Publication

Abstract : Mobile phones can be used to transmit the signal to control devices. A method to transmit digital data to control a number of devices installed in a remote place is presented. DMTF (Dual Tone Multi-Frequency) coding technique is used to convert digital content to analog which is then transmitted over a line. DMTF is popularly known for analog telephone communication. Once the signal is converted and sent to the receiver the receiver decodes the signal into its digital form. All mobile phones and land line telephones keypad are DTMF generators for their corresponding digit. A DMTF decoder is attached to the telephone line and a microcontroller is used. When a ring is detected by the microcontroller then the call needs to be attended and by giving the feedback tone we can send DMTF code to control the remote device attached to the system using the sent data and then by terminating the call the device can be stopped. Using AVR Studio the programs are designed to control the AVR microcontroller. The binary combination of the number for the corresponding DMTF is fed into the microcontroller. Microcontroller controls the connected devices through relays and interfacing circuits. A password is also attached to this system for avoiding the improper usage. Hardware connections are first simulated in Fritzing simulation software.