Water temperature sensor

Manic · October 1, 2019, 12:18pm

Hi

Im currently in the process of building my house and Im considering the HestiaPi to replace the dumb water heater switch that will be installed. I am wondering if the hestiapi could operate a standard solar water heater but also monitor the water temperature while doing so, to further automate the process with thresholds etc.

Obviously to do so a temperature sensor would need to be added to the solar heater’s water tank, but as per your FAQ and this: BME280.py script not pulling set point/current temp the DS18B20 which can be bought waterproof is not supported.

What would you suggest for this scenario?

Thanks

HestiaPi · October 1, 2019, 6:15pm

We stopped maintaining multiple sensor technologies but we believe the code still works.
The DHT file is still delivered (disabled) with HestiaPi but is not tested:

github.com

HestiaPi/hestia-touch-openhab/blob/master/home/pi/scripts/AdafruitDHTTemp.py

#!/usr/bin/python
# Copyright (c) 2014 Adafruit Industries
# Author: Tony DiCola

# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

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If you have a Pi Zero with Raspbian stretch and the DHT to test that would be your safest option but I am sure if you google around you will find lots of examples.
Once you get the electrical connection with the sensor the rest is pretty straight forward to modify for the UI to show current water temp and adjustable setpoint (target) temp that will be available in the App and the Web interface… We can help with that part

Manic · October 1, 2019, 7:55pm

Thanks for the quick reply! I noticed the dht support, however all dht sensors appear to be temperature & humidity sensors, and therefore are not waterproof.
Ideally I would need something like the DS18B20 which is fully waterproof and can handle around 100c. Is there a compatible waterproof temp sensor that could be used?

Thanks

HestiaPi · October 1, 2019, 8:01pm

A quick search seems that it is surely compatible and you will find plenty of sample code for DS18B20.
https://www.raspberrypi.org/forums/viewtopic.php?t=214735
so I wouldn’t worry too much. Make sure you wire the sensor correctly and you remove the internal BME280.

Manic · October 1, 2019, 8:51pm

Excellent, thanks!

Arden · January 4, 2020, 10:20pm

I have a waterproof DS18B20 in a hot water tank attached to a esp8266 reports back to openhab via mqtt