CONTENTSINTRODUCTION OF PROJECTINTRODUCTION OF MICROCONTROLLER 8051INTRODUCTION OF DTMFINTRODUCTION OF MAX 232WORK DETAILRESULTCONCLUSION
INTRODUCTION OF PROJECT • This project is to develop a device that allows for a user to remotely control home appliances using a cellular phone.This system will be a powerful and flexible tool that will offer this service at any time, and from anywhere .The control system will include two separate units: the cellular phone, and the control unit.There will be two operating environments. The cellular phone operates indoor and outdoor and control unit operates indoor.
INTRODUCTION OF MICROCONTROLLERA microcontroller is an economical computer-on-a- chip.It is a small and low-cost computer ,which performes specific task.Microcontroller has an input device in order to get the input and an output device (such as LED or LCD Display) to exhibit the final process.The 8051 has three very general types of memory to effectively program the 8051 it is On-Chip Memory, External Code Memory, External RAM.A microcontroller has a CPU(a microprocessor) in addition to fixed amount of RAM, ROM, I/O port and a timer all on single chip. therefore the designer cannot add any external memory, I/O ports or timer to it.
INTRODUCTION OF DTMFThe DTMF tone decoder IC converts the received tones to their respective binary values and then gives them as an input to the microcontroller.Its filter section uses switched capacitor technology for both the high and low group filters and for dial tone rejection. Its decoder uses digital counting techniques to detect and decode all 16 DTMF tone pairs into a 4-bit.
The DTMF keypad is laid out in 4*4 matrix with each row representing a low frequency and each column representing a high frequencyThe DTMF tone decoder IC’s internal architecture consists of a band split filter section which separates the low and the high tone of the received tone pair.
INTRODUCTION OF MAX 232The Max 232 is a dual driver/receiver that includes a capacitive voltage generator to supply EIA-232 voltage levels from a single 5V supply.The MAX 232 is to connect a serial port device to a serial port which uses the RS232 standardThe serial port device is usually a UART(universal asynchronous receiver/transmitter)
WORK DETAIL This project is to develop a device that allows for a user to remotely control home appliances using a cellular phone. The system requires two phones out of which the one present at the control unit has to be a cell phone with auto answer facility. The person who wants to switch on/off any device makes a call from mobile phone. Once the call gets picked up, presses the key for a corresponding device. The mobile phone on the receiver side picks up the phone automatically after 5seconds, and then makes the tones available to the DTMF tone decoder IC through the headphone jack of the phone.
The DTMF tone decoder IC converts the received tones to their respective binary values and then gives them as an input to the microcontroller. DTMF verifies both the frequency and duration of the received tones and pass the resultant 4-bit code to the output bus.The output from DTMF IC is given into the MICROCONTROLLER 8051.
RESULT & CONCLUSIONWe have successfully completed the project “DEVICE ON OFF THROUGH MOBILE PHONE”This project is very useful now a days as well as its cost is very low, so anyone can afford it and use it.