ESP32 + ESPHome temperature sensor for Home Assistant (condensed)

Also available in French.

A DIY ESP32 temperature sensor with ESPHome shows up automatically in Home Assistant—good when you want USB power and full control. This is a short path; for deep troubleshooting, enclosures and battery builds, see the full ESPHome getting started with Home Assistant and our ESP32 project ideas.

Board choice: which ESP32 for smart home.

Parts

Item	Notes
ESP32 dev board	Classic ESP32 or ESP32-C6 DevKit—search UK · US
DHT22	Simple 1-wire, ±0.5 °C typical—UK · US
BME280 (optional)	I2C, humidity + pressure—UK · US
Breadboard + dupont wires	Prototype before enclosure

Use 2.4 GHz Wi-Fi only (ESP32 does not join 5 GHz).

1. Install ESPHome in Home Assistant

Settings → Add-ons → ESPHome → Install → Start → Show in sidebar. Docs: ESPHome on Home Assistant.

2. Wire DHT22 (example)

DHT22          ESP32
VCC    →       3.3V
DATA   →       GPIO4
GND    →       GND

Optional 4.7 kΩ from DATA to 3.3V if reads are unstable on long wires.

BME280 (I2C): VCC/GND to 3.3V/GND; SDA/SCL to board defaults (often GPIO21/22 on classic ESP32, GPIO6/7 on some C6 boards—check your pinout).

3. Create and flash

ESPHome → New device → name living-room-sensor → pick chip type.
Enter Wi-Fi SSID/password (2.4 GHz).
Install → Plug into this computer (first time USB); hold BOOT if flash fails.
Device appears under Settings → ESPHome.

4. Minimal YAML (DHT22)

Edit the device and add or merge:

sensor:
  - platform: dht
    pin: GPIO4
    model: DHT22
    temperature:
      name: "Living Room Temperature"
    humidity:
      name: "Living Room Humidity"
    update_interval: 60s

BME280: use bme280_i2c with i2c: block—see ESPHome BME280.

Install wirelessly (OTA) after the first USB flash.

5. Use in Home Assistant

Entities appear as sensor.living_room_temperature etc. Add to dashboard; automate heating with a Zigbee plug (temperature sensors compared).

Example: turn on radiator plug when below 19 °C between 06:00–22:00—same pattern as Zigbee sensors in our getting started path.

Quick fixes

Wi-Fi fails: wrong band (5 GHz), guest isolation, or charge-only USB cable.
DHT22 NaN: wiring, GPIO pin, or update_interval under 2 s.
Readings high: sensor too close to the ESP32—extend with 20–30 cm wires; optional offset filter in YAML.

Prefer no soldering and battery life? Use Zigbee temperature sensors instead.

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