Package com.diozero.api

Class SmoothedInputDevice

java.lang.Object

com.diozero.api.GpioDevice

com.diozero.api.GpioInputDevice<DigitalInputEvent>

com.diozero.api.AbstractDigitalInputDevice

com.diozero.api.DigitalInputDevice

com.diozero.api.SmoothedInputDevice

All Implemented Interfaces:

DeviceInterface, DigitalInputDeviceInterface, DeviceEventConsumer<DigitalInputEvent>, AutoCloseable, Runnable, Consumer<DigitalInputEvent>

Direct Known Subclasses:

MotionSensor

public class SmoothedInputDevice
extends DigitalInputDevice
implements Runnable

Represents a generic input device which takes its value from the number of active events over a specific time period.

This class extends DigitalInputDevice with a queue which is added to whenever the input device is active. The number of the active events in the queue is compared to a threshold which is used to determine the state of the 'active' property.

Any active events over the specified eventAge are removed by a background thread.

This class is intended for use with devices which exhibit "twitchy" behaviour (such as certain motion sensors). It can enable basic debounce functionality by setting threshold to 1, eventAge = -1 and eventDetectPeriod = debounceTime (ms).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	SmoothedInputDevice.Builder	Smoothed input device builder.

Field Summary

Fields inherited from class com.diozero.api.AbstractDigitalInputDevice

activeHigh

Fields inherited from class com.diozero.api.GpioDevice

pinInfo

Constructor Summary

Constructors

Constructor	Description
SmoothedInputDevice(int gpio, GpioPullUpDown pud, int threshold, int eventAge, int eventDetectPeriod)
SmoothedInputDevice(GpioDeviceFactoryInterface deviceFactory, int gpio, GpioPullUpDown pud, int threshold, int eventAge, int eventDetectPeriod)
SmoothedInputDevice(GpioDeviceFactoryInterface deviceFactory, PinInfo pinInfo, GpioPullUpDown pud, boolean activeHigh, int threshold, int eventAge, int eventDetectPeriod)

Method Summary

Modifier and Type	Method	Description
void	accept(DigitalInputEvent event)
int	getEventAge()	The time in milliseconds to keep items in the queue.
int	getEventDetectPeriod()	How frequently (in milliseconds) to check the state of the queue.
int	getThreshold()	If the number of on events younger than eventAge exceeds this amount, then 'isActive' will return 'True'.
void	run()
void	setEventAge(int eventAge)	Set the event age (milliseconds).
void	setThreshold(int threshold)	Set the threshold value in terms of number of on events within the specified time period that will trigger an on event to any listeners.

Methods inherited from class com.diozero.api.DigitalInputDevice

close, getPullUpDown, getTrigger, getValue, isActive, removeListener, setListener

Methods inherited from class com.diozero.api.AbstractDigitalInputDevice

disableDeviceListener, enableDeviceListener, isActiveHigh, waitForActive, waitForActive, waitForInactive, waitForInactive, waitForValue, whenActivated, whenDeactivated

Methods inherited from class com.diozero.api.GpioInputDevice

addListener, hasListeners, removeAllListeners, removeListener

Methods inherited from class com.diozero.api.GpioDevice

getGpio

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.function.Consumer

andThen

Constructor Detail

SmoothedInputDevice

public SmoothedInputDevice(int gpio,
                           GpioPullUpDown pud,
                           int threshold,
                           int eventAge,
                           int eventDetectPeriod)
                    throws RuntimeIOException

Parameters:

gpio - GPIO to which the device is connected.

pud - Pull up/down configuration, values: NONE, PULL_UP, PULL_DOWN.

threshold - The value above which the device will be considered "on".

eventAge - The time in milliseconds to keep active events in the queue.

eventDetectPeriod - How frequently to check for events.

Throws:

RuntimeIOException - if an I/O error occurs

SmoothedInputDevice

public SmoothedInputDevice(GpioDeviceFactoryInterface deviceFactory,
                           int gpio,
                           GpioPullUpDown pud,
                           int threshold,
                           int eventAge,
                           int eventDetectPeriod)
                    throws RuntimeIOException

Parameters:

deviceFactory - Device factory to use to provision this device.

gpio - GPIO to which the device is connected.

pud - Pull up/down configuration, values: NONE, PULL_UP, PULL_DOWN.

threshold - The value above which the device will be considered "on".

eventAge - The time in milliseconds to keep active events in the queue.

eventDetectPeriod - How frequently to check for events.

Throws:

RuntimeIOException - if an I/O error occurs

SmoothedInputDevice

public SmoothedInputDevice(GpioDeviceFactoryInterface deviceFactory,
                           PinInfo pinInfo,
                           GpioPullUpDown pud,
                           boolean activeHigh,
                           int threshold,
                           int eventAge,
                           int eventDetectPeriod)
                    throws RuntimeIOException

Parameters:

deviceFactory - Device factory to use to provision this device

pinInfo - PinInfo instance to which the device is connected

pud - Pull up/down configuration, values: NONE, PULL_UP, PULL_DOWN

activeHigh - Set to true if digital 1 is to be treated as active

threshold - The value above which the device will be considered "on"

eventAge - The time in milliseconds to keep active events in the queue

eventDetectPeriod - How frequently to check for events

Throws:

RuntimeIOException - if an I/O error occurs

Method Detail

accept

public void accept(DigitalInputEvent event)

Specified by:

accept in interface Consumer<DigitalInputEvent>

Overrides:

accept in class AbstractDigitalInputDevice

run

public void run()

Specified by:

run in interface Runnable

getThreshold

public int getThreshold()

If the number of on events younger than eventAge exceeds this amount, then 'isActive' will return 'True'.

Returns:

event threshold

setThreshold

public void setThreshold(int threshold)

Set the threshold value in terms of number of on events within the specified time period that will trigger an on event to any listeners.

Parameters:

threshold - New threshold value.

getEventAge

public int getEventAge()

The time in milliseconds to keep items in the queue.

Returns:

The event age (milliseconds).

setEventAge

public void setEventAge(int eventAge)

Set the event age (milliseconds).

Parameters:

eventAge - New event age value (milliseconds).

getEventDetectPeriod

public int getEventDetectPeriod()

How frequently (in milliseconds) to check the state of the queue.

Returns:

The event detection period (milliseconds)