mq303a: Initial implementation of the mq303a alcohol sensor

The module implements support for the mq303a alcohol sensor.  It was
tested on the Grove Alcohol 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/mq303a/CMakeLists.txt

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+set (libname "mq303a")
+set (libdescription "upm mq303a module")
+set (module_src ${libname}.cxx)
+set (module_h ${libname}.h)
+upm_module_init()

src/mq303a/jsupm_mq303a.i

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+%module jsupm_mq303a
+%include "../upm.i"
+
+%{
+    #include "mq303a.h"
+%}
+
+%include "mq303a.h"

src/mq303a/mq303a.cxx

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+/*
+ * 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 "mq303a.h"
+
+using namespace upm;
+
+MQ303A::MQ303A(int pin, int heaterPin)
+{
+  m_aio = mraa_aio_init(pin);
+
+  m_gpio = mraa_gpio_init(heaterPin);
+  mraa_gpio_dir(m_gpio, MRAA_GPIO_OUT);
+}
+
+MQ303A::~MQ303A()
+{
+  heaterEnable(false);
+  mraa_aio_close(m_aio);
+  mraa_gpio_close(m_gpio);
+}
+
+int MQ303A::value()
+{
+  return (1023 - mraa_aio_read(m_aio));
+}
+
+void MQ303A::heaterEnable(bool enable)
+{
+  if (enable)
+    mraa_gpio_write(m_gpio, 0);  // 0 turns on the heater
+  else
+    mraa_gpio_write(m_gpio, 1);  // 1 turns off the heater
+}

src/mq303a/mq303a.h

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+/*
+ * 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 <mraa/aio.h>
+
+namespace upm {
+
+  /**
+   * @brief C++ API for the MQ303A Alcohol Sensor
+   *
+   * UPM module for the MQ303A Alcohol Sensor.
+   * This sensor needs to be warmed up before stable results are
+   * obtained.  The higher the value returned from value(),
+   * the higher the amount of alcohol that was detected.
+   *
+   * @ingroup analog gas alcohol
+   * @snippet mq303a.cxx Interesting
+   */
+  class MQ303A {
+  public:
+    /**
+     * MQ303A sensor constructor
+     *
+     * @param pin analog pin to use
+     * @param heaterPin digital pin mapped to analog pin to use
+     */
+    MQ303A(int pin, int heaterPin);
+
+    /**
+     * MQ303A Destructor
+     */
+    ~MQ303A();
+
+    /**
+     * Get the alcohol detected from the sensor.  
+     * The value read from the analog pin is inverted.  
+     * A higher returned value means a higher amount of alcohol was detected.
+     *
+     * @return the alcohol reading
+     */
+    int value();
+
+    /**
+     * Enable the heater.
+     *
+     * @param enable if true, enable the heater else disable
+     */
+    void heaterEnable(bool enable);
+
+  private:
+    mraa_aio_context m_aio;
+    mraa_gpio_context m_gpio;
+  };
+}
+
+

src/mq303a/pyupm_mq303a.i

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+%module pyupm_mq303a
+%include "../upm.i"
+
+%feature("autodoc", "3");
+
+%include "mq303a.h"
+%{
+    #include "mq303a.h"
+%}