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.h

@@ -0,0 +1,99 @@
+/*
+ * 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.
+ */
+#pragma once
+
+#include <string>
+#include <iostream>
+#include <stdint.h>
+#include <sys/time.h>
+#include <mraa/aio.h>
+
+// default ADC resolution. 
+#define TA12200_ADC_RES 1024
+
+namespace upm {
+
+  /**
+   * @brief C++ API for the TA12-200 current transformer
+   *
+   * UPM module for the TA12-200 current transformer, which is found,
+   * for instance, in the Grove Electricity Sensor. 
+   * This module can measure AC current moving through a wire at up 
+   * to 5A.
+   *
+   * @ingroup analog
+   * @snippet ta12200.cxx Interesting
+   */
+  class TA12200 {
+  public:
+    /**
+     * TA12200 sensor constructor
+     *
+     * @param pin analog pin to use
+     */
+    TA12200(int pin);
+
+    /**
+     * TA12200 Destructor
+     */
+    ~TA12200();
+
+    /**
+     * Return the number of milliseconds elapsed since initClock()
+     * was last called.
+     *
+     * @return elapsed milliseconds
+     */
+    uint32_t getMillis();
+
+    /**
+     * Reset the Clock
+     *
+     */
+    void initClock();
+
+    /**
+     * Get the conversion value from the sensor
+     *
+     * @return the highest value obtained over 1 second of measuring
+     */
+    unsigned int highestValue();
+
+    /**
+     * Compute the measured voltage
+     *
+     * @param val value measured by highestValue()
+     * @param res ADC resolution
+     *
+     * @return the measured current in milliamps
+     */
+    float milliAmps(unsigned int val, int res=TA12200_ADC_RES);
+
+  private:
+    struct timeval m_startTime;
+    mraa_aio_context m_aio;
+  };
+}
+
+