ECE 4180 Lab 3 Part 1 Extra Credit
Dependencies: HC_SR04_Ultrasonic_Library mbed
Fork of LPC1768_HCSR04_HelloWorld by
main.cpp@3:3ee23d961329, 2018-10-16 (annotated)
- Committer:
- abraha2d
- Date:
- Tue Oct 16 00:23:27 2018 +0000
- Revision:
- 3:3ee23d961329
- Parent:
- 2:3566c2d1e86b
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Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
abraha2d | 3:3ee23d961329 | 1 | //Theremin style demo using HC-SR04 Sonar and a speaker |
abraha2d | 3:3ee23d961329 | 2 | // moving a hand away/towards sonar changes audio frequency |
ejteb | 0:1704ea055c4f | 3 | #include "mbed.h" |
ejteb | 0:1704ea055c4f | 4 | #include "ultrasonic.h" |
abraha2d | 3:3ee23d961329 | 5 | |
abraha2d | 3:3ee23d961329 | 6 | DigitalOut audio(p26); //output to speaker amp or audio jack |
abraha2d | 3:3ee23d961329 | 7 | DigitalOut led(LED1); |
abraha2d | 3:3ee23d961329 | 8 | DigitalOut led2(LED2); |
abraha2d | 3:3ee23d961329 | 9 | |
abraha2d | 3:3ee23d961329 | 10 | Timeout cycle; |
abraha2d | 3:3ee23d961329 | 11 | |
abraha2d | 3:3ee23d961329 | 12 | volatile int half_cycle_time = 1; |
abraha2d | 3:3ee23d961329 | 13 | |
abraha2d | 3:3ee23d961329 | 14 | //two calls to this interrupt routine generates a square wave |
abraha2d | 3:3ee23d961329 | 15 | void toggle_interrupt() |
ejteb | 0:1704ea055c4f | 16 | { |
abraha2d | 3:3ee23d961329 | 17 | if (half_cycle_time>22000) audio=0; //mute if nothing in range |
abraha2d | 3:3ee23d961329 | 18 | else audio = !audio; //toggle to make half a square wave |
abraha2d | 3:3ee23d961329 | 19 | led = !led; |
abraha2d | 3:3ee23d961329 | 20 | cycle.detach(); |
abraha2d | 3:3ee23d961329 | 21 | //update time for interrupt activation -change frequency of square wave |
abraha2d | 3:3ee23d961329 | 22 | cycle.attach_us(&toggle_interrupt, half_cycle_time); |
ejteb | 0:1704ea055c4f | 23 | } |
abraha2d | 3:3ee23d961329 | 24 | void newdist(int distance) |
abraha2d | 3:3ee23d961329 | 25 | { |
abraha2d | 3:3ee23d961329 | 26 | //update frequency based on new sonar data |
abraha2d | 3:3ee23d961329 | 27 | led2 = !led2; |
abraha2d | 3:3ee23d961329 | 28 | half_cycle_time = distance<<3; |
abraha2d | 3:3ee23d961329 | 29 | } |
abraha2d | 3:3ee23d961329 | 30 | //HC-SR04 Sonar module |
abraha2d | 3:3ee23d961329 | 31 | ultrasonic mu(p6, p7, .07, 1, &newdist); |
abraha2d | 3:3ee23d961329 | 32 | //Set the trigger pin to p6 and the echo pin to p7 |
abraha2d | 3:3ee23d961329 | 33 | //have updates every .07 seconds and a timeout after 1 |
abraha2d | 3:3ee23d961329 | 34 | //second, and call newdist when the distance changes |
abraha2d | 3:3ee23d961329 | 35 | |
ejteb | 0:1704ea055c4f | 36 | int main() |
ejteb | 0:1704ea055c4f | 37 | { |
abraha2d | 3:3ee23d961329 | 38 | audio = 0; |
abraha2d | 3:3ee23d961329 | 39 | led = 0; |
abraha2d | 3:3ee23d961329 | 40 | cycle.attach(&toggle_interrupt, half_cycle_time); |
abraha2d | 3:3ee23d961329 | 41 | mu.startUpdates();//start measuring the distance with the sonar |
abraha2d | 3:3ee23d961329 | 42 | while(1) { |
ejteb | 1:4a5586eb1765 | 43 | //Do something else here |
abraha2d | 3:3ee23d961329 | 44 | mu.checkDistance(); |
abraha2d | 3:3ee23d961329 | 45 | //call checkDistance() as much as possible, as this is where |
abraha2d | 3:3ee23d961329 | 46 | //the class checks if dist needs to be called. |
ejteb | 0:1704ea055c4f | 47 | } |
ejteb | 0:1704ea055c4f | 48 | } |