Temperature sensor circuit

[Fantascy]

Plz i need help with this circuit design. I want to design a temperator sensor circuit that will be comparing the temperature of the surrounding with a fixed ref temperature. The output of the circuit should be logical high for temperatures less than 50'c and a logical low for temperature greater than 50'c. The temperature sensor to be use is Lm35D and the comparator should be Lm311. I'll appreciate your circuit diagram. Thanks

 

[MikeMl]

Sounds like a class project. Your description is confused. Are you comparing the temperature of the LM35 to an ABSOLUTE reference, or to a second LM35 which is in a different thermal environment?