Weber Yang / Mbed 2 deprecated mbed_sonar

Delta for AGV

Dependencies:   mbed HC-SR04 ros_lib_kinetic

main.cpp@0:ebee649c5b1b, 2015-12-03 (annotated)

Committer:
tbjazic
Date:
Thu Dec 03 15:43:54 2015 +0000
Revision:
0:ebee649c5b1b
Child:
1:22043b67c31c
Revision 1: Solution in the main program, without class.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
tbjazic 0:ebee649c5b1b 1 /** Initial test of the ultrasonic sensor HC-SR04 */
tbjazic 0:ebee649c5b1b 2
tbjazic 0:ebee649c5b1b 3 #include "mbed.h"
tbjazic 0:ebee649c5b1b 4
tbjazic 0:ebee649c5b1b 5 Serial pc(USBTX, USBRX); // communication with terminal
tbjazic 0:ebee649c5b1b 6 InterruptIn echo(p5); // echo pin
tbjazic 0:ebee649c5b1b 7 DigitalOut trigger(p7); // trigger pin
tbjazic 0:ebee649c5b1b 8 Timer timer; // echo pulsewidth measurement
tbjazic 0:ebee649c5b1b 9
tbjazic 0:ebee649c5b1b 10 /** Start the echo pulsewidth measurement */
tbjazic 0:ebee649c5b1b 11 void startTimer() {
tbjazic 0:ebee649c5b1b 12 timer.start(); // start the timer
tbjazic 0:ebee649c5b1b 13 }
tbjazic 0:ebee649c5b1b 14
tbjazic 0:ebee649c5b1b 15 /** Stop the echo pulsewidth measurement */
tbjazic 0:ebee649c5b1b 16 void stopTimer() {
tbjazic 0:ebee649c5b1b 17 timer.stop(); // stop the timer
tbjazic 0:ebee649c5b1b 18 }
tbjazic 0:ebee649c5b1b 19
tbjazic 0:ebee649c5b1b 20 int main() {
tbjazic 0:ebee649c5b1b 21 /** configure the rising edge to start the timer */
tbjazic 0:ebee649c5b1b 22 echo.rise(&startTimer);
tbjazic 0:ebee649c5b1b 23
tbjazic 0:ebee649c5b1b 24 /** configure the falling edge to stop the timer */
tbjazic 0:ebee649c5b1b 25 echo.fall(&stopTimer);
tbjazic 0:ebee649c5b1b 26
tbjazic 0:ebee649c5b1b 27 while(1) {
tbjazic 0:ebee649c5b1b 28 /** Start the measurement by sending the 10us trigger pulse */
tbjazic 0:ebee649c5b1b 29 trigger = 1;
tbjazic 0:ebee649c5b1b 30 wait_us(10);
tbjazic 0:ebee649c5b1b 31 trigger = 0;
tbjazic 0:ebee649c5b1b 32
tbjazic 0:ebee649c5b1b 33 /** Wait for the sensor to finish measurement (generate rise and fall interrupts).
tbjazic 0:ebee649c5b1b 34 * Minimum wait time is determined by maximum measurement distance of 400 cm.
tbjazic 0:ebee649c5b1b 35 * t_min = 400 * 58 = 23200 us = 23.2 ms */
tbjazic 0:ebee649c5b1b 36 wait(1);
tbjazic 0:ebee649c5b1b 37
tbjazic 0:ebee649c5b1b 38 /** calculate the distance in cm */
tbjazic 0:ebee649c5b1b 39 float distance = timer.read() * 1e6 / 58;
tbjazic 0:ebee649c5b1b 40 timer.reset(); // reset the timer to 0
tbjazic 0:ebee649c5b1b 41
tbjazic 0:ebee649c5b1b 42 /** Print the result in cm to the terminal with 1 decimal place
tbjazic 0:ebee649c5b1b 43 * (number 5 after % means that total of 5 digits will be reserved
tbjazic 0:ebee649c5b1b 44 * for printing the number, including the dot and one decimal place). */
tbjazic 0:ebee649c5b1b 45 pc.printf("Distance: %5.1f cm\r", distance);
tbjazic 0:ebee649c5b1b 46 }
tbjazic 0:ebee649c5b1b 47 }