1$ Wireless Device to Control Arduino From Anywhere

#DTMF stands for DUAL TONE MULTIPLE FREQUENCY , in which we are going to use Mobile phone to make its as a wireless device, it works on the frequency which we generate on keypad of caller phone.

Step 1: How It Works?

There are two frequency groups in keypad of mobile phone ,combination of these two will form Dual tone multiple frequency ,in simple
words by adding or mixing two or more frequencies
generates DTMF tone.

Step 2: Output of DTMF Module !

Observe the pics ,Here we get a tone from our cellphone by using aux wire to
DTMF Decoder IC namely MT8870 which decodes the tone
into digital signal of 4bit.

whenever we press any key on keypad of mobile we get different output which is indicated by using LEDs on module , if you look at the images carefully you can find different output for different keys

Step 3: Interfacing It to Arduino

Arduino UNO is used for controlling whole process ,Arduino reads commands sent by
DTMF Decoder and compare with define code or pattern.
here we connect Digital io pins of Arduino to the Output pins of DTMF module .

Step 4: Circuit and Code

#define D0 5
#define D1 2
#define D2 3
#define D3 4

void loop()
{
int temp1=digitalRead(D0);
int temp2=digitalRead(D1);
int temp3=digitalRead(D2);
int temp4=digitalRead(D3);

if(temp1==0 && temp2==1 && temp3==0 && temp4==0)
{

// your statements
}

else if(temp1==0 && temp2==0 && temp3==1 &&
temp4==0)

{
// your statements
}

else if(temp1==0 && temp2==1 && temp3==1 &&
temp4==0)

{
// your statements

}
else if(temp1==0 && temp2==0 && temp3==0 &&
temp4==1)

{

// your statements

}
else if(temp1==1 && temp2==0 && temp3==1 &&
temp4==0)
{

// your statements

}
}