ultrasonic: Created ultrasonic from groveultrasonic.

* Added C++ and javascript example.
    * Added jpg.

Signed-off-by: Noel Eck <noel.eck@intel.com>

src/ultrasonic/ultrasonic.cxx

@@ -0,0 +1,104 @@
+/*
+ * Author: Jun Kato <i@junkato.jp>
+ * Copyright (c) 2015 Jun Kato.
+ *
+ * Thanks to Seeed Studio for a working arduino sketch
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <iostream>
+#include <unistd.h>
+#include <stdlib.h>
+#include <functional>
+
+#include "ultrasonic.hpp"
+
+using namespace upm;
+
+UltraSonic::UltraSonic (uint8_t pin) {
+    mraa_result_t error = MRAA_SUCCESS;
+    m_name = "UltraSonic";
+
+    mraa_init();
+
+    // setup pin
+    m_pinCtx = mraa_gpio_init(pin);
+    if (m_pinCtx == NULL) {
+        fprintf (stderr, "Are you sure that pin%d you requested is valid on your platform?", pin);
+        exit (1);
+    }
+    mraa_gpio_use_mmaped(m_pinCtx, 1);
+    mraa_gpio_isr (m_pinCtx, MRAA_GPIO_EDGE_BOTH,
+                   &signalISR, this);
+}
+
+UltraSonic::~UltraSonic () {
+
+    // close pin
+    mraa_gpio_isr_exit(m_pinCtx);
+    mraa_gpio_close (m_pinCtx);
+}
+
+int
+UltraSonic::getDistance () {
+
+    // output trigger signal
+    mraa_gpio_dir(m_pinCtx, MRAA_GPIO_OUT);
+    mraa_gpio_write(m_pinCtx, LOW);
+    usleep(2);
+    mraa_gpio_write(m_pinCtx, HIGH);
+    usleep(5);
+    mraa_gpio_write(m_pinCtx, LOW);
+
+    // wait for the pulse,
+    m_doWork = true;
+    m_InterruptCounter = 0;
+    mraa_gpio_dir(m_pinCtx, MRAA_GPIO_IN);
+
+    // though do not wait over 25 [ms].
+    int timer = 0;
+    while (m_doWork && timer++ < 5) {
+        // in 25 [ms], sound travels 25000 / 29 / 2 = 431 [cm],
+        // which is more than 400 [cm], the max distance measurable with this sensor.
+        usleep(5 * 1000); // 5 [ms]
+    }
+
+    // calc diff
+    long diff = m_FallingTimeStamp.tv_usec - m_RisingTimeStamp.tv_usec;
+    diff += (m_FallingTimeStamp.tv_sec - m_RisingTimeStamp.tv_sec) * 1000000;
+    return timer >= 5 ? 0 : diff;
+}
+
+void
+UltraSonic::signalISR(void *ctx) {
+    upm::UltraSonic *This = (upm::UltraSonic *)ctx;
+    This->ackEdgeDetected();
+}
+
+void
+UltraSonic::ackEdgeDetected () {
+    if (++m_InterruptCounter % 2 == 0) {
+        gettimeofday(&m_FallingTimeStamp, NULL);
+        m_doWork = false;
+    } else {
+        gettimeofday(&m_RisingTimeStamp, NULL);
+    }
+}