The purpose of this project is recording EEG data from user, and developing drowsiness detector system application as solution for accident problem caused by drowsiness. Hardware that used in this project is NeuroSky Mindwave, which is noninvasive EEG reader that available commercially in market. This device has a special function that called eSense. eSense are copyrighted special algorithm belong to NeuroSky that is used to classification certain brain wave. The wave that named Meditation and Attention, which is used in this project to detecting mental condition of user. Drowsiness is the most concerned factor is safety especially for the driver who need high concentration and must stay focus in relative long time. Drowsiness in driving is the most contributed factor for on-road-accident. This problem can be prevented with using modern technology. Braincomputer interface (BCI) with input from electroencephalographic (EEG) can be used for measuring brain activity level. With EEG signal we can gather important information about mental condition of someone, like drowsiness and tiredness. For that an application is needed to give an alarm or warning for driver when he/she feels drowsy to take a rest. With using brain wave censor hopefully this application can give an early warning and real time warning for driver.