Java - Accelerometer Bricklet

This is the description of the Java API bindings for the Accelerometer Bricklet. General information and technical specifications for the Accelerometer Bricklet are summarized in its hardware description.

An installation guide for the Java API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Simple

Download (ExampleSimple.java)

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import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletAccelerometer;
import com.tinkerforge.BrickletAccelerometer.Acceleration;

public class ExampleSimple {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;

    // Change XYZ to the UID of your Accelerometer Bricklet
    private static final String UID = "XYZ";

    // Note: To make the example code cleaner we do not handle exceptions. Exceptions
    //       you might normally want to catch are described in the documentation
    public static void main(String args[]) throws Exception {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletAccelerometer a = new BrickletAccelerometer(UID, ipcon); // Create device object

        ipcon.connect(HOST, PORT); // Connect to brickd
        // Don't use device before ipcon is connected

        // Get current acceleration
        Acceleration acceleration = a.getAcceleration(); // Can throw com.tinkerforge.TimeoutException

        System.out.println("Acceleration [X]: " + acceleration.x/1000.0 + " g");
        System.out.println("Acceleration [Y]: " + acceleration.y/1000.0 + " g");
        System.out.println("Acceleration [Z]: " + acceleration.z/1000.0 + " g");

        System.out.println("Press key to exit"); System.in.read();
        ipcon.disconnect();
    }
}

Callback

Download (ExampleCallback.java)

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import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletAccelerometer;

public class ExampleCallback {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;

    // Change XYZ to the UID of your Accelerometer Bricklet
    private static final String UID = "XYZ";

    // Note: To make the example code cleaner we do not handle exceptions. Exceptions
    //       you might normally want to catch are described in the documentation
    public static void main(String args[]) throws Exception {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletAccelerometer a = new BrickletAccelerometer(UID, ipcon); // Create device object

        ipcon.connect(HOST, PORT); // Connect to brickd
        // Don't use device before ipcon is connected

        // Add acceleration listener
        a.addAccelerationListener(new BrickletAccelerometer.AccelerationListener() {
            public void acceleration(short x, short y, short z) {
                System.out.println("Acceleration [X]: " + x/1000.0 + " g");
                System.out.println("Acceleration [Y]: " + y/1000.0 + " g");
                System.out.println("Acceleration [Z]: " + z/1000.0 + " g");
                System.out.println("");
            }
        });

        // Set period for acceleration callback to 1s (1000ms)
        // Note: The acceleration callback is only called every second
        //       if the acceleration has changed since the last call!
        a.setAccelerationCallbackPeriod(1000);

        System.out.println("Press key to exit"); System.in.read();
        ipcon.disconnect();
    }
}

Threshold

Download (ExampleThreshold.java)

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import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletAccelerometer;

public class ExampleThreshold {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;

    // Change XYZ to the UID of your Accelerometer Bricklet
    private static final String UID = "XYZ";

    // Note: To make the example code cleaner we do not handle exceptions. Exceptions
    //       you might normally want to catch are described in the documentation
    public static void main(String args[]) throws Exception {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletAccelerometer a = new BrickletAccelerometer(UID, ipcon); // Create device object

        ipcon.connect(HOST, PORT); // Connect to brickd
        // Don't use device before ipcon is connected

        // Get threshold callbacks with a debounce time of 10 seconds (10000ms)
        a.setDebouncePeriod(10000);

        // Add acceleration reached listener
        a.addAccelerationReachedListener(new BrickletAccelerometer.AccelerationReachedListener() {
            public void accelerationReached(short x, short y, short z) {
                System.out.println("Acceleration [X]: " + x/1000.0 + " g");
                System.out.println("Acceleration [Y]: " + y/1000.0 + " g");
                System.out.println("Acceleration [Z]: " + z/1000.0 + " g");
                System.out.println("");
            }
        });

        // Configure threshold for acceleration "greater than 2 g, 2 g, 2 g"
        a.setAccelerationCallbackThreshold('>', (short)(2*1000), (short)0,
                                           (short)(2*1000), (short)0, (short)(2*1000),
                                           (short)0);

        System.out.println("Press key to exit"); System.in.read();
        ipcon.disconnect();
    }
}

API

Generally, every method of the Java bindings that returns a value can throw a TimeoutException. This exception gets thrown if the device did not respond. If a cable based connection is used, it is unlikely that this exception gets thrown (assuming nobody unplugs the device). However, if a wireless connection is used, timeouts will occur if the distance to the device gets too big.

Beside the TimeoutException there is also a NotConnectedException that is thrown if a method needs to communicate with the device while the IP Connection is not connected.

Since Java does not support multiple return values and return by reference is not possible for primitive types, we use small classes that only consist of member variables. The member variables of the returned objects are described in the corresponding method descriptions.

The package for all Brick/Bricklet bindings and the IP Connection is com.tinkerforge.*

All methods listed below are thread-safe.

Basic Functions

class BrickletAccelerometer(String uid, IPConnection ipcon)
Parameters:
  • uid – Type: String
  • ipcon – Type: IPConnection
Returns:
  • accelerometer – Type: BrickletAccelerometer

Creates an object with the unique device ID uid:

BrickletAccelerometer accelerometer = new BrickletAccelerometer("YOUR_DEVICE_UID", ipcon);

This object can then be used after the IP Connection is connected (see examples above).

BrickletAccelerometer.Acceleration BrickletAccelerometer.getAcceleration()
Return Object:
  • x – Type: short, Unit: 1/1000 gₙ, Range: ?
  • y – Type: short, Unit: 1/1000 gₙ, Range: ?
  • z – Type: short, Unit: 1/1000 gₙ, Range: ?

Returns the acceleration in x, y and z direction. The values are given in gₙ/1000 (1gₙ = 9.80665m/s²). The range is configured with setConfiguration().

If you want to get the acceleration periodically, it is recommended to use the AccelerationListener listener and set the period with setAccelerationCallbackPeriod().

short BrickletAccelerometer.getTemperature()
Returns:
  • temperature – Type: short, Unit: 1 °C, Range: [-103 to 152]

Returns the temperature of the accelerometer.

void BrickletAccelerometer.ledOn()

Enables the LED on the Bricklet.

void BrickletAccelerometer.ledOff()

Disables the LED on the Bricklet.

boolean BrickletAccelerometer.isLEDOn()
Returns:
  • on – Type: boolean, Default: false

Returns true if the LED is enabled, false otherwise.

Advanced Functions

void BrickletAccelerometer.setConfiguration(short dataRate, short fullScale, short filterBandwidth)
Parameters:
  • dataRate – Type: short, Range: See constants, Default: 6
  • fullScale – Type: short, Range: See constants, Default: 1
  • filterBandwidth – Type: short, Range: See constants, Default: 2

Configures the data rate, full scale range and filter bandwidth. Possible values are:

  • Data rate of 0Hz to 1600Hz.
  • Full scale range of ±2gₙ up to ±16gₙ.
  • Filter bandwidth between 50Hz and 800Hz.

Decreasing data rate or full scale range will also decrease the noise on the data.

The following constants are available for this function:

For dataRate:

  • BrickletAccelerometer.DATA_RATE_OFF = 0
  • BrickletAccelerometer.DATA_RATE_3HZ = 1
  • BrickletAccelerometer.DATA_RATE_6HZ = 2
  • BrickletAccelerometer.DATA_RATE_12HZ = 3
  • BrickletAccelerometer.DATA_RATE_25HZ = 4
  • BrickletAccelerometer.DATA_RATE_50HZ = 5
  • BrickletAccelerometer.DATA_RATE_100HZ = 6
  • BrickletAccelerometer.DATA_RATE_400HZ = 7
  • BrickletAccelerometer.DATA_RATE_800HZ = 8
  • BrickletAccelerometer.DATA_RATE_1600HZ = 9

For fullScale:

  • BrickletAccelerometer.FULL_SCALE_2G = 0
  • BrickletAccelerometer.FULL_SCALE_4G = 1
  • BrickletAccelerometer.FULL_SCALE_6G = 2
  • BrickletAccelerometer.FULL_SCALE_8G = 3
  • BrickletAccelerometer.FULL_SCALE_16G = 4

For filterBandwidth:

  • BrickletAccelerometer.FILTER_BANDWIDTH_800HZ = 0
  • BrickletAccelerometer.FILTER_BANDWIDTH_400HZ = 1
  • BrickletAccelerometer.FILTER_BANDWIDTH_200HZ = 2
  • BrickletAccelerometer.FILTER_BANDWIDTH_50HZ = 3
BrickletAccelerometer.Configuration BrickletAccelerometer.getConfiguration()
Return Object:
  • dataRate – Type: short, Range: See constants, Default: 6
  • fullScale – Type: short, Range: See constants, Default: 1
  • filterBandwidth – Type: short, Range: See constants, Default: 2

Returns the configuration as set by setConfiguration().

The following constants are available for this function:

For dataRate:

  • BrickletAccelerometer.DATA_RATE_OFF = 0
  • BrickletAccelerometer.DATA_RATE_3HZ = 1
  • BrickletAccelerometer.DATA_RATE_6HZ = 2
  • BrickletAccelerometer.DATA_RATE_12HZ = 3
  • BrickletAccelerometer.DATA_RATE_25HZ = 4
  • BrickletAccelerometer.DATA_RATE_50HZ = 5
  • BrickletAccelerometer.DATA_RATE_100HZ = 6
  • BrickletAccelerometer.DATA_RATE_400HZ = 7
  • BrickletAccelerometer.DATA_RATE_800HZ = 8
  • BrickletAccelerometer.DATA_RATE_1600HZ = 9

For fullScale:

  • BrickletAccelerometer.FULL_SCALE_2G = 0
  • BrickletAccelerometer.FULL_SCALE_4G = 1
  • BrickletAccelerometer.FULL_SCALE_6G = 2
  • BrickletAccelerometer.FULL_SCALE_8G = 3
  • BrickletAccelerometer.FULL_SCALE_16G = 4

For filterBandwidth:

  • BrickletAccelerometer.FILTER_BANDWIDTH_800HZ = 0
  • BrickletAccelerometer.FILTER_BANDWIDTH_400HZ = 1
  • BrickletAccelerometer.FILTER_BANDWIDTH_200HZ = 2
  • BrickletAccelerometer.FILTER_BANDWIDTH_50HZ = 3
BrickletAccelerometer.Identity BrickletAccelerometer.getIdentity()
Return Object:
  • uid – Type: String, Length: up to 8
  • connectedUid – Type: String, Length: up to 8
  • position – Type: char, Range: ['a' to 'h', 'i', 'z']
  • hardwareVersion – Type: short[], Length: 3
    • 0: major – Type: short, Range: [0 to 255]
    • 1: minor – Type: short, Range: [0 to 255]
    • 2: revision – Type: short, Range: [0 to 255]
  • firmwareVersion – Type: short[], Length: 3
    • 0: major – Type: short, Range: [0 to 255]
    • 1: minor – Type: short, Range: [0 to 255]
    • 2: revision – Type: short, Range: [0 to 255]
  • deviceIdentifier – Type: int, Range: [0 to 216 - 1]

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). The Raspberry Pi HAT (Zero) Brick is always at position 'i' and the Bricklet connected to an Isolator Bricklet is always as position 'z'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Listener Configuration Functions

void BrickletAccelerometer.setAccelerationCallbackPeriod(long period)
Parameters:
  • period – Type: long, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Sets the period with which the AccelerationListener listener is triggered periodically. A value of 0 turns the listener off.

The AccelerationListener listener is only triggered if the acceleration has changed since the last triggering.

long BrickletAccelerometer.getAccelerationCallbackPeriod()
Returns:
  • period – Type: long, Unit: 1 ms, Range: [0 to 232 - 1], Default: 0

Returns the period as set by setAccelerationCallbackPeriod().

void BrickletAccelerometer.setAccelerationCallbackThreshold(char option, short minX, short maxX, short minY, short maxY, short minZ, short maxZ)
Parameters:
  • option – Type: char, Range: See constants, Default: 'x'
  • minX – Type: short, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • maxX – Type: short, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • minY – Type: short, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • maxY – Type: short, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • minZ – Type: short, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • maxZ – Type: short, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0

Sets the thresholds for the AccelerationReachedListener listener.

The following options are possible:

Option Description
'x' Listener is turned off
'o' Listener is triggered when the acceleration is outside the min and max values
'i' Listener is triggered when the acceleration is inside the min and max values
'<' Listener is triggered when the acceleration is smaller than the min value (max is ignored)
'>' Listener is triggered when the acceleration is greater than the min value (max is ignored)

The following constants are available for this function:

For option:

  • BrickletAccelerometer.THRESHOLD_OPTION_OFF = 'x'
  • BrickletAccelerometer.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletAccelerometer.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletAccelerometer.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletAccelerometer.THRESHOLD_OPTION_GREATER = '>'
BrickletAccelerometer.AccelerationCallbackThreshold BrickletAccelerometer.getAccelerationCallbackThreshold()
Return Object:
  • option – Type: char, Range: See constants, Default: 'x'
  • minX – Type: short, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • maxX – Type: short, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • minY – Type: short, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • maxY – Type: short, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • minZ – Type: short, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0
  • maxZ – Type: short, Unit: 1/1000 gₙ, Range: [-215 to 215 - 1], Default: 0

Returns the threshold as set by setAccelerationCallbackThreshold().

The following constants are available for this function:

For option:

  • BrickletAccelerometer.THRESHOLD_OPTION_OFF = 'x'
  • BrickletAccelerometer.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletAccelerometer.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletAccelerometer.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletAccelerometer.THRESHOLD_OPTION_GREATER = '>'
void BrickletAccelerometer.setDebouncePeriod(long debounce)
Parameters:
  • debounce – Type: long, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Sets the period with which the threshold listener

is triggered, if the threshold

keeps being reached.

long BrickletAccelerometer.getDebouncePeriod()
Returns:
  • debounce – Type: long, Unit: 1 ms, Range: [0 to 232 - 1], Default: 100

Returns the debounce period as set by setDebouncePeriod().

Listeners

Listeners can be registered to receive time critical or recurring data from the device. The registration is done with add*Listener() functions of the device object.

The parameter is a listener class object, for example:

device.addExampleListener(new BrickletAccelerometer.ExampleListener() {
    public void property(int value) {
        System.out.println("Value: " + value);
    }
});

The available listener classes with inherent methods to be overwritten are described below. It is possible to add several listeners and to remove them with the corresponding remove*Listener() function.

Note

Using listeners for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

class BrickletAccelerometer.AccelerationListener()

This listener can be added with the addAccelerationListener() function. An added listener can be removed with the removeAccelerationListener() function.

void acceleration(short x, short y, short z)
Parameters:
  • x – Type: short, Unit: 1/1000 gₙ, Range: ?
  • y – Type: short, Unit: 1/1000 gₙ, Range: ?
  • z – Type: short, Unit: 1/1000 gₙ, Range: ?

This listener is triggered periodically with the period that is set by setAccelerationCallbackPeriod(). The parameters are the X, Y and Z acceleration. The range is configured with setConfiguration().

The AccelerationListener listener is only triggered if the acceleration has changed since the last triggering.

class BrickletAccelerometer.AccelerationReachedListener()

This listener can be added with the addAccelerationReachedListener() function. An added listener can be removed with the removeAccelerationReachedListener() function.

void accelerationReached(short x, short y, short z)
Parameters:
  • x – Type: short, Unit: 1/1000 gₙ, Range: ?
  • y – Type: short, Unit: 1/1000 gₙ, Range: ?
  • z – Type: short, Unit: 1/1000 gₙ, Range: ?

This listener is triggered when the threshold as set by setAccelerationCallbackThreshold() is reached. The parameters are the X, Y and Z acceleration. The range is configured with setConfiguration().

If the threshold keeps being reached, the listener is triggered periodically with the period as set by setDebouncePeriod().

Virtual Functions

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

short[] BrickletAccelerometer.getAPIVersion()
Return Object:
  • apiVersion – Type: short[], Length: 3
    • 0: major – Type: short, Range: [0 to 255]
    • 1: minor – Type: short, Range: [0 to 255]
    • 2: revision – Type: short, Range: [0 to 255]

Returns the version of the API definition implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

boolean BrickletAccelerometer.getResponseExpected(short functionId)
Parameters:
  • functionId – Type: short, Range: See constants
Returns:
  • responseExpected – Type: boolean

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For listener configuration functions it is enabled by default too, but can be disabled by setResponseExpected(). For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • BrickletAccelerometer.FUNCTION_SET_ACCELERATION_CALLBACK_PERIOD = 2
  • BrickletAccelerometer.FUNCTION_SET_ACCELERATION_CALLBACK_THRESHOLD = 4
  • BrickletAccelerometer.FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • BrickletAccelerometer.FUNCTION_SET_CONFIGURATION = 9
  • BrickletAccelerometer.FUNCTION_LED_ON = 11
  • BrickletAccelerometer.FUNCTION_LED_OFF = 12
void BrickletAccelerometer.setResponseExpected(short functionId, boolean responseExpected)
Parameters:
  • functionId – Type: short, Range: See constants
  • responseExpected – Type: boolean

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and listener configuration functions (default value: true). For getter functions it is always enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • BrickletAccelerometer.FUNCTION_SET_ACCELERATION_CALLBACK_PERIOD = 2
  • BrickletAccelerometer.FUNCTION_SET_ACCELERATION_CALLBACK_THRESHOLD = 4
  • BrickletAccelerometer.FUNCTION_SET_DEBOUNCE_PERIOD = 6
  • BrickletAccelerometer.FUNCTION_SET_CONFIGURATION = 9
  • BrickletAccelerometer.FUNCTION_LED_ON = 11
  • BrickletAccelerometer.FUNCTION_LED_OFF = 12
void BrickletAccelerometer.setResponseExpectedAll(boolean responseExpected)
Parameters:
  • responseExpected – Type: boolean

Changes the response expected flag for all setter and listener configuration functions of this device at once.

Constants

int BrickletAccelerometer.DEVICE_IDENTIFIER

This constant is used to identify a Accelerometer Bricklet.

The getIdentity() function and the IPConnection.EnumerateListener listener of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

String BrickletAccelerometer.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Accelerometer Bricklet.