Diff: main.cpp

Revision:

0:0c8930416cda

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sat Mar 06 18:40:19 2021 +0000
@@ -0,0 +1,49 @@
+//Theremin style demo using HC-SR04 Sonar and a speaker
+// moving a hand away/towards sonar changes audio frequency
+#include "mbed.h"
+#include "ultrasonic.h"
+ 
+DigitalOut audio(p26); //output to speaker amp or audio jack
+DigitalOut led(LED1); 
+DigitalOut led2(LED2);
+ 
+Timeout cycle;
+ 
+volatile int half_cycle_time = 1;
+ 
+//two calls to this interrupt routine generates a square wave
+void toggle_interrupt()
+{
+    if (half_cycle_time>22000) audio=0; //mute if nothing in range
+    else audio = !audio; //toggle to make half a square wave
+    led = !led;
+    cycle.detach();
+    //update time for interrupt activation -change frequency of square wave
+    cycle.attach_us(&toggle_interrupt, half_cycle_time);
+}
+void newdist(int distance)
+{
+    //update frequency based on new sonar data
+    led2 = !led2;
+    half_cycle_time = distance<<3;
+}
+//HC-SR04 Sonar module
+ultrasonic mu(p6, p7, .07, 1, &newdist);    
+//Set the trigger pin to p6 and the echo pin to p7
+//have updates every .07 seconds and a timeout after 1
+//second, and call newdist when the distance changes
+ 
+int main()
+{
+    audio = 0;
+    led = 0;
+    cycle.attach(&toggle_interrupt, half_cycle_time);
+    mu.startUpdates();//start measuring the distance with the sonar
+    while(1) {
+        //Do something else here
+        mu.checkDistance();     
+        //call checkDistance() as much as possible, as this is where
+        //the class checks if dist needs to be called.
+    }
+}
+