/Projects/Phone call alert

After putting together this little device, you must enter programming-mode to learn some phone numbers which this module will call after detecting an input on it's sensor pin.

After programming just supply power to the device. After pressing the button "Pokreni dojavu alarma" it will start to dial (tone or pulse, depending on the jumper setup). When the phone call is succesfully established, the called party should press pound key "#" to stop the device from calling another number or again.

UPDATE: Source code is now available for download!


You should put a sensor instead of button "Pokreni dojavu alarma".

Programming the numbers

- press the "program" button
- pick up the phone that is connected to the same phone-line as this device
- punch-in first number and then "*" key
- punch-in then next number and then "*" key
- punch-in the rest of numbers, if more, and finalise with "*#" (example: 061123123*061456456*#)

Please note: The device will learn 64 characters/digits including * and # keys.


Author (sent by): Trax

Download counter: 16,881

Rating: (2.95, votes 3403)


Date: 17-02-2007

Lokalna verzija ove stranice: Phone call alert


Bookmark and Share Comments (67)

comment [57]

Are you sure you don't need to use 1-3 as primary, and 4-6 as secondary? Why don't you try that. Also, you should take earphones and connect them to the output of transformer, actually between pin 2 of MT8880 and GND. You must hear DTMF tones when you press buttons on the other phone!
IP: n/a

comment [56]

By the way. I am using a 9V battery as power source and 7805 to feed the project.
IP: n/a

comment [55]

We need to go step by step... look. I am using this transformer: 42TL016-RC. there are 6 pins. reading the datasheet, I need to use 1 and 2 for primary and 4 and 5 for secondary. What do you think?
IP: n/a

comment [54]

when I turn on the project, tone from telephone goes down.
IP: n/a

comment [53]

On each DTMF tone you press on your phone, the LED should turn off for a second. In you case it doesn't turn off and that's because the alarm is not receiving DTMF tones from your phone. You should try removing those zener diodes and those 1N4148 diodes after the transformer to see what happens!
IP: n/a

comment [52]

My transformer does have 6 pines. It is suppose that I should use 4 only. 1 & 2 for primary and 4 & 5 for secondary. Would be nice that you test again this project and let me know exactly what the led do. let me tell you my results: 1. turn on an led blinks 2. press program button and led stops flashing (stay on) 3. finish the phone number with # and LED remains on. 3a. if I press sensor nothing happening 3b. if I press program button, led blinks again so I press sensor and relay actuates... would be great that you post a video here with the project operation... ;)
IP: n/a

comment [51]

You must connect this device on the telephone line that also has a phone connected to it. When you pick up the phone, you should also press PROGRAM button on this alarm device. Then you start entering numbers that it will call. Each number must end with * key, and after the last one you must enter *#. You do not need to press PROGRAM button to exit programming mode, the key # exits from programming.
IP: n/a

comment [50]

I have tested.... :( Something is wrong or I did not understood the operation. I think the number is not being programmed. As I understand, I need to connect to the phone line together with the telephone. I will use the telephone keyboard to program the PIC once I have pressed the program button. Is not clear what happen when I press the # key. I need to press the program button again to return to "wait for sensor" status?
IP: n/a

comment [49]

I have not tested YET. How can I share you an image? I would like to have your point of view about proto board connections.
IP: n/a

comment [48]

Hello, yes, you can put 2.3 diodes instead. These diodes are limiting audio signal that is entering MT8880 chip. They are used to protect this IC. You can also put another 1N4148 diode in parallel with the other one, but reverse polarized.
IP: n/a

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