mq4: Initial implementation

Signed-off-by: Jon Trulson <jtrulson@ics.com>
Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>

examples/c++/CMakeLists.txt

@@ -41,6 +41,7 @@ add_executable (mlx90614-example mlx90614.cxx)
 add_executable (ecs1030-example ecs1030.cxx)
 add_executable (mq2-example mq2.cxx)
 add_executable (mq3-example mq3.cxx)
+add_executable (mq4-example mq4.cxx)
 add_executable (mq5-example mq5.cxx)
 add_executable (mq7-example mq7.cxx)
 add_executable (mq8-example mq8.cxx)
@@ -298,6 +299,7 @@ target_link_libraries (mlx90614-example mlx90614 ${CMAKE_THREAD_LIBS_INIT})
 target_link_libraries (ecs1030-example ecs1030 ${CMAKE_THREAD_LIBS_INIT})
 target_link_libraries (mq2-example gas ${CMAKE_THREAD_LIBS_INIT})
 target_link_libraries (mq3-example gas ${CMAKE_THREAD_LIBS_INIT})
+target_link_libraries (mq4-example gas ${CMAKE_THREAD_LIBS_INIT})
 target_link_libraries (mq5-example gas ${CMAKE_THREAD_LIBS_INIT})
 target_link_libraries (mq7-example gas ${CMAKE_THREAD_LIBS_INIT})
 target_link_libraries (mq8-example gas ${CMAKE_THREAD_LIBS_INIT})

examples/c++/mq4.cxx

@@ -0,0 +1,81 @@
+/*
+ * 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 "mq4.h"
+#include <signal.h>
+#include <stdlib.h>
+#include <sys/time.h>
+
+bool shouldRun = true;
+
+using namespace std;
+
+void
+sig_handler(int signo)
+{
+  if (signo == SIGINT) 
+    {
+      shouldRun = false;
+    }
+}
+
+//! [Interesting]
+int main(int argc, char **argv)
+{
+  // Attach gas sensor to Analog A0
+  upm::MQ4 *sensor = new upm::MQ4(0);
+  signal(SIGINT, sig_handler);
+  
+  uint16_t buffer [128];
+
+  thresholdContext ctx;
+  ctx.averageReading = 0;
+  ctx.runningAverage = 0;
+  ctx.averagedOver   = 2;
+  
+  // Infinite loop, ends when script is cancelled
+  // Repeatedly, take a sample every 2 microseconds;
+  // find the average of 128 samples; and
+  // print a running graph of asteriskss as averages
+  while (shouldRun) 
+    {
+      int len = sensor->getSampledWindow (2, 128, buffer);
+      if (len) {
+        int thresh = sensor->findThreshold (&ctx, 30, buffer, len);
+        sensor->printGraph(&ctx, 5);
+        if (thresh) {
+          // do something ....
+        }
+      }
+    }
+  
+  cout << "Exiting" << endl;
+  
+  delete sensor;
+  
+  return 0;
+}
+//! [Interesting]