Implementation of an Automatic Door Lock System Using DTMF Signal of a Mobile Phone

모바일 단말기의 DTMF 신호를 이용한 자동 도어락 시스템 구현

  • 배기원 (제주대학교 통신컴퓨터공학부) ;
  • 양두영 (제주대학교 통신컴퓨터공학부)
  • Published : 2006.01.01


In this thesis, an automatic door lock system using a dual tone multiple frequency(DTMF) signal generated as pushing the key button of mobile phone is proposed and implemented. This system consists of a transmitter module and a receiver module for processing the DTMF signal of mobile phone. The DTMF signal of mobile phone connected with ear-phone jack enter into the input terminal of DTMF receiver and those are encoded by a code-converter with 4-bits binary format in the DTMF receiver. The encoded output signals are transmitted to the amplitude shift keying(ASK) modulator of transmitter module and the modulated ASK signals which are converted into radio frequency(RF) signals propagate in a free space. The RF signals passed through a free space are demodulated by the ASK demodulator of receiver module and the demodulated ASK signals are sent to a micro-controller unit(MCU). The output signals processed by the MCU are compared with the secreted identification number which is prerecorded in a microprocessor and are transferred to a power relay. If the result is the same, the automatic door lock system opens a door. In the opposite case, it maintains closing the door. The implemented automatic door lock system operates well in mobile environments.


DTMF Receiver;ASK Modulator;ASK Demodulator;MCU;Door Lock