Call A handphone using Microcontroller PIC16F877A

[E11022]

Hi,

i am having a big problem which need to be solved within a week.
First, i am doing a simple alarm system. When the sensor detects break in, the speaker will sounds and at the same time, the handphone that is connected to the PIC will call 999 or pre-determined number.

I am done with the Sensor- PIC- Alarm(Buzzer).

Now, i dont know how to do the programming and connections for PIC-Handphone.
I plan to use R2R to generate DTMF tones like below:

Project

I am not sure of the circuit for PIC and R2R. Now, i am just connecting R2R input D0-D7 into my PIC Port D. Is this correct? Then the Output pin and GND pin of the R2R circuit will connect to my Handphone.

R2R

1.GIF (5.68 KiB) Viewed 6958 times

P/S: I am using PIC16F877A and i planned to use NOKIA 3310 as the handphone(recycle the phone).

I research online for some time and i am blur now. I saw examples using RS323, MAX ic, Tone generator, Amplifier, GSM modem, SMS, AT command, Hyperterminal. All this making me becoming more and more confused.

Please advice me on how to do the circuit connection from PIC to R2R and Handphone
AND also please teach me how to write programming for the DTMF tones in order for my handphone to auto-dial a number while break in happens?


Thanks.
From,
Alice

[Brian Griffin]

Do you have a GSM modem? If you have it, connect it through the serial interface, send commands to the modem by using the microcontroller.

If you need to connect the thing to the land-line, you may need to use the DAC and to generate the tones. Note that tone-generation can be very difficult for staters.

[E11022]

Do you have a GSM modem? If you have it, connect it through the serial interface, send commands to the modem by using the microcontroller.

If you need to connect the thing to the land-line, you may need to use the DAC and to generate the tones. Note that tone-generation can be very difficult for staters.

No, i do not have a GSM modem, but i saw samples online where they used Handphone as the GSM modem, but i am not sure about the connections.

I am not connecting the PIC to land-line but to a HANDPHONE, but i am not sure of how to make the PIC send commands to my handphone( call 999).

[low5545]

To dial a number/send a SMS, we don't use DTMF tones to communicate, we use AT Commands. It's better to use a GSM modem instead of a handphone although they are more expensive. We couldn't know if they are compatible with AT Commands. Its difficult to calling a number but we can still send SMS (you can always SMS the police's SMS line - 32728) We communicate to the GSM Modem through UART. You'll need a RS232 to TTL converter circuit (MAX232...) as the GSM Modem uses a RS232 interface while the MCU TTL (5V). To know more about AT Commands, try these links:

http://www.smssolutions.net/tutorials/gsm/sendsmsat/

http://www.developershome.com/sms/howToSendSMSFromPC.asp

http://www.activexperts.com/serial-port-component/at/nokia/

Hope this helps.

[E11022]

To dial a number/send a SMS, we don't use DTMF tones to communicate, we use AT Commands. It's better to use a GSM modem instead of a handphone although they are more expensive. We couldn't know if they are compatible with AT Commands. Its difficult to calling a number but we can still send SMS (you can always SMS the police's SMS line - 32728) We communicate to the GSM Modem through UART. You'll need a RS232 to TTL converter circuit (MAX232...) as the GSM Modem uses a RS232 interface while the MCU TTL (5V). To know more about AT Commands, try these links:

http://www.smssolutions.net/tutorials/gsm/sendsmsat/

http://www.developershome.com/sms/howToSendSMSFromPC.asp

http://www.activexperts.com/serial-port-component/at/nokia/

Hope this helps.

Oh, i thought DTMF can be used too.. >.<
Just 1 question, if i use a GSM modem communicate through UART, it is definitely connected to PC??cause i need an individual circuit.

[low5545]

No. can also use PIC, Arduino.....

[E11022]

Okay, thanks Low. Let me do further research on it. Thanks lot
Btw, why handphone cnt use DTMF tones?

[low5545]

Never seen one, but it may just do it. Better stick to a GSM Modem.

[E11022]

Thanks LOW..i gonna start fighting for it..left few days to settle it.. Thanks lot. Ur advice really help me

[low5545]