I know its been asked before, but wondering if anyone has any ideas \ recommendations.
At its simplest I am looking for a Sensor that support a Temp Probe such as a DS18B20. I have seen recommendations for the Fibaro FGK's but those are about as rare a Unicorn Poop these days. Is there anything more current on the market?
At the core of my needs is this must be battery powered, so a Qubino Relay seems out the window.
My project is to set the probe in a Thermowell sealed to a water tight enclosure, the enclosure will house the sensor. When a set temp is breached (low-side) my pool pump and pool heater will fire off.
Requirements of this being battery based are that I do not have power anywhere near the pool, so I cannot use a mains powered device.
One of the simplest pool temperature sensor solutions that I have heard of is to simply place a contact sensor (that also reports temperature) in a vacuum sealed food preserver bag that is heat sealed. Then simply attached to the pool somehow underwater.
Another creative user, years ago, created a HubDuino/ST_Anything device to monitor pool temperature. In this case, I helped the user implement the ESP8266 Deep Sleep functionality to allow a battery powered device, to wake up, connect to WiFi, transmit a temperature reading, and then immediately back to sleep.
I do know how long the device lasted on battery power. If you want some assistance in trying to make this work, let me know.
How about the "Fibaro FBGS-222 Smart Implant", it has connections for a few external temp probes but I don't have one and never researched what kind of temp probes they support? You could actually have a probe before and after the heater to monitor both temperatures and stop heating before you overshoot the set temperature.
EDIT, just found the manual and it does support the DS18B20 temp probe.
Powering it with 4x 18650 Lithium cells in a battery holder will give you 14.4 volts (9-30V spec), and then getting a 18650 home charger when they are low. You would have to buy 8 cells so you have one set always ready to swap out.
This would be a lot cheaper than running mains power to the pool.