Marpaung, Noveri Lysbetti2014-02-032014-02-032014-02-031693-9573wahyu sari yenihttps://repository.unri.ac.id/handle/123456789/5462This research is aimed to observe the principle procedure of Temperature Logger Data Sensor based on Atmega 8535 Microcontroller with Personal Computer Display. This research uses method for designing equipment simulation for detecting and recording temperature in a room or things for every second. Therefore, the function of Temperature Logger Data Sensor is to measure and display the temperature continuously through PC monitor. The type of temperature censor used is DS1621 which can measure temperature from 0°C up to 50°C. The data is processed in Atmega 8535 microcontroller, and then the result is sent to PC monitor through RS232 which display data in table. Visual Basic 6.0 is used to create database and display data in monitor. The result of the study shows that the Temperature Data Logger Sensor can be used to measure temperature of rooms or things which fluctuation range of 0,5° C and the error of 2,03%. The Temperature Data Logger Sensor based on the Atmega 8535 microcontroller works according to the procedureenData Logger, DS1621 Temperatur Censor,Microcontroller ATmega 8535232 Interface SerialThermocoupleData LoggerDS1621 Temperatur CensorUR-Scientific Work Lecturer