This project “DTMF REMOTE APPLIANCE CONTROL SYSTEM USING MOBILE PHONE” is used to control appliances which are far away from the user using mobile phone. The aim of the proposed system is to develop a cost effective solution that will provide controlling of home appliances remotely and enable home security against intrusion in the absence of homeowner.
The devices connected as home and office appliances consume electrical power and they should be controlled as well as turn on /off if required. Most of the time, it was done manually. Now it is a necessity to control devices more effectively and efficiently at anytime from anywhere. Take an instant when we are going to office and suddenly remembered that to switch off the microwave oven we fell convenient if we could switch off without going back to home, in such situations this project comes to our rescue.
In this system, we are going to develop a cellular phone based home/office appliance controller for controlling arbitrary devices. This includes a mobile phone which is connected to the system via head set. To activate the mobile phone unit on the system, a call is to be made and as the call is answered (auto answer mode), in response the user would enter a password to access the system to control devices. As the caller presses the specific button on the keypad, it results in turning ON or OFF specific device and the device switching is achieved by relays.
In this project, we designed a basic model and it is used to control 4 lights using a mobile phone, micro-controller and transceiver. The maximum number of devices that can be operated will be the number of buttons present on the keypad of mobile phone.
1.1 Block diagram:
Figure 1.1: Block Diagram
Fig 1.1 represents the block diagram of DTMF Remote Appliance Control System using Mobile phone, used to control the appliances present at a distance.
Brief Description of Hardware Modules:
The DTMF Remote Appliance Control System consists of
1. Mobile Phone
2. MT8888 DTMF Transceiver
3. Philips 89C51 Micro-controller
4. Liquid Crystal Display
5. Power Supply Unit
6. Relay Driver
1.2.1 Mobile Phone:
Mobile Phone is used as a media to instruct the micro controller to power ON/OFF the appliances. The mobile phone used here is Nokia 6030 as it has the required features and is interfaced with the transceiver through ear phones.
1.2.2 MT8888 DTMF Transceiver:
The MT8888C is a monolithic DTMF transceiver with call progress filter. The transceiver consists of transmitter and receiver. The DTMF signals are transmitted through transmitter and they are received by the mobile phone and decoded using a DTMF receiver/decoder IC’s.
1.2.3 PHILIPS 89C51 Micro Controller:
The PHILIPS 89C51 is a low cost micro-controller. It has a 40 pin configuration and contains non volatile Flash memory of 64KB which is both parallel programmable and serial in system programmable memory.
1.2.4 LCD display:
The LCD unit receives character codes (8 bits per character) from a microprocessor or microcomputer, latches the codes to its display data RAM (80 byte DD RAM for storing 80 characters), transforms each character code into a 5x7 dot matrix character pattern, and displays the characters on its LCD screen.
1.2.5 Power Supply Unit:
The power supply unit is used to provide a constant 5V supply to different IC’s. This is a standard circuit using external 12V DC adapter and fixed 3-pin voltage regulator. Diode is added in series to avoid reverse voltage.
1.2.6 Relay Driver:
The ULN2003 is a high-voltage, high-current darling ton driver comprising of seven NPN darling ton pairs. For...