The Fly-RRF-36 has a temperature sensor on the PCB, that can be used to monitor the chamber temperature.
Use the following line to activate the temperature sensor.
M308 S2 P"124.temp1" Y"thermistor" A"Chamber Temperature" T100000 B4092
The sensor can be added to the temperature graph by selecting
extra on the heater control panel in DWC.
The sensor can also be used to trigger a fan etc when a certain threshold is met.