WORLDWIDE REMOTE DEVICE ACCESS SYSTEM
- 1. WORLDWIDE REMOTE REMOTE DEVICE ACCESS SYSTEM
- 3. WORLDWIDE REMOTE DEVICE ACCESS SYSTEM In this project we can access four devices from anywhere. We can on or off the devices with the help of cell phone. User has to dial the the phone no that is attached with with the device. User can off or on the device at any time. If he will not press any no. then after 20 sec phone will be disconnected automatically.
- 4. DTMF SIGNALS The DTMF is a popular signaling method between telephones and switching centers DTMF is also used for signaling between the Telephone network and computer networks The DTMF signals are Transmitted over a telephone line Uses speech frequency signals DTMF signals are the superposition of 2 sine waves with different frequencies
- 5. The DTMF Keypad 1209 Hz 1336 Hz 1477 Hz 697 Hz 1 2 3 770 Hz 4 5 6 852 Hz 7 8 9 941 Hz * 0 #
- 6. TONES
- 8. WAVEFORMS OF DTMF DIGITS
- 10. BLOCK DIAGRAM IN this project we will control four devices with the DTMF technique. These four devices may be your fans, bulbs, motor etc. PHONE LI NE DECODER PIC (MICROCONTROLLER) DEVICES POWER SUPPLY
- 11. PARTS USED ARE PHONE LINE : It will be the medium in which mobile or phone signal travels DECODE R: It will decode the mobile signal to appropriate signal that can drive uC.CM8870 is the dtmf decoder used in this project. PIC : PIC is a family of Harvard architecture microcontroller made by Microchip Technology, derived from the PIC1640 originally developed by General Instrument 's Microelectronics Division. The name PIC initially referred to " Peripheral Interface Controller ". PICs are popular with developers and hobbyists alike due to their low cost, wide availability, large user base, extensive collection of application notes, availability of low cost or free development tools, and serial programming (and re-programming with flash memory) capability. In this project we will use 16f877A microcontroller. POWER SUPPLY : it will provide provide supply of 12v,5v to the uC and decoder. DEVICES : It may include fan, motor, tubelight etc.
- 12. ALGORITHM WHEN phone will ring PIC will detect the ring and it will hold the phone after ten rings. 2) Then digit from transmitter is decoded by cm8870 and it is sent to PIC. 3) If the Code matches with the address of devices it will switch ON or off the corresponding device.
- 13. APPLICATION OF DTMF Voice mail Helpdesks Phone banking Computer remote login Remote appliances control etc. Stock broker buy/sell/inquire -using stock exchange listing mnemonics Credit card verification and inquiry Answering machine message retrieval
- 14. FUTURE SCOPE Password protection can be added It can also used for controlling the speed of stepper motor. DTMFcan also be applied from computer. it means devices can also be controlled from remote computer via internet.
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