Diff: HCSR04/HCSR04.cpp

Revision:

0:e7c4d23dbc05

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/HCSR04/HCSR04.cpp	Thu Sep 28 03:44:12 2017 +0000
@@ -0,0 +1,81 @@
+#include "mbed.h"
+#include "HCSR04.h"
+
+HCSR04::HCSR04(PinName echoPin, PinName triggerPin) : echo(echoPin), trigger(triggerPin) {
+    init();
+}
+
+void HCSR04::init() {
+    distance = -1;      // initial distance
+    minDistance = 2;
+    maxDistance = 400;
+    newDataReady = timerStarted = false;
+}
+
+void HCSR04::startTimer() {
+    if (!timerStarted) {
+        timer.start(); // start the timer
+        timerStarted = true;
+        echoTimeout.attach_us(this, &HCSR04::stopTimer, 25000); // in case echo fall does not occur
+        echo.fall(this, &HCSR04::stopTimer);
+        echo.rise(NULL);
+    }
+}
+
+void HCSR04::stopTimer() {
+    timer.stop(); // stop the timer
+    if (timerStarted) {
+        distance = timer.read() * 1e6 / 58;
+        if (distance < minDistance)
+            distance = minDistance;
+        if (distance > maxDistance)
+            distance = maxDistance;
+        newDataReady = true;
+    }
+    timer.reset();
+    timerStarted = false;
+    echoTimeout.detach();
+    echo.fall(NULL);
+}
+
+void HCSR04::turnOffTrigger() {
+    trigger = 0; 
+}
+
+void HCSR04::startMeasurement() {
+    trigger = 1;
+    triggerTimeout.attach_us(this, &HCSR04::turnOffTrigger, 10);
+    echo.rise(this, &HCSR04::startTimer);
+    newDataReady = false;
+}
+
+float HCSR04::getDistance_cm() {
+    newDataReady = false;
+    return distance;
+}
+
+float HCSR04::getDistance_mm() {
+    newDataReady = false;
+    return distance * 10;
+}
+
+bool HCSR04::isNewDataReady() {
+    return newDataReady;
+}
+
+void HCSR04::setRanges(float minRange, float maxRange) {
+    if (minRange < maxRange) {
+        if (minRange >= 2 && minRange < 400) // bug from revs. 4 and 5 corrected
+            minDistance = minRange;
+        if (maxRange <= 400)
+            maxDistance = maxRange;
+    }
+}
+
+float HCSR04::getMinRange() {
+    return minDistance;
+}
+
+float HCSR04::getMaxRange() {
+    return maxDistance;
+}
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