upm/src/grovewfs/grovewfs.h

/*
 * 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.
 */
#pragma once

#include <string>
#include <stdint.h>
#include <sys/time.h>
#include <mraa/gpio.h>

namespace upm {

  /**
   * @brief Grove Water Flow Sensor library
   * @defgroup grovewfs libupm-grovewfs
   * @ingroup seeed gpio liquid eak
   */

  /**
   * @library grovewfs
   * @sensor grovewfs
   * @comname Grove Water Flow Sensor
   * @type liquid
   * @man seeed
   * @web http://www.seeedstudio.com/wiki/index.php?title=G1/2_Water_Flow_sensor
   * @con gpio
   * @kit eak

   * @brief API for the Grove Water Flow Sensor
   *
   * This sensor is used to measure water flow in liters per
   * minute (LPM). It incorporates a Hall Effect sensor. The UPM module
   * defines an interrupt routine to be triggered on each low pulse,
   * keeping count. This device requires a 10K pull-up resistor for
   * the signal line (yellow wire). There is a schematic diagram on
   * the SeeedStudio site (3/2015):
   * http://www.seeedstudio.com/wiki/index.php?title=G1/2_Water_Flow_sensor
   *
   * However, be careful when wiring this up - the schematic appears to
   * have a bug in it: the lower left connection of the signal line
   * (yellow) to Vcc (red) should not be there. The sensor can work
   * with this connection, but probably not for very long.
   *
   * @image html grovewfs.jpg
   * @snippet grovewfs.cxx Interesting
   */
  class GroveWFS {
  public:
    /**
     * Grove Water Flow sensor constructor
     *
     * @param pin Digital pin to use
     */
    GroveWFS(int pin);
    /**
     * GroveWFS destructor
     */
    ~GroveWFS();
    /**
     * Returns the number of milliseconds elapsed since initClock()
     * was last called.
     *
     * @return Elapsed milliseconds
     */
    uint32_t getMillis();

    /**
     * Resets the clock
     *
     */
    void initClock();

    /**
     * Resets the flow counter to 0. The flow counter should be
     * stopped via stopFlowCounter() prior to calling this function.
     *
     */
    void clearFlowCounter() { m_flowCounter = 0; };

    /**
     * Starts the flow counter
     *
     */
    void startFlowCounter();

    /**
     * Stops the flow counter
     *
     */
    void stopFlowCounter();

    /**
     * Gets the flow counter
     *
     * @return Flow counter
     */
    uint32_t flowCounter() { return m_flowCounter; };

    /**
     * Computes the flow rate in liters per minute (LPM)
     *
     * @return Computed flow rate
     */
    float flowRate();

  private:
    /**
     * Flow interrupt service routine (ISR)
     *
     */
    static void flowISR(void *ctx);

    volatile uint32_t m_flowCounter;
    struct timeval m_startTime;
    mraa_gpio_context m_gpio;
    bool m_isrInstalled;
  };
}