Add DTMF Dial Tone decode + transmit example

examples/DialTone_DTMF/DialTone_DTMF.ino

+#include <Audio.h>
+#include <Wire.h>
+#include <SD.h>
+
+// Create the Audio components.  These should be created in the
+// order data flows, inputs/sources -> processing -> outputs
+//
+AudioInputI2S            audioIn;
+AudioAnalyzeToneDetect   row1;     // 7 tone detectors are needed
+AudioAnalyzeToneDetect   row2;     // to receive DTMF dial tones
+AudioAnalyzeToneDetect   row3;
+AudioAnalyzeToneDetect   row4;
+AudioAnalyzeToneDetect   column1;
+AudioAnalyzeToneDetect   column2;
+AudioAnalyzeToneDetect   column3;
+AudioSynthWaveform       sine1(AudioWaveformSine);  // 2 sine wave
+AudioSynthWaveform       sine2(AudioWaveformSine);  // to create DTMF
+AudioMixer4              mixer;
+AudioOutputI2S           audioOut;
+
+// Create Audio connections between the components
+//
+AudioConnection c01(audioIn, 0, row1, 0);
+AudioConnection c02(audioIn, 0, row2, 0);
+AudioConnection c03(audioIn, 0, row3, 0);
+AudioConnection c04(audioIn, 0, row4, 0);
+AudioConnection c05(audioIn, 0, column1, 0);
+AudioConnection c06(audioIn, 0, column2, 0);
+AudioConnection c07(audioIn, 0, column3, 0);
+AudioConnection c10(sine1, 0, mixer, 0);
+AudioConnection c11(sine2, 0, mixer, 1);
+AudioConnection c12(mixer, 0, audioOut, 0);
+AudioConnection c13(mixer, 0, audioOut, 1);
+
+// Create an object to control the audio shield.
+// 
+AudioControlSGTL5000 audioShield;
+
+
+void setup() {
+  // Audio connections require memory to work.  For more
+  // detailed information, see the MemoryAndCpuUsage example
+  AudioMemory(12);
+
+  // Enable the audio shield and set the output volume.
+  audioShield.enable();
+  audioShield.volume(82);
+  
+  while (!Serial) ;
+  delay(100);
+  
+  // Configure the tone detectors with the frequency and number
+  // of cycles to match.  These numbers were picked for match
+  // times of approx 30 ms.  Longer times are more precise.
+  row1.frequency(697, 21);
+  row2.frequency(770, 23);
+  row3.frequency(852, 25);
+  row4.frequency(941, 28);
+  column1.frequency(1209, 36);
+  column2.frequency(1336, 40);
+  column3.frequency(1477, 44);
+}
+
+const float row_threshold = 0.2;
+const float column_threshold = 0.2;
+
+void loop() {
+  float r1, r2, r3, r4, c1, c2, c3;
+  char digit=0;
+
+  // read all seven tone detectors
+  r1 = row1.read();
+  r2 = row2.read();
+  r3 = row3.read();
+  r4 = row4.read();
+  c1 = column1.read();
+  c2 = column2.read();
+  c3 = column3.read();
+
+  // print the raw data, for troubleshooting
+  Serial.print("tones: ");
+  Serial.print(r1);
+  Serial.print(", ");
+  Serial.print(r2);
+  Serial.print(", ");
+  Serial.print(r3);
+  Serial.print(", ");
+  Serial.print(r4);
+  Serial.print(",   ");
+  Serial.print(c1);
+  Serial.print(", ");
+  Serial.print(c2);
+  Serial.print(", ");
+  Serial.print(c3);
+
+  // check all 12 combinations for key press
+  if (r1 >= row_threshold) {
+    if (c1 > column_threshold) {
+      digit = '1';
+    } else if (c2 > column_threshold) {
+      digit = '2';
+    } else if (c3 > column_threshold) {
+      digit = '3';
+    }
+  } else if (r2 >= row_threshold) { 
+    if (c1 > column_threshold) {
+      digit = '4';
+    } else if (c2 > column_threshold) {
+      digit = '5';
+    } else if (c3 > column_threshold) {
+      digit = '6';
+    }
+  } else if (r3 >= row_threshold) { 
+    if (c1 > column_threshold) {
+      digit = '7';
+    } else if (c2 > column_threshold) {
+      digit = '8';
+    } else if (c3 > column_threshold) {
+      digit = '9';
+    }
+  } else if (r4 >= row_threshold) { 
+    if (c1 > column_threshold) {
+      digit = '*';
+    } else if (c2 > column_threshold) {
+      digit = '0';
+    } else if (c3 > column_threshold) {
+      digit = '#';
+    }
+  }
+
+  // print the key, if any found
+  if (digit > 0) {
+    Serial.print("  --> Key: ");
+    Serial.print(digit);
+  }
+  Serial.println();
+
+  // uncomment these lines to see how much CPU time
+  // the tone detectors and audio library are using
+  //Serial.print("CPU=");
+  //Serial.print(AudioProcessorUsage());
+  //Serial.print("%, max=");
+  //Serial.print(AudioProcessorUsageMax());
+  //Serial.print("%   ");
+
+  // check if any data has arrived from the serial monitor
+  if (Serial.available()) {
+    char key = Serial.read();
+    int low=0;
+    int high=0;
+    if (key == '1') {
+      low = 697;
+      high = 1209;
+    } else if (key == '2') {
+      low = 697;
+      high = 1336;
+    } else if (key == '3') {
+      low = 697;
+      high = 1477;
+    } else if (key == '4') {
+      low = 770;
+      high = 1209;
+    } else if (key == '5') {
+      low = 770;
+      high = 1336;
+    } else if (key == '6') {
+      low = 770;
+      high = 1477;
+    } else if (key == '7') {
+      low = 852;
+      high = 1209;
+    } else if (key == '8') {
+      low = 852;
+      high = 1336;
+    } else if (key == '9') {
+      low = 852;
+      high = 1477;
+    } else if (key == '*') {
+      low = 941;
+      high = 1209;
+    } else if (key == '0') {
+      low = 941;
+      high = 1336;
+    } else if (key == '#') {
+      low = 941;
+      high = 1477;
+    }
+
+    // play the DTMF tones, if characters send from the Arduino Serial Monitor
+    if (low > 0 && high > 0) {
+      Serial.print("Output sound for key ");
+      Serial.print(key);
+      Serial.print(", low freq=");
+      Serial.print(low);
+      Serial.print(", high freq=");
+      Serial.print(high);
+      Serial.println();
+      AudioNoInterrupts();  // disable audio library momentarily
+      sine1.frequency(low);
+      sine1.amplitude(0.4);
+      sine2.frequency(high);
+      sine2.amplitude(0.45);
+      AudioInterrupts();    // enable, both tones will start together
+      delay(100);           // let the sound play for 0.1 second
+      AudioNoInterrupts();
+      sine1.amplitude(0);
+      sine2.amplitude(0);
+      AudioInterrupts();
+      delay(50);            // make sure we have 0.05 second silence after
+    }
+  }
+
+  delay(25);
+}
+
+