WFS Class Reference

API for the Water Flow Sensor. More...

Detailed Description

• ID: wfs
• Name: Water Flow Sensor
• Other Names: Grove Water Flow Sensor
• Category: liquid
• Manufacturer: seeed
• Link: http://wiki.seeedstudio.com/wiki/G1/2_Water_Flow_sensor
• Connection: gpio
• Kit: eak

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.

    // Instantiate a Water Flow Sensor on digital pin D2.  This must
    // be an interrupt capable pin.
    upm::WFS flow(2);

    // set the flow counter to 0 and start counting
    flow.clearFlowCounter();
    flow.startFlowCounter();

    while (shouldRun) {
        // we grab these (millis and flowCount) just for display
        // purposes in this example
        uint32_t millis = flow.getMillis();
        uint32_t flowCount = flow.flowCounter();

        float fr = flow.flowRate();

        // output milliseconds passed, flow count, and computed flow rate
        cout << "Millis: " << millis << " Flow Count: " << flowCount;
        cout << " Flow Rate: " << fr << " LPM" << endl;

        // best to gather data for at least one second for reasonable
        // results.
        upm_delay(2);
    }

    flow.stopFlowCounter();

Public Member Functions
	WFS (int pin)
	~WFS ()
uint32_t	getMillis ()
void	initClock ()
void	clearFlowCounter ()
void	startFlowCounter ()
void	stopFlowCounter ()
uint32_t	flowCounter ()
float	flowRate ()

Protected Attributes
wfs_context	m_wfs

Constructor & Destructor Documentation

WFS

(

int

pin

)

Water Flow Sensor constructor

Parameters

pin	Digital pin to use

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~WFS

(

)

WFS destructor

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Member Function Documentation

uint32_t getMillis

(

)

Returns the number of milliseconds elapsed since initClock() was last called.

Returns

Elapsed milliseconds

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void initClock

(

)

Resets the clock

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void clearFlowCounter ( )

inline

Resets the flow counter to 0. The flow counter should be stopped via stopFlowCounter() prior to calling this function.

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void startFlowCounter

(

)

Starts the flow counter

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void stopFlowCounter

(

)

Stops the flow counter

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uint32_t flowCounter ( )

inline

Gets the flow counter

Returns

Flow counter

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float flowRate

(

)

Computes the flow rate in liters per minute (LPM). Note, this is for the Grove WFS. If you are using some other WFS, you should compute the flow rate on your own based on the data for your sensor.

Returns

Computed flow rate

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The documentation for this class was generated from the following files:

• src/wfs/wfs.hpp
• src/wfs/wfs.cxx