com.diozero.api

Class AnalogInputDevice

java.lang.Object

com.diozero.api.GpioDevice

com.diozero.api.GpioInputDevice<AnalogInputEvent>

com.diozero.api.AnalogInputDevice

All Implemented Interfaces:

InputEventListener<AnalogInputEvent>, Closeable, AutoCloseable, Runnable

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);
	}
}

 

Field Summary

Fields inherited from class com.diozero.api.GpioDevice

gpio

Constructor Summary

Constructors

Constructor and Description
AnalogInputDevice(AnalogInputDeviceFactoryInterface deviceFactory, int gpio)
AnalogInputDevice(AnalogInputDeviceFactoryInterface deviceFactory, int gpio, float range)
AnalogInputDevice(int gpio)
AnalogInputDevice(int gpio, float range)

Method Summary

Modifier and Type	Method and Description
void	addListener(InputEventListener<AnalogInputEvent> listener, float percentChange) Register a listener for value changes, will check for changes every 50ms.
void	addListener(InputEventListener<AnalogInputEvent> listener, float percentChange, int pollInterval) Register a listener for value changes, will check for changes every 50ms.
void	close()
protected void	disableDeviceListener()
protected void	enableDeviceListener()
float	getRange()
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()
void	valueChanged(AnalogInputEvent event)

Methods inherited from class com.diozero.api.GpioInputDevice

addListener, 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

Constructor Detail

AnalogInputDevice

public AnalogInputDevice(int gpio)
                  throws RuntimeIOException

Parameters:

gpio - GPIO to which the device is connected.

Throws:

RuntimeIOException - If an I/O error occurred.

AnalogInputDevice

public AnalogInputDevice(int gpio,
                         float range)
                  throws RuntimeIOException

Parameters:

gpio - 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 gpio)
                  throws RuntimeIOException

Parameters:

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

gpio - GPIO to which the device is connected.

Throws:

RuntimeIOException - If an I/O error occurred.

AnalogInputDevice

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

Parameters:

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

gpio - 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

getRange

public float getRange()

close

public void close()
           throws RuntimeIOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

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

valueChanged

public void valueChanged(AnalogInputEvent event)

Specified by:

valueChanged in interface InputEventListener<AnalogInputEvent>

Overrides:

valueChanged in class GpioInputDevice<AnalogInputEvent>

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

Throws:

RuntimeIOException - if there was an I/O error

addListener

public void addListener(InputEventListener<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(InputEventListener<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.