Chapter 5 · ESP32 Sensors5 min

BMP280 Pressure

Wire a BMP280 over I²C and display pressure on an LVGL bar.

The pattern - same for any I²C sensor

I²C bus reads chip

update_interval: 30s

on_value

fires with new reading

lvgl.label.update

push to widget

I²C is a shared bus - you can add BMP280, SHT3x, OLED, and more on the same two wires.

Design labels for temp + pressure

Two labels: one for temperature (temp_lbl), one for pressure (press_lbl).

Designer with temperature and pressure labels

yamlYour labels (from the designer)

# Your LVGL widgets (from the designer)

lvgl:
  pages:
    - id: canvas_3
      bg_color: 0xFFFFFF
      pad_all: 0
      widgets:
        - label:
            id: temp_lbl
            x: -40
            y: -55
            align: CENTER
            text: "--.- °C"
            text_color: 0x000000
            text_font: montserrat_28

        - label:
            id: press_lbl
            x: -20
            y: 10
            align: CENTER
            text: "---- h"
            text_color: 0x000000
            text_font: montserrat_28

Wire the BMP280

Four wires. SDA and SCL are the I²C bus - they're shared, so you can daisy-chain other I²C sensors on the same pins.

BMP280ESP32Notes

VCC3.3V3.3V only - no 5V!

GNDGND

SDAGPIO27I²C data (shared bus)

SCLGPIO22I²C clock (shared bus)

BMP280 sensor board with four wires connected to an ESP32 development board

If your display's touch chip is also on I²C, check the address doesn't clash. Most touch controllers sit at 0x14/0x38/0x5D - no conflict with BMP280's 0x76/0x77.

Add the sensor YAML

yamlI²C bus + BMP280 → labels

# Add at root level of your device YAML

i2c:
  sda: GPIO27
  scl: GPIO22
  scan: true   # logs detected addresses on boot

sensor:
  - platform: bmp280_i2c
    address: 0x76    # try 0x77 if 0x76 doesn't respond
    update_interval: 30s
    temperature:
      id: bmp_temp
      name: "Outside temperature"
      on_value:
        then:
          - lvgl.label.update:
              id: temp_lbl
              text: !lambda |-
                return str_sprintf("%.1f °C", x).c_str();
    pressure:
      id: bmp_press
      name: "Outside pressure"
      on_value:
        then:
          - lvgl.label.update:
              id: press_lbl
              text: !lambda |-
                return str_sprintf("%.0f hPa", x).c_str();

i2c:Initializes the I²C bus - only needed once even with multiple I²C sensors

scan: trueLogs all detected I²C addresses on boot - remove after confirming

address: 0x76Most BMP280 boards. Try 0x77 if 0x76 doesn't respond

First boot trick: set scan: true and check the boot log. ESPHome will print every I²C address it finds - you'll see your BMP280 and any other I²C devices.

Flash and watch

ESPHome display showing temperature and pressure readings from the BMP280 sensor

[I][i2c]: Found device at 0x76

[D][bmp280]: Got temp=23.1°C

[D][bmp280]: Got press=1013.2hPa

[D][lvgl]: temp_lbl → "23.1 °C"

[D][lvgl]: press_lbl → "1013 hPa"

Checkpoint - Do the boot logs show BMP280 detected, and do the labels update?

If yes - you have a working I²C sensor. Add BME280, SHT3x, or any other I²C device the same way on the same bus.

Yes - keep going Sensor not found / I²C scan empty