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.
· Easy to implement
· 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