ECE 4180 Lab 3 Part 1 Extra Credit
Dependencies: HC_SR04_Ultrasonic_Library mbed
Fork of LPC1768_HCSR04_HelloWorld by
main.cpp
- Committer:
- abraha2d
- Date:
- 2018-10-16
- Revision:
- 3:3ee23d961329
- Parent:
- 2:3566c2d1e86b
File content as of revision 3:3ee23d961329:
//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. } }