Telephone Remote switch
The described project utilizes a Dual-Tone Multi-Frequency (DTMF) tone detection system to enable remote control of household electrical devices via a mobile phone. The heart of the system is the AT89S52 microcontroller, an 8-bit device that provides the processing power necessary to interpret the DTMF signals received from a mobile phone.
The circuit incorporates the MT8870 DTMF decoder IC, which is responsible for converting the analog DTMF signals into corresponding digital signals that the microcontroller can understand. This IC detects the specific tones generated when a user presses buttons on their mobile phone and outputs a binary code that indicates which button was pressed.
In addition to the DTMF decoder, the system features a phone ring sensor circuit that monitors incoming calls. When a call is detected, the system can automatically engage, allowing the user to send DTMF commands without needing to establish a voice connection. This feature enhances the usability of the system, as it allows for seamless control of devices.
The microcontroller is programmed to recognize specific DTMF codes corresponding to six different devices, enabling the user to turn devices on or off as needed. Each device is connected to a relay or a solid-state switch, which is controlled by the microcontroller's output pins. This configuration allows for safe and effective switching of household appliances.
Overall, this project exemplifies the integration of telecommunications and microcontroller technology to create a versatile home automation system. The combination of the DTMF decoder and the microcontroller allows for a user-friendly interface that can be operated from virtually anywhere, providing significant convenience and control over household electrical devices.This Project is used to control our household electrical devices from any where through the cell phone. The circuit consists of a DTMF tone detector and a powerful 8 bit Microcontroller AT89S52. The microcontroller controls all the system. In this project we control total six devices. The Microcontroller senses the DTMF signal through the DTMF decoder IC MT8870 and it switch on/off the corresponding devices according to the user need. The circuit has an inbuilt phone ring sensor circuit and the system will take over the phone control i
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