I-Sheng Tseng / Mbed OS IoT_Final_Project_v2

project

Dependencies:   MbedJSONValue DISCO_L475VG_IOT01A_wifi mbed-http

Diff: US100.cpp

Revision:
0:8bcd728684c5
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/US100.cpp	Mon Jan 07 11:19:49 2019 +0000
@@ -0,0 +1,29 @@
+#include "US100.h"
+#include "mbed.h"
+US100::US100(PinName t, PinName e) : trig(t), echo(e) {}
+// Trigger Echo
+// ______ _____________,,,,,,,,,
+// ____| 10us |_________| 150us-25ms, or 38ms if no obstacle
+//
+//return echo duration in us (refer to digram above)
+int US100::echo_duration()
+{
+    timer.reset();
+    trig = 0;
+    wait_us(10);
+    trig = 1;
+    wait_us(10);
+    trig = 0;
+    while(echo == 0);
+    timer.start();
+    while(echo == 1);
+    timer.stop();
+    return timer.read_us();
+}
+
+int US100::distance()
+{
+int duration = echo_duration();
+int distacne_mm = duration*0.34/2/10;
+return distacne_mm;
+}
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