bh1750: Initial implementation

This driver was developed with the DFRobot Light Sensor based on the
BH1750.  It has a sensitivity of .5 to 65535 Lux.  It supports
voltages from 3-5vdc and is connected via I2C.

Signed-off-by: Jon Trulson <jtrulson@ics.com>

examples/c++/CMakeLists.txt

@@ -276,6 +276,7 @@ add_example (bmx055)
 add_example (ms5611)
 add_example (vk2828u7)
 add_example (mma7361)
+add_example (bh1750)
 
 # These are special cases where you specify example binary, source file and module(s)
 include_directories (${PROJECT_SOURCE_DIR}/src)

examples/c++/bh1750.cxx

@@ -0,0 +1,65 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2015 Intel Corporation.
+ *
+ * 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 <unistd.h>
+#include <iostream>
+#include <signal.h>
+#include "bh1750.hpp"
+
+using namespace std;
+
+bool shouldRun = true;
+
+void sig_handler(int signo)
+{
+  if (signo == SIGINT)
+    shouldRun = false;
+}
+
+int main()
+{
+  signal(SIGINT, sig_handler);
+
+//! [Interesting]
+
+  // Instantiate a BH1750 sensor using defaults (I2C bus (0), using
+  // the default I2C address (0x23), and setting the mode to highest
+  // resolution, lowest power mode).
+  upm::BH1750 *sensor = new upm::BH1750();
+
+  // Every second, sample the BH1750 and output the measured lux value
+
+  while (shouldRun)
+    {
+      cout << "Detected Light Level (lux): " << sensor->getLux() << endl;
+      sleep(1);
+    }
+
+//! [Interesting]
+
+  cout << "Exiting" << endl;
+
+  delete sensor;
+  return 0;
+}