Code for https://twitter.com/TathamOddie/status/1398526121008762881

air_monitor_indoor.yaml

# Used with ESPHome. See https://tatham.blog/2020/08/30/esphome-nothing-to-firmware-in-30-minutes/

## Commom pieces of text we'll re-use later
# (makes it easier to copy and paste all of this code for another value later,
# because you only have to set the new name at the top of the file)

substitutions:
  device_name: air_monitor_indoor
  friendly_name: Air Monitor Indoor
  area: Indoor

## Board config

esphome:
  name: ${device_name}
  platform: ESP32
  board: m5stack-core-esp32


## Boilerplate, same for all of our devices

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password
  ap:
    ssid: "Fallback ${friendly_name}"

api:
  password: !secret esphome_secret

ota:
  password: !secret esphome_secret


## Hardware setup

# Move the log output off the main UART so it doesn't conflict with the particle sensor
logger:
  hardware_uart: UART1
  level: VERBOSE

uart:
  rx_pin: GPIO25
  tx_pin: GPIO21
  baud_rate: 9600

sensor:
  - platform: wifi_signal
    name: ${friendly_name} WiFi Signal Strength
    update_interval: 60s

  - platform: uptime
    name: ${friendly_name} Uptime

  - platform: sds011
    update_interval: 5min
    pm_2_5:
      name: "${area} Particulate Matter <2.5µm"
    pm_10_0:
      name: "${area} Particulate Matter <10.0µm"