No Zigbee on the roof
Today is the end of my attempt to get sensors on the roof.
The problem: I have solar water heating on the roof of my building. On cloudy days I need to heat water with electricity, on most days (when it’s sunny) I don’t. Before switching on electrical boiler I want to know what is current temperature of the water in the tank.
This is, actually, very complicated problem, because tank is pressurized, insulated and made of of metal. I’ll write full report when I solve it, but current idea is to use contact sensors to get temperature from the outer wall of the tank in place where there is no thermal insulation. But before doing it I was worried if I get Zigbee there or not.
Turned out, nope, I can’t.
I found a decent Zigbee contact temperature sensor for my needs: THS-317-ET
It should work, but only if I get Zigbee on the roof.
What I done: I took one of unused relays (which is Zigbee router), but it into the box, and with big electrical extender put it on the balcony.
I also put a normal thermal sensor on the roof, right on the edge, and waited. (Before doing it I reinitialized it to get link with the relay and got temperature reading on the balcony).
I moved sensor on the roof, and…
And nothing. Even in best possible conditions (no concrete slabs, almost direct visibility) it can’t traverse just 6 meters up for unknown reason.
May be it need reflections from walls to work? May be even small border on the roof is enough to block the signal? Anyway, it can’t.
This is unfortunate results and I will need to use different protocol to make it work. I’ll test BLE (fat chance it will work, but…), but insofar ESP with DS18B20, running ESPHome is my next attempt.
Insofar, conclusion: Zigbee is not good even for moderate distances outdoor.
