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Home Security system





Auto Dialer Circuit 



In this project we show that how we use the telephone as a electronics eye. With the help of landline phone we check and examine the position of the house automatically. In this logic we attach some sensor with the telephone and if there is any miss happening then telephone is automatic on and then circuit press the redial button of the telephone and then  telephone dial the  pre-dialed number. All  these logic is to be divided into few parts.




Sensor unit.


Micro controller interface


Switch on the telephone


Redial the number



Switch off the telephone line after sending the message.

Voice processor circuit  IC ISPVP 2000



In this sensor unit  it is our choice , how many sensor’s  we use , IN this project we use two sensor’s, In this project we use two electronics circuit with infra red sensor’s and fire alarm sensor.

negative voltage as a pulse to the microcontroller.


If we connect two sensor as a input to the microcontroller then we use same


 After pressing the flash button, redial button and switch on the telephone line we switch on the memory ic. We use relay circuit to switch off/on hook the telephone line.

Telephone dialer circuit.

 In this portion of telephone dialer circuit we  use the   telephone dialer circuit.  For this we use one dtmf generator circuit to generate a dtmf tones from the circuit. For this purpose we use one DTMF generator circuit to generate a dtmf tones from the circuit. We connect one telephone keypad  or push to on switches with this circuit. We use total 14 push to on switches with this circuit to dial the dtmf tones. Once we dial the number in the  dialer circuit. Now when micrcontroller press the redial switch then circuit is on and  redial the  pre-dial number .

All the switches are connected to the pin no no 12,13,14,15,16,17,18. All the switches are connected in row and matrix combination including redial and flash switch.     

Voice Processor circuit- In this project we also used voice processor circuit having 60 sec recording/playback functionality. We can save 8 voice tags in this IC. 




Components required:

Ic 91214

IC IPSVP- Voice Processor

89S52- Mircontroller

Condensor Mic


104 pf

push to on switches

.001 µf,0.1 µf,0.01µf



crystal 11.0592 MHz

3.38 MHz.


speaker 8 ohm

relay 12v 100 ohm

transformaer 6v 500mA

infrared Sensor,


connecting wires

copper clad board




·       Easy to implement

·       Reliable,

·       Low cost,

·       Components easily available in market.



Advantage of using this calling technology as compare to SMS via GSM modem:-

·        Low cost- hardware component are not costly. GSM modem cost is quite large then using calling  function.

·        Reliability –this quite reliable when we studied ongoogle search. GSM network sometime doesnot work because of weather problems.

·        Component easily availbe in te market. Otherwise GSM module not easily available