buzzer: fixed sounds not stopping and added extra functions

Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>

src/buzzer/buzzer.cxx

@@ -28,23 +28,47 @@
 #include "buzzer.h"
 
 using namespace upm;
+using namespace std;
 
-Buzzer::Buzzer (int pinNumber) {
-    m_pwm_context = mraa_pwm_init (pinNumber);
+Buzzer::Buzzer(int pinNumber) {
+    m_pwm_context = mraa_pwm_init(pinNumber);
+    if(m_pwm_context == 0)
+    {
+        cerr << __FUNCTION__ << ": Error initializing PWM on pin " << pinNumber << endl;
+        return;
+    }
     m_name = "Buzzer";
+    mraa_pwm_enable (m_pwm_context, 1);
+    Buzzer::setVolume(1.0);
 }
 
-int Buzzer::playSound (int note, int delay) {
-    mraa_pwm_enable (m_pwm_context, 1);
-    mraa_pwm_period_us (m_pwm_context, note);
-    mraa_pwm_pulsewidth_us (m_pwm_context, note / 2);
-    usleep (delay);
-    mraa_pwm_enable (m_pwm_context, 0);
+void Buzzer::setVolume(float vol){
+    m_volume = vol;
+}
 
+float Buzzer::getVolume(){
+    return m_volume;
+}
+
+int Buzzer::playSound(int note, int delay) {
+    mraa_pwm_period_us(m_pwm_context, note);
+    mraa_pwm_write(m_pwm_context, m_volume * 0.5);
+    if(delay){
+        usleep(delay);
+        Buzzer::stopSound();
+    }
     return note;
 }
 
+void Buzzer::stopSound(){
+    // Has to be checked out on a scope and make sure it's flat 0
+    mraa_pwm_period_us(m_pwm_context, 1);
+    mraa_pwm_write(m_pwm_context, 0);
+}
+
 Buzzer::~Buzzer() {
+    Buzzer::stopSound();
+    mraa_pwm_enable(m_pwm_context, 0);
     mraa_pwm_close(m_pwm_context);
 }
 

src/buzzer/buzzer.h

@@ -54,7 +54,7 @@ namespace upm {
 class Buzzer {
     public:
         /**
-         * Instantiates a Buzzer object
+         * Instantiates a Buzzer object.
          *
          * @param pinNumber Buzzer pin number
          */
@@ -66,17 +66,40 @@ class Buzzer {
         ~Buzzer ();
 
         /**
-         * Play a tone for a certain amount of time.
+         * Play a tone for a certain amount of time or indefinitely. When delay
+         * is not used, the sound can be stopped by calling stopSound().
          *
-         * @param note the note to be played (DO, RE, MI, etc...)
-         * @param delay time in microsec for playing the sound
+         * @param note the note to be played (DO, RE, MI, etc...) or frequency
+         * @param delay time in microseconds for playing the sound, a value of
+         * 0 plays the sound indefinitely
          *
          * @return the note played
          */
         int playSound (int note, int delay);
 
         /**
-         * Return name of the component
+         * Stops the sound currently playing. Has to be called when playSound()
+         * does not set a delay value.
+         */
+        void stopSound();
+
+        /**
+         * Sets the volume for the buzzer, but may affect the sound timbre.
+         * Works best with halved values, e.g. 1.0, 0.5, 0.25, ...
+         *
+         * @param vol the value to set the volume to from 0.0 to 1.0
+         */
+        void setVolume(float vol);
+
+        /**
+         * Gets the buzzer volume.
+         *
+         * @return the value the volume was set to
+         */
+        float getVolume();
+
+        /**
+         * Return name of the component.
          *
          * @return name of the sensor
          */
@@ -88,5 +111,6 @@ class Buzzer {
         std::string m_name;
     private:
         mraa_pwm_context m_pwm_context;
+        float m_volume;
 };
 }