ESPHome provides built-in support for the BME680 sensor with a fully open-source implementation; however, it is not compatible with all the sensor’s features. The project also includes Bosch’s proprietary BSEC v1 and v2 software libraries that support different ESP boards. Learn how to set up and configure your sensors in this post with examples for the ESP32 S2 and C3 boards.

The BSEC is a proprietary library by Bosch that offers Index for Air Quality (IAQ) measurement derived from the gas resistance sensor’s response to specific Volatile Organic Compounds (VOC). It also estimates values for CO₂ and Breath Volatile Organic Compounds (b-VOC) using the correlation between VOC and CO₂ in human exhaled breath.

While both BSEC versions deliver the same functionality, only v2 includes binaries for the ESP32-S2 and ESP32-C3. Based on the information provided here and here I managed to compile list of CPU support for each version of the library:

Platform	Compiler	Library	CPU / TYPE
ESP8266	xtensa-lx106-elf-gcc	v1 | v2	ESP8266
ESP32	xtensa-esp32-elf-gcc	v1 | v2	ESP32
ESP32-S2	xtensa-esp32s2-elf-gcc	v2	ESP32-S2
ESP32-S3	xtensa-esp32s3-elf-gcc	v2	ESP32-S3
ESP32-C3	riscv32-esp-elf-gcc	v2	ESP32-C3
Cortex-ARM	ARMCC	v1	Cortex-M0, M0+, M3, M4, M4_FPU, M7
Cortex-ARM	GCC	v1 | v2	Cortex-M0, M0+, M3, M4, M4_FPU, M7, M33, M33_FPU
Cortex-ARM	IAR	v1	Cortex-M0, M0+, M3, M4, M4_FPU, M7
Cortex-A*	GCC	v1	Cortex-A7
AVR_8bit	AVR-GCC	v1	MegaAVR, XMEGA
AVR_32bit	AVR-GCC	v1	32-bit AVR UC3
MSP430	msp430-elf-gcc	v1	MSP430
Android system-x86	gcc	v1	x86, x86_64
Android system-arm	gcc	v1	arm, arm64
Raspberry PI 0 linux	arm-linux-gnueabihf-gcc	v1	armv6-32bits
Raspberry PI3 linux	arm-linux-gnueabihf-gcc	v1	armv8-a-64bits

BSEC Version: Which One to Pick?

• https://esphome.io/components/sensor/bme680_bsec.html
• https://esphome.io/components/sensor/bme68x_bsec2.html

The project recommends using the newer bme68x_bsec2 component whenever possible. In my experience BSEC v2 provides considerable more accurate readings, so if you board supports it just go for it.

Now I’ll share full configuration examples for the ESP32 S2 and ESP32 C3 boards, you should then be able to replicate this with all the other boards supported by the v2.

ESP32 S2 Mini Board

This board is also konw as lolin_s2_mini.
Board documentation available at: https://www.wemos.cc/en/latest/s2/s2_mini.html

esphome:
  name: "demo-esp32-s2"
  friendly_name: demo-esp32-s2

external_components:
  - source: github://TCB13/esphome@bsec2_bme68x
    components:
      - bme68x_bsec
    refresh: 0s

esp32:
  board: lolin_s2_mini
  variant: ESP32S2
  framework:
    type: arduino

# Enable logging
logger:
  level: ERROR

api:
  encryption:
    key: "YYYYYYYYYYYYYYYYY"

ota:
  - platform: esphome
    password: "XXXXXXXXXXXXXXX"

safe_mode:
  disabled: true

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  #ap:
  #  ssid: "Esphome-Web-aaaaaaaaa"
  #  password: "xxxxxxxxxxxx"

#captive_portal:

#web_server:
#  port: 80
#  version: 2
#  ota: false
#  auth:
#    username: !secret ws_username
#    password: !secret ws_password

i2c:
  sda: 11
  scl: 12

bme68x_bsec2_i2c:
  # Default: 0x76 or 0x77
  address: 0x77
  model: bme680
  temperature_offset: 4.9 # 4.9
  # operating_age: 4d or 28d depending on how long your sensor has been running
  operating_age: 28d
  # sample_rate: LP => every 3 seconds (default). ULP => every 5 minutes
  sample_rate: LP
  state_save_interval: 6h

sensor:
  - platform: bme68x_bsec2
    temperature:
      name: "Temperature"
      id: "temperature"
    humidity:
      name: "Humidity"
      id: "humidity"
    pressure:
      name: "Pressure"
      id: "pressure"
      icon: "mdi:gauge"
    co2_equivalent:
      name: "CO2 Equivalent"
      id: "co2_equivalent"
      icon: "mdi:molecule-co2"
    breath_voc_equivalent:
      name: "VOC Equivalent"
      icon: "mdi:molecule"
    iaq:
      name: "IAQ"
      id: iaq
      icon: "mdi:approximately-equal"
    gas_resistance:
      name: "Gas Resistance"
      icon: "mdi:omega"

  - platform: absolute_humidity
    name: Absolute Humidity
    icon: "mdi:water"
    temperature: temperature
    humidity: humidity

text_sensor:
  - platform: bme68x_bsec2
    iaq_accuracy:
      name: "IAQ Accuracy"

  - platform: template
    name: "IAQ Classification"
    icon: "mdi:checkbox-marked-circle-outline"
    lambda: |-
      if ( int(id(iaq).state) <= 50) {
        return {"Excellent"};
      }
      else if (int(id(iaq).state) >= 51 && int(id(iaq).state) <= 100) {
        return {"Good"};
      }
      else if (int(id(iaq).state) >= 101 && int(id(iaq).state) <= 150) {
        return {"Lightly polluted"};
      }
      else if (int(id(iaq).state) >= 151 && int(id(iaq).state) <= 200) {
        return {"Moderately polluted"};
      }
      else if (int(id(iaq).state) >= 201 && int(id(iaq).state) <= 250) {
        return {"Heavily polluted"};
      }
      else if (int(id(iaq).state) >= 251 && int(id(iaq).state) <= 350) {
        return {"Severely polluted"};
      }
      else if (int(id(iaq).state) >= 351) {
        return {"Extremely polluted"};
      }
      else {
        return {"error"};
      }

  - platform: template
    name: "CO2 Classification"
    icon: "mdi:checkbox-marked-circle-outline"
    lambda: |-
      if ( int(id(co2_equivalent).state) <= 400) {
        return {"Excellent"};
      }
      else if (int(id(co2_equivalent).state) >= 401 && int(id(co2_equivalent).state) <= 1000) {
        return {"Normal"};
      }
      else if (int(id(co2_equivalent).state) >= 1001 && int(id(co2_equivalent).state) <= 2000) {
        return {"Unhealty"};
      }
      else if (int(id(co2_equivalent).state) >= 2001 && int(id(co2_equivalent).state) <= 5000) {
        return {"Health Risk"};
      }
      else if (int(id(co2_equivalent).state) >= 5001) {
        return {"DANGER!"};
      }
      else {
        return {"error"};
      }

ESP32 C3 Super Mini

This board is also know as esp32-c3-devkitm-1.
Board documentation available at: https://wiki.icbbuy.com/doku.php?id=developmentboard:esp32-c3mini

(same as the S2 example)

esp32:
  board: esp32-c3-devkitm-1
  framework:
    type: arduino

(same as the S2 example)

i2c:
  sda: 8
  scl: 9

(same as the S2 example)

Enjoy!