Temperature and humidity alarm circuit

It continuously monitors necessary environmental parameters (temperature, humidity, illumination, etc.). If
the parameter exceeds the allowed value, an alarm signal will be automatically sent out and the actuator can also be switched on.
    The alarm consists of two parts: an electronic relay and a signaling device. Depending on the use occasion,
the following types of sensors and electronic relays are used: thermal relay (when connected to a thermistor); photoelectric relay (when connected to
a photoresistor or photodiode); humidity indicator ( When connected to a hygroscopic resistor), etc. The action threshold value t of the device can be achieved by appropriately selecting the resistor Ri and adjusting potentiometer RP
    by connecting to the corresponding sensor (such as temperature , humidity, etc.).