Diff: main.cpp

Revision:

0:41c4dd155646

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Tue Mar 13 01:08:36 2018 +0000
@@ -0,0 +1,62 @@
+/*----------------------------------------------------------------------------
+LAB EXERCISE 9 - Analog input and PWM
+ ----------------------------------------
+	Use two potentiometers to adjust the volume and pitch of the output sound wave.
+	
+	Inputs: Virtual potentiometers 1 and 2
+	Output: Virtual speaker,  Real PC
+
+	GOOD LUCK!
+ *----------------------------------------------------------------------------*/
+
+#include "mbed.h"
+
+
+/*
+Define the PWM speaker output
+Define analog inputs
+Define serial output
+*/
+#define POT1 (PA_0)			// Analog input for potentiomenter 1: volume 
+#define POT2 (PA_1)			// Analog input for potentiometer 2: pitch
+#define PWM_SPEAKER (PB_10)		// output pin connected to speaker
+
+float constant1 = 0.003;		// within range 320Hz to 8kHz
+float constant2 = 0.000125;
+
+AnalogIn pot1(POT1);			//Create an AnalogIn , connected to the specified pin
+AnalogIn pot2(POT2);
+
+float pot1_value;			// To read values from potentiometers
+float pot2_value;
+
+PwmOut speaker(PWM_SPEAKER);
+Serial serial_output(USBTX, USBRX);
+/*----------------------------------------------------------------------------
+ MAIN function
+ *----------------------------------------------------------------------------*/
+    
+int main() 
+{
+    
+    double i = 0;
+    while(1)
+    {
+	// Read values from the potentiometers
+        pot1_value = pot1.read();
+        pot2_value = pot2.read();
+        printf("\n\r%f %f",pot1_value, pot2_value);			// Print potentiometer values
+        wait(0.5);
+        
+        for(i=0; i<pot1_value; i+=0.05)					// adjusting the PWM steps. s
+        {
+            speaker = i;
+            speaker.period(constant1*pot2_value + constant2);		// variations in pitch is given to output
+        }
+        speaker.write(pot1_value);					// volume output given to speaker
+        
+    }
+}
+// *******************************ARM University Program Copyright � ARM Ltd 2014*************************************
+
+