ta12200: Initial implementation; Grove Electricity uses this sensor

[renamed from] groveelectricity: Initial implementation

This module adds support for the Grove Electricity sensor.

Signed-off-by: Jon Trulson <jtrulson@ics.com>
Signed-off-by: Zion Orent <zorent@ics.com>
Signed-off-by: Sarah Knepper <sarah.knepper@intel.com>

src/ta12200/ta12200.cxx

@@ -0,0 +1,112 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2014 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 <iostream>
+
+#include "ta12200.h"
+
+using namespace upm;
+using namespace std;
+
+TA12200::TA12200(int pin)
+{
+  initClock();
+
+  if ( !(m_aio = mraa_aio_init(pin)) )
+    {
+      cerr << __FUNCTION__ << ": mraa_aio_init() failed" << endl;
+      return;
+    }
+}
+
+TA12200::~TA12200()
+{
+  mraa_aio_close(m_aio);
+}
+
+void TA12200::initClock()
+{
+  gettimeofday(&m_startTime, NULL);
+}
+
+uint32_t TA12200::getMillis()
+{
+  struct timeval elapsed, now;
+  uint32_t elapse;
+
+  // get current time
+  gettimeofday(&now, NULL);
+
+  // compute the delta since m_startTime
+  if( (elapsed.tv_usec = now.tv_usec - m_startTime.tv_usec) < 0 ) 
+    {
+      elapsed.tv_usec += 1000000;
+      elapsed.tv_sec = now.tv_sec - m_startTime.tv_sec - 1;
+    } 
+  else 
+    {
+      elapsed.tv_sec = now.tv_sec - m_startTime.tv_sec;
+    }
+
+  elapse = (uint32_t)((elapsed.tv_sec * 1000) + (elapsed.tv_usec / 1000));
+
+  // never return 0
+  if (elapse == 0)
+    elapse = 1;
+
+  return elapse;
+}
+
+
+unsigned int TA12200::highestValue()
+{
+  unsigned int hiVal = 0;
+  unsigned int val;
+  uint32_t start = getMillis();
+
+  // 1 second
+  while (getMillis() < (start + 1000))
+    {
+      val = mraa_aio_read(m_aio);
+      if (val > hiVal)
+        hiVal = val;
+    }
+        
+  return hiVal;
+}
+
+float TA12200::milliAmps(unsigned int val, int res)
+{
+  float ampCurrent;
+  float effectiveVal;
+
+  // From grove wiki page:
+  // minimum_current=1/1024*5/800*2000000/1.414=8.6(mA) 
+  // Only for sinusoidal alternating current
+  //ampCurrent = float(val) / float(res) * 5.0 / 800.0 * 2000000.0;
+  ampCurrent = float(val) / float(res) * 12500.0;
+  effectiveVal = ampCurrent/1.414;
+  return (effectiveVal);
+}
+