Code for automatic calling for any given number is attached. Let us now write some code to give the live of the phonoduino. DTMF input is not given to the arduino now. Image of my complete phonoduino (phone + arduino) setup is given above. If you don't like to take burden of making this DTMF module you can use Seeedstudio DTMF shield, a very cool one. Put the terminal of the wire into fire for 2-3 seconds insulation will burn. You can use sand paper or use match fire to burn the insulation. For soldering these wires to the pcb you have to remove the insulation. Head wires are insulated by different colored insulation. speaker +ive is connected to the pin 2 of the IC through 104pf (104pf = 0.1uf) capacitor and 100k series resistor. Pin configuration of Nokia headphone jack is given herewith. Image of my complete DTMF module is uploaded above. Pin 5 & 6 should be connected to ground and pin 10 should be connected to vcc (this is not shown in schematic). For the resistor 100K you may use around 150K and for 300K around 400K may be used. Two 20pf capacitor is connected between crystal and ground (it is not mandatory, you may not use pf capacitor or you may use any in range of 15pf - 30pf). The circuit diagram of DTMF decoder/receiver is given above. I didn't add any resistor between transistor collector and keypad wire because according to phone schematic a resistor is internally connected to the signal pin of keypad. Pin headers are connected with base resistors through yellow jumper wire.Īfter making the board now carefully connect phone's keypad wire with the collectors of the transistors. For connecting arduino I/O port I added male pin header to the board. Image of transistors board is uploaded herewith. I connect phone ground and arduino ground together with the emitter of transistors. When connecting different circuit together for successful operation one thing must be remember, there must be one common ground connection among them whatever the other connection is. Pin configuration of 2N2222 is given above. You can find the datasheet of 2N2222 here. If you are interested to know more about transistor follow the link. When a digital pin of arduino become high the BJT turn on and work as like a press on the key of mobile phone. Arduino digital I/O pin is connected to the base of transistor through a current limiting resistor. Any other general purpose npn transistor such as BC547, 548 may be used. I used general purpose bipolar npn transistor (2N2222) for switching (on-off the phone key). Above schematic shows how arduino digital pins (D3 to D18) are connected to phone keys.
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