In The Heat Of The Night – 1-Wire Temperature Sensor Directly Immersed

As always, I want to first quickly explain, what brought me to that project… If you look around in different stores and on aliexpress, you can find a ton of 1-wire temperature sensors with stainless steel sleeves. But they are all 6 mm or the are wrapped with a shrinking tube, that avoids to use it as a immersed temperature probe. What I needed was a sleeve with 5 mm (or 5.2 mm) diameter and grooved at the end to be used in standard probe holes like with this ball valve.

The tricky point is, that the default DS18B20 in TO-92 case are a bit to fat, to fit in a 5 mm tube. But the DB18B20U is the starving brother and thin enough to fit in, if placed on an appropriate PCB (0,6mm). So, I decided to design one and give it a try…

And after only a few days, my order from PBCway arrived… You will find it on GitHub.

It only took a few minutes to solder the components…

And after connecting it to some ESP32 that was lying around and adding the config to ESPhome, the sensor quickly showed up in ESPhome.

esphome:
  name: ow-test32

esp32:
  board: esp32dev
  framework:
    type: arduino

# Enable logging
logger:

# Enable Home Assistant API
api:

ota:
  password: "somepass"

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

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "Ow-Test32 Fallback Hotspot"
    password: "some-other-pass"

captive_portal:

dallas:
  - pin: 13
    update_interval: 5s

# Individual sensors
sensor:
  - platform: dallas
    address: 0x30000001243bfc28
    name: "Test OWire"

That was easy and I already found an appropriate sensor cable and ordered it already. For grooving, I need to build me some tools and I’ll share that information.

Update: I’ll contact another sensor supplier and ask, if they can provide this sensor.

The best fit steel tubes can be found on aliexpress.

If you are interested to get some of the PCBs for testing or fully assembled sensors, please let me know 🙂

I’ll provide an update soon.

Happy digging!