Raspberry Pi with DS18B20 temperature sensors

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Raspberry Pi with shield for 5 DS18B20 temperature sensors

Raspberry Pi driven temperature sensors for fan control of the home lab/office.

Details

• Set up Raspberry Pi; Raspberry Pi IoT setup
• Enable 1-wire communication with raspi-config
• Install python package sudo apt install python3-w1thermsensor

List devices:

$ ls /sys/bus/w1/devices/
28-0416a02b0eff  28-0517021db9ff  28-051702869eff  w1_bus_master1

Raw read the value:

$ cat /sys/bus/w1/devices/28-0416a02b0eff/w1_slave 
8e 01 4b 46 7f ff 0c 10 de : crc=de YES
8e 01 4b 46 7f ff 0c 10 de t=24875

Temperature = 24.875'C

Home Assistant configuration

Home Assistant temperature group

sensor:
  - platform: mqtt
    state_topic: 'sensor/office/temp/above_rack'
    availability_topic: "sensor/office/temp/above_rack/status"
    name: 'Office ceiling above rack'
    unit_of_measurement: '°C'
  - platform: mqtt
    state_topic: 'sensor/office/temp/above_desk'
    availability_topic: "sensor/office/temp/above_desk/status"
    name: 'Office ceiling above desk'
    unit_of_measurement: '°C'
  - platform: mqtt
    state_topic: 'sensor/office/temp/room_center'
    availability_topic: "sensor/office/temp/room_center/status"
    name: 'Office ceiling center'
    unit_of_measurement: '°C'
  - platform: mqtt
    state_topic: 'sensor/office/temp/average'
    name: office_temp_average
    unit_of_measurement: '°C'

Fan automation

- alias: Fan on auto
  trigger:
    platform: numeric_state
    entity_id: sensor.office_temp_average
    above: 25
  action:
    service: switch.turn_on
    entity_id: switch.office_fan

- alias: Fan off auto
  trigger:
    platform: numeric_state
    entity_id: sensor.office_temp_average
    below: 24
    for:
      minutes: 5
  action:
    service: switch.turn_off
    entity_id: switch.office_fan

Source code

Source code is available in a git repository:
https://github.com/thomasjsn/rpi-w1therm

Gallery

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• Temperature probes
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• Previous probe placement
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Schematic diagram