota_password wifi: ssid: !secret wifi_ssid password: !secret wifi_password ap: ssid: "Fallback Hotspot" password: "fallback123" i2c: sda: GPIO21 scl: GPIO22 sensor: - platform: bme280_i2c temperature: name: "Temperature" pressure: name: "Pressure" humidity: name: "Humidity" address: 0x76 update_interval: 30s

Flash Your ESP32

ESPHome dashboard → Install → Plug into this computer → select USB port → Install.

First flash takes 2–3 minutes to compile. Future updates are wireless (OTA).

Connect to Home Assistant

HA will auto-discover the device. Settings → Devices & Services → Configure. Your sensors are now available for automations and dashboards.

What to Build Next

ESPHome supports nearly any hardware with simple YAML additions:

Motion sensor (PIR) — trigger automations on presence
Door/window sensor (reed switch) — detect open/close
RGB LED controller — control strips from HA
Smart relay switch — control lights or appliances
CO2 monitor (MH-Z19B) — air quality
Water leak detector — under-sink protection
Energy monitor (PZEM-004T) — whole-home power monitoring

Each takes 10–30 lines of YAML and works exactly like the temperature sensor.

ESPHome vs Tasmota

Both flash open-source firmware to ESP devices. ESPHome is YAML-configured and tightly integrated with Home Assistant. Tasmota works with more platforms but is more complex. If you use HA, ESPHome wins.

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