Package com.diozero.api

Class AnalogInputDevice

java.lang.Object

com.diozero.api.GpioDevice

com.diozero.api.GpioInputDevice<AnalogInputEvent>

com.diozero.api.AnalogInputDevice

All Implemented Interfaces:

DeviceInterface, DeviceEventConsumer<AnalogInputEvent>, AutoCloseable, Runnable, Consumer<AnalogInputEvent>

Direct Known Subclasses:

GP2Y0A21YK, LDR, Potentiometer, TMP36

public class AnalogInputDevice
extends GpioInputDevice<AnalogInputEvent>
implements Runnable

The AnalogInputDevice base class encapsulates logic for interfacing with analog devices. This class provides access to unscaled (-1..1) and scaled (e.g. voltage, temperature, distance) readings. For scaled readings is important that the device factory is configured correctly - all raw analog readings are normalised (i.e. -1..1).

Note: The Raspberry Pi does not natively support analog input devices, see McpAdc for connecting to analog-to-digital converters.

Example: Temperature readings using an MCP3008 and TMP36:

Code taken from TMP36Test:

 
try (McpAdc adc = new McpAdc(type, chipSelect);
	TMP36 tmp36 = new TMP36(adc, pin, vRef, tempOffset)) {
	for (int i=0; i<ITERATIONS; i++) {
		double tmp = tmp36.getTemperature();
		Logger.info("Temperature: {}", String.format("%.2f", Double.valueOf(tmp)));
		SleepUtil.sleepSeconds(.5);
	}
}

 

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	AnalogInputDevice.Builder

Field Summary

Fields inherited from class com.diozero.api.GpioDevice

pinInfo

Constructor Summary

Constructors

Constructor	Description
AnalogInputDevice(int adcNumber)
AnalogInputDevice(int adcNumber, float range)
AnalogInputDevice(AnalogInputDeviceFactoryInterface deviceFactory, int adcNumber)
AnalogInputDevice(AnalogInputDeviceFactoryInterface deviceFactory, int adcNumber, float range)
AnalogInputDevice(AnalogInputDeviceFactoryInterface deviceFactory, PinInfo pinInfo, float range)

Method Summary

Modifier and Type	Method	Description
void	accept(AnalogInputEvent event)
void	addListener(DeviceEventConsumer<AnalogInputEvent> listener, float percentChange)	Register a listener for value changes, will check for changes every 50ms.
void	addListener(DeviceEventConsumer<AnalogInputEvent> listener, float percentChange, int pollInterval)	Register a listener for value changes, will check for changes every 50ms.
void	close()	Close this device
float	convertToScaledValue(float unscaledValue)	Convert the specified unscaled value (-1..1) to a scaled one (-range..range).
protected void	disableDeviceListener()
protected void	enableDeviceListener()
float	getRange()	Get the analog range for this input device as used by getScaledValue() and convertToScaledValue(float)
float	getScaledValue()	Get the scaled value in the range 0..range (if unsigned) or -range..range (if signed)
float	getUnscaledValue()	Get the unscaled normalised value in the range 0..1 (if unsigned) or -1..1 (if signed)
void	run()

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

AnalogInputDevice

public AnalogInputDevice(int adcNumber)
                  throws RuntimeIOException

Parameters:

adcNumber - GPIO to which the device is connected.

Throws:

RuntimeIOException - If an I/O error occurred.

AnalogInputDevice

public AnalogInputDevice(int adcNumber,
                         float range)
                  throws RuntimeIOException

Parameters:

adcNumber - GPIO to which the device is connected.

range - To be used for taking scaled readings for this device.

Throws:

RuntimeIOException - If an I/O error occurred.

AnalogInputDevice

public AnalogInputDevice(AnalogInputDeviceFactoryInterface deviceFactory,
                         int adcNumber)
                  throws RuntimeIOException

Parameters:

deviceFactory - The device factory to use to provision this device.

adcNumber - GPIO to which the device is connected.

Throws:

RuntimeIOException - If an I/O error occurred.

AnalogInputDevice

public AnalogInputDevice(AnalogInputDeviceFactoryInterface deviceFactory,
                         int adcNumber,
                         float range)
                  throws RuntimeIOException

Parameters:

deviceFactory - The device factory to use to provision this device.

adcNumber - GPIO to which the device is connected.

range - To be used for taking scaled readings for this device.

Throws:

RuntimeIOException - If an I/O error occurred.

AnalogInputDevice

public AnalogInputDevice(AnalogInputDeviceFactoryInterface deviceFactory,
                         PinInfo pinInfo,
                         float range)
                  throws RuntimeIOException

Parameters:

deviceFactory - The device factory to use to provision this device.

pinInfo - GPIO to which the device is connected.

range - To be used for taking scaled readings for this device.

Throws:

RuntimeIOException - If an I/O error occurred.

Method Detail

close

public void close()
           throws RuntimeIOException

Description copied from interface: DeviceInterface

Close this device

Specified by:

close in interface AutoCloseable

Specified by:

close in interface DeviceInterface

Throws:

RuntimeIOException

enableDeviceListener

protected void enableDeviceListener()

Specified by:

enableDeviceListener in class GpioInputDevice<AnalogInputEvent>

disableDeviceListener

protected void disableDeviceListener()

Specified by:

disableDeviceListener in class GpioInputDevice<AnalogInputEvent>

run

public void run()

Specified by:

run in interface Runnable

accept

public void accept(AnalogInputEvent event)

Specified by:

accept in interface Consumer<AnalogInputEvent>

Overrides:

accept in class GpioInputDevice<AnalogInputEvent>

getRange

public float getRange()

Get the analog range for this input device as used by getScaledValue() and convertToScaledValue(float)

Returns:

the analog range for this input device

getUnscaledValue

public float getUnscaledValue()
                       throws RuntimeIOException

Get the unscaled normalised value in the range 0..1 (if unsigned) or -1..1 (if signed)

Returns:

the unscaled value

Throws:

RuntimeIOException - if there was an I/O error

getScaledValue

public float getScaledValue()
                     throws RuntimeIOException

Get the scaled value in the range 0..range (if unsigned) or -range..range (if signed)

Returns:

the scaled value (-range..range)

Throws:

RuntimeIOException - if there was an I/O error

convertToScaledValue

public float convertToScaledValue(float unscaledValue)

Convert the specified unscaled value (-1..1) to a scaled one (-range..range).

Parameters:

unscaledValue - the unscaled value in the range -1..1

Returns:

the scaled value in -range..range

See Also:

getRange()

addListener

public void addListener(DeviceEventConsumer<AnalogInputEvent> listener,
                        float percentChange)

Register a listener for value changes, will check for changes every 50ms.

Parameters:

listener - The listener callback.

percentChange - Degree of change required to trigger an event.

addListener

public void addListener(DeviceEventConsumer<AnalogInputEvent> listener,
                        float percentChange,
                        int pollInterval)

Register a listener for value changes, will check for changes every 50ms.

Parameters:

listener - The listener callback.

percentChange - Degree of change required to trigger an event.

pollInterval - Time in milliseconds at which reading should be taken.