Not sure if this might help, I've got an esp in my Hotspring spa which I've converted to be "WiFi" enabled. The esp also control the temperature of the spa. I had problem figuring out how to have a variable like set temperature and then do things like compare the water temperature and turning on the heater. What I ended up doing is to use a dummy device -
Device1
Device: Temperature - DS18b20
Name: DS18B20
Delay: 60
IDX/Var: 1
1st GPIO: GPIO-2
Send Data: Yes
Value Name 1: Temperature
Device4
Device: Dummy Device
Name: SetTemp
Delay: 60
IDX/Var: 4
Simulated Data Type: SENSOR_TYPE_QUAD
Send Data: Yes
Decimal Temperature: 1
Decimal Auto: 0
Decimal TempLow: 1
Decimal TempHigh: 1
Value Name 1: Temperature
Value Name 2: Auto
Value Name 3: TempLow
Value Name 4: TempHigh
"Temperature" is what I set the target temperature of my spa, "Auto" is to indicate if I want the esp to control the heater and "TempLow" & "TempHigh" is when to turn on and off the heater. I was going to have a couple of switches and also a display, but they haven't been implemented yet. Until then, I am sending the data across via OpenHAB.
Here's part of my rules -
on DS18B20#Temperature do
if [DS18B20#Temperature] > [SetTemp#TempHigh]
event,TurnOff
endif
endon
on DS18B20#Temperature do
if [DS18B20#Temperature] < [SetTemp#TempLow]
event,TurnOn
endif
endon
on TurnOn do
if [SetTemp#Auto] > 0
gpio,13,1
else
gpio,13,0
endif
endon
on TurnOff do
gpio,13,0
endif
endon
on SetTemperature do
TaskValueSet 4,1,%eventvalue%
TaskValueSet 4,3,%eventvalue%-0.5
TaskValueSet 4,4,%eventvalue%+0.6
endon
on SetAuto do
TaskValueSet 4,2,%eventvalue%
endon
To set the temperature you can either send via a standard http -
Example of setting the temperature to 37 degree -
http://192.168.1.xx/control?cmd=event,SetTemperature=37
Example of turning on auto -
http://192.168.1.xx/control?cmd=event,SetAuto=1
Or do it in OpenHAB rules -
sendHttpGetRequest("
http://192.168.1.xx/control?cmd=event,SetTemperature=" + TargetTemperature)
where TargetTemperature is the value of the target temperature you want the spa set to
Hope that helps.
Cheers!