TVZ Mechatronics Team / HCSR04

A distance measurement class using ultrasonic sensor HC-SR04.

Dependents:   Esercitazione4_4 HC-SR04 Group10_slave Oled_Gus ... more

The purpose of this library is to encourage students to develope their own classes. Instructions how to follow the development of this library for ultrasonic distance measurement are given here.

HCSR04.h@5:a667b621f625, 2015-12-07 (annotated)

Committer:
tbjazic
Date:
Mon Dec 07 09:57:48 2015 +0000
Revision:
5:a667b621f625
Parent:
4:aae70f15357f
Child:
6:cf3e4e307d15
Example of use (documentation part) updated.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
tbjazic 0:8871082486ac 1 #ifndef HCSR04_H_TVZMT
tbjazic 0:8871082486ac 2 #define HCSR04_H_TVZMT
tbjazic 0:8871082486ac 3
tbjazic 0:8871082486ac 4 /** A distance measurement class using ultrasonic sensor HC-SR04.
tbjazic 0:8871082486ac 5 *
tbjazic 0:8871082486ac 6 * Example of use:
tbjazic 2:aa59a9c531be 7 * @code
tbjazic 0:8871082486ac 8 * #include "mbed.h"
tbjazic 0:8871082486ac 9 * #include "HCSR04.h"
tbjazic 0:8871082486ac 10 *
tbjazic 5:a667b621f625 11 * Serial pc(USBTX, USBRX);
tbjazic 5:a667b621f625 12 *
tbjazic 0:8871082486ac 13 * int main() {
tbjazic 5:a667b621f625 14 * HCSR04 sensor(p5, p7);
tbjazic 5:a667b621f625 15 * sensor.setRanges(10, 110);
tbjazic 5:a667b621f625 16 * pc.printf("Min. range = %g cm\n\rMax. range = %g cm\n\r",
tbjazic 5:a667b621f625 17 * sensor.getMinRange(), sensor.getMaxRange());
tbjazic 0:8871082486ac 18 * while(1) {
tbjazic 5:a667b621f625 19 * pc.printf("Distance: %5.1f mm\r", sensor.getDistance_mm());
tbjazic 5:a667b621f625 20 * wait_ms(500);
tbjazic 0:8871082486ac 21 * }
tbjazic 0:8871082486ac 22 * }
tbjazic 2:aa59a9c531be 23 * @endcode
tbjazic 0:8871082486ac 24 */
tbjazic 0:8871082486ac 25 class HCSR04 {
tbjazic 0:8871082486ac 26
tbjazic 0:8871082486ac 27 public:
tbjazic 0:8871082486ac 28
tbjazic 0:8871082486ac 29 /** Receives two PinName variables.
tbjazic 0:8871082486ac 30 * @param echoPin mbed pin to which the echo signal is connected to
tbjazic 0:8871082486ac 31 * @param triggerPin mbed pin to which the trigger signal is connected to
tbjazic 0:8871082486ac 32 */
tbjazic 0:8871082486ac 33 HCSR04(PinName echoPin, PinName triggerPin);
tbjazic 0:8871082486ac 34
tbjazic 4:aae70f15357f 35 /** Calculates the distance in cm, with the calculation time of approximatelly 23.7 ms.
tbjazic 0:8871082486ac 36 * @returns distance of the measuring object in cm.
tbjazic 0:8871082486ac 37 */
tbjazic 0:8871082486ac 38 float getDistance_cm();
tbjazic 0:8871082486ac 39
tbjazic 4:aae70f15357f 40 /** Calculates the distance in mm, with the calculation time of approximatelly 23.7 ms.
tbjazic 4:aae70f15357f 41 * @returns distance of the measuring object in mm.
tbjazic 4:aae70f15357f 42 */
tbjazic 4:aae70f15357f 43 float getDistance_mm();
tbjazic 4:aae70f15357f 44
tbjazic 4:aae70f15357f 45 /** Sets the minimum and maximum ranges between the factory values of 2 cm and 400 cm.
tbjazic 4:aae70f15357f 46 * @param minRange Minimum range in cm. Must be between 2 cm and maxRange.
tbjazic 4:aae70f15357f 47 * @param maxRange Maximum range in cm. Must be between minRange and 400 cm.
tbjazic 4:aae70f15357f 48 */
tbjazic 4:aae70f15357f 49 void setRanges(float minRange, float maxRange);
tbjazic 4:aae70f15357f 50
tbjazic 4:aae70f15357f 51 /** Retreives the minimum sensor range set by the user.
tbjazic 4:aae70f15357f 52 * @returns the minimum sensor range set by the user in cm.
tbjazic 4:aae70f15357f 53 */
tbjazic 4:aae70f15357f 54 float getMinRange();
tbjazic 4:aae70f15357f 55
tbjazic 4:aae70f15357f 56 /** Retreives the maximum sensor range set by the user.
tbjazic 4:aae70f15357f 57 * @returns the maximum sensor range set by the user in cm.
tbjazic 4:aae70f15357f 58 */
tbjazic 4:aae70f15357f 59 float getMaxRange();
tbjazic 4:aae70f15357f 60
tbjazic 0:8871082486ac 61 private:
tbjazic 0:8871082486ac 62
tbjazic 0:8871082486ac 63 InterruptIn echo; // echo pin
tbjazic 0:8871082486ac 64 DigitalOut trigger; // trigger pin
tbjazic 0:8871082486ac 65 Timer timer; // echo pulsewidth measurement
tbjazic 0:8871082486ac 66 float distance; // store the distance in cm
tbjazic 3:9a7899cf5e3a 67 float minDistance; // minimum measurable distance
tbjazic 3:9a7899cf5e3a 68 float maxDistance; // maximum measurable distance
tbjazic 0:8871082486ac 69
tbjazic 0:8871082486ac 70 /** Start the timer. */
tbjazic 0:8871082486ac 71 void startTimer();
tbjazic 0:8871082486ac 72
tbjazic 0:8871082486ac 73 /** Stop the timer. */
tbjazic 0:8871082486ac 74 void stopTimer();
tbjazic 0:8871082486ac 75
tbjazic 0:8871082486ac 76 /** Initialization. */
tbjazic 0:8871082486ac 77 void init();
tbjazic 0:8871082486ac 78
tbjazic 0:8871082486ac 79 /** Start the measurement. */
tbjazic 0:8871082486ac 80 void startMeasurement();
tbjazic 0:8871082486ac 81 };
tbjazic 0:8871082486ac 82
tbjazic 0:8871082486ac 83 #endif