ESP8266 Temp Multi-Sensor

I built a WiFi sensor for my attic to monitor temperature, humidity, and pressure for less than $10 using

• Wemos D1 Mini clone
• BME280 (I2C temp/humidity sensor)

and with the home automation software Home Assistant with the EspHome plugin.

Here is my attic sensor’s display in Home Assistant:

Hardware

NOTICE: The GND pin of the sensor is NOT connected to pin D8 which is why the second pin has been removed from the header assembly. I used a wire to connect ground from accross the board.

Case

As always I have to find another reason to justify the purchase of my 3D printer. So I searched Thingiverse and found where “Spiritdude” had already created a nice case for the D1 Mini board, but the sensor location created problems for the left side mouting location, so I imported the STL file into SketchUp and moved the leg more to the top of the case.

Here is my modified version of Spiritdude’s case if you want to print your own.

Software

Here is my “Home Assistant ESP-Home” yaml config file for the Multi-Sensor.

esphome:
  name: attic_multisensor_01
  platform: ESP8266
  board: d1_mini

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_pass

captive_portal:

# Enable logging
logger:

# Enable Home Assistant API
api:

# Enable Over The Air updates
ota:

# Create BME Sensor on I2C
i2c:
  sda: D6
  scl: D7
  # Scan I2C address to look for sensors
  scan: True

sensor:
  - platform: bme280
    # Default address 0x77
    address: 0x76
    temperature:
      name: "Attic Temperature"
      id: attic_bme280_temperature
      filters:
        - lambda: return x * (9.0/5.0) + 32.0;
      unit_of_measurement: "°F"
    pressure:
      name: "Attic Pressure"
      id: attic_bme280_pressure
    humidity:
      name: "Attic Humidity"
      id: attic_bme280_humidity
      filters:
        - calibrate_linear:
          # Map 0.0 (from sensor) to 0.0 (true value)
          - 0.0 -> 0.0 
          - 32.7 -> 55.7
    update_interval: 15s