HamShield/examples/DTMF/DTMF.ino

/* Hamshield
 * Example: DTMF
 * This is a simple example to demonstrate how to ues DTMF.
 *
 * Connect the HamShield to your Arduino. Screw the antenna 
 * into the HamShield RF jack. 
 * Connect the Arduino to wall power and then to your computer
 * via USB. After uploading this program to your Arduino, open
 * the Serial Monitor. Press the button on the HamShield to 
 * begin setup. After setup is complete, type in a DTMF value
 * (0-9, A, B, C, D, *, #) and hit enter. The corresponding
 * DTMF tones will be transmitted. The sketch will also print
 * any received DTMF tones to the screen.
**/

#include <HamShield.h>

// create object for radio
HamShield radio;

#define LED_PIN 13

#define PWM_PIN 3
#define RESET_PIN A3
#define SWITCH_PIN 2

uint32_t freq;

void setup() {
  // NOTE: if not using PWM out, it should be held low to avoid tx noise
  pinMode(PWM_PIN, OUTPUT);
  digitalWrite(PWM_PIN, LOW);
  
  // prep the switch
  pinMode(SWITCH_PIN, INPUT_PULLUP);
  
  // set up the reset control pin
  pinMode(RESET_PIN, OUTPUT);
  digitalWrite(RESET_PIN, LOW);
  
  
  // initialize serial communication
  Serial.begin(9600);
  Serial.println("press the switch to begin...");
  
  while (digitalRead(SWITCH_PIN));
  
  // let the AU ot of reset
  digitalWrite(RESET_PIN, HIGH);
  
  Serial.println("beginning radio setup");

  // verify connection
  Serial.println("Testing device connections...");
  Serial.println(radio.testConnection() ? "HamShield connection successful" : "HamShield connection failed");

  // initialize device
  radio.initialize(); // initializes automatically for UHF 12.5kHz channel

  Serial.println("setting default Radio configuration");

  Serial.println("setting squelch");

  radio.setSQHiThresh(-10);
  radio.setSQLoThresh(-30);
  Serial.print("sq hi: ");
  Serial.println(radio.getSQHiThresh());
  Serial.print("sq lo: ");
  Serial.println(radio.getSQLoThresh());
  radio.setSQOn();
  //radio.setSQOff();

  Serial.println("changing frequency");
  freq = 420000;
  radio.frequency(freq);
  
  // set RX volume to minimum to reduce false positives on DTMF rx
  radio.setVolume1(6);
  radio.setVolume2(0);
  
  // set to receive
  radio.setModeReceive();
  
  radio.setRfPower(0);
    
  // configure Arduino LED for
  pinMode(LED_PIN, OUTPUT);

  // set up DTMF
  radio.enableDTMFReceive();
  Serial.println("ready");
}

char rx_dtmf_buf[255];
int  rx_dtmf_idx = 0;
void loop() {
  
  // look for tone
  if (radio.getDTMFSample() != 0) {
    uint16_t code = radio.getDTMFCode();

    rx_dtmf_buf[rx_dtmf_idx++] = code2char(code);

    // reset after this tone
    int j = 0;
    while (j < 4) {
      if (radio.getDTMFSample() == 0) {
        j++;
      }
      delay(10);
    }
  } else if (rx_dtmf_idx > 0) {
    rx_dtmf_buf[rx_dtmf_idx] = '\0'; // NULL terminate the string
    Serial.println(rx_dtmf_buf);
    rx_dtmf_idx = 0;
  }
  
  // Is it time to send tone?
  if (Serial.available()) {
    uint8_t code = char2code(Serial.read());
    
    // start transmitting
    radio.setDTMFCode(code); // set first
    radio.setTxSourceTones();
    radio.setModeTransmit();
    delay(300); // wait for TX to come to full power

    bool dtmf_to_tx = true;
    while (dtmf_to_tx) {
      // wait until ready
      while (radio.getDTMFTxActive() != 1) {
        // wait until we're ready for a new code
        delay(10);
      }
      while (radio.getDTMFTxActive() != 0) {
        // wait until this code is done
        delay(10);
      }

      if (Serial.available()) {
        code = char2code(Serial.read());
        radio.setDTMFCode(code); // set first
      } else {
        dtmf_to_tx = false;
      }
    }
    // done with tone
    radio.setModeReceive();
    radio.setTxSourceMic();
  }
}

uint8_t char2code(char c) {
    uint8_t code;
    if (c == '#') {
      code = 0xF;
    } else if (c=='*') {
      code = 0xE;
    } else if (c >= 'A' && c <= 'D') {
      code = c - 'A' + 0xA;
    } else if (c >= '0' && c <= '9') {
      code = c - '0';
    } else {
      // invalid code, skip it
      code = 255;
    }

    return code;
}

char code2char(uint16_t code) {
  char c;
  if (code < 10) {
    c = '0' + code;
  } else if (code < 0xE) {
    c = 'A' + code - 10;
  } else if (code == 0xE) {
    c = '*';
  } else if (code == 0xF) {
    c = '#';
  } else {
    c = '?'; // invalid code
  }
 
  return c;
}