Jack Snape / HC-SR04

basic class for the use of the HC-SR04 ultrasound sensor

Dependents:   mazeSolver

HC-SR04.cpp@0:b4a6f6bcab30, 2021-10-31 (annotated)

Committer:
snapo
Date:
Sun Oct 31 10:46:33 2021 +0000
Revision:
0:b4a6f6bcab30
basic class for use of the HC-SR04 ultrasound sensor

Who changed what in which revision?

UserRevisionLine numberNew contents of line
snapo 0:b4a6f6bcab30 1 #include "HC-SR04.h"
snapo 0:b4a6f6bcab30 2
snapo 0:b4a6f6bcab30 3
snapo 0:b4a6f6bcab30 4
snapo 0:b4a6f6bcab30 5 HCSR04::HCSR04 (PinName echo, PinName trigger):
snapo 0:b4a6f6bcab30 6 echo_(echo), trigger_(trigger, PIN_OUTPUT, OpenDrain, 0){};
snapo 0:b4a6f6bcab30 7
snapo 0:b4a6f6bcab30 8 void HCSR04::reading(){
snapo 0:b4a6f6bcab30 9 t_.reset();
snapo 0:b4a6f6bcab30 10
snapo 0:b4a6f6bcab30 11 trigger_ = true;
snapo 0:b4a6f6bcab30 12 wait_us(10);
snapo 0:b4a6f6bcab30 13 trigger_ = false;
snapo 0:b4a6f6bcab30 14
snapo 0:b4a6f6bcab30 15 //waits for the echo pin to activate then starts to measure time
snapo 0:b4a6f6bcab30 16 while(!echo_);
snapo 0:b4a6f6bcab30 17 t_.start();
snapo 0:b4a6f6bcab30 18 while(echo_);
snapo 0:b4a6f6bcab30 19 //time stops being measured once echo is deactivated.
snapo 0:b4a6f6bcab30 20 t_.stop();
snapo 0:b4a6f6bcab30 21 //time measured in microseconds to increase the accuracy then the distance is scaled up into mm.
snapo 0:b4a6f6bcab30 22 time_us_ = duration_cast<std::chrono::microseconds>(t_.elapsed_time()).count();
snapo 0:b4a6f6bcab30 23 //distance stored in baseDistance_ variable
snapo 0:b4a6f6bcab30 24 distance_ = (160*time_us_) / 1000;
snapo 0:b4a6f6bcab30 25 thread_sleep_for(1000);
snapo 0:b4a6f6bcab30 26 }
snapo 0:b4a6f6bcab30 27
snapo 0:b4a6f6bcab30 28 void HCSR04::fastTimeReading(){
snapo 0:b4a6f6bcab30 29 t_.reset();
snapo 0:b4a6f6bcab30 30
snapo 0:b4a6f6bcab30 31 trigger_ = true;
snapo 0:b4a6f6bcab30 32 wait_us(10);
snapo 0:b4a6f6bcab30 33 trigger_ = false;
snapo 0:b4a6f6bcab30 34
snapo 0:b4a6f6bcab30 35 //waits for the echo pin to activate then starts to measure time
snapo 0:b4a6f6bcab30 36 while(!echo_);
snapo 0:b4a6f6bcab30 37 t_.start();
snapo 0:b4a6f6bcab30 38 while(echo_);
snapo 0:b4a6f6bcab30 39 //time stops being measured once echo is deactivated.
snapo 0:b4a6f6bcab30 40 t_.stop();
snapo 0:b4a6f6bcab30 41 time_us_ = duration_cast<std::chrono::microseconds>(t_.elapsed_time()).count();
snapo 0:b4a6f6bcab30 42
snapo 0:b4a6f6bcab30 43 }
snapo 0:b4a6f6bcab30 44
snapo 0:b4a6f6bcab30 45 int HCSR04::getTime(){
snapo 0:b4a6f6bcab30 46 return time_us_;
snapo 0:b4a6f6bcab30 47 }
snapo 0:b4a6f6bcab30 48
snapo 0:b4a6f6bcab30 49 int HCSR04::getDistance(){
snapo 0:b4a6f6bcab30 50 return distance_;
snapo 0:b4a6f6bcab30 51 }
snapo 0:b4a6f6bcab30 52