Java - Accelerometer Bricklet 2.0

This is the description of the Java API bindings for the Accelerometer Bricklet 2.0. General information and technical specifications for the Accelerometer Bricklet 2.0 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.BrickletAccelerometerV2;
import com.tinkerforge.BrickletAccelerometerV2.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 2.0
    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
        BrickletAccelerometerV2 a =
          new BrickletAccelerometerV2(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/10000.0 + " g");
        System.out.println("Acceleration [Y]: " + acceleration.y/10000.0 + " g");
        System.out.println("Acceleration [Z]: " + acceleration.z/10000.0 + " 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.BrickletAccelerometerV2;

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

    // Change XYZ to the UID of your Accelerometer Bricklet 2.0
    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
        BrickletAccelerometerV2 a =
          new BrickletAccelerometerV2(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 BrickletAccelerometerV2.AccelerationListener() {
            public void acceleration(int x, int y, int z) {
                System.out.println("Acceleration [X]: " + x/10000.0 + " g");
                System.out.println("Acceleration [Y]: " + y/10000.0 + " g");
                System.out.println("Acceleration [Z]: " + z/10000.0 + " g");
                System.out.println("");
            }
        });

        // Set period for acceleration callback to 1s (1000ms)
        a.setAccelerationCallbackConfiguration(1000, false);

        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

public class BrickletAccelerometerV2(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid:

BrickletAccelerometerV2 accelerometerV2 = new BrickletAccelerometerV2("YOUR_DEVICE_UID", ipcon);

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

public BrickletAccelerometerV2.Acceleration getAcceleration()

Returns the acceleration in x, y and z direction. The values are given in g/10000 (1g = 9.80665m/s²), not to be confused with grams.

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

The returned object has the public member variables int x, int y and int z.

public void setConfiguration(int dataRate, int fullScale)

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

  • Data rate of 0.781Hz to 25600Hz.
  • Full scale range of -2g to +2g up to -8g to +8g.

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

The default values are 100Hz data rate and -2g to +2g range.

The following constants are available for this function:

  • BrickletAccelerometerV2.DATA_RATE_0_781HZ = 0
  • BrickletAccelerometerV2.DATA_RATE_1_563HZ = 1
  • BrickletAccelerometerV2.DATA_RATE_3_125HZ = 2
  • BrickletAccelerometerV2.DATA_RATE_6_2512HZ = 3
  • BrickletAccelerometerV2.DATA_RATE_12_5HZ = 4
  • BrickletAccelerometerV2.DATA_RATE_25HZ = 5
  • BrickletAccelerometerV2.DATA_RATE_50HZ = 6
  • BrickletAccelerometerV2.DATA_RATE_100HZ = 7
  • BrickletAccelerometerV2.DATA_RATE_200HZ = 8
  • BrickletAccelerometerV2.DATA_RATE_400HZ = 9
  • BrickletAccelerometerV2.DATA_RATE_800HZ = 10
  • BrickletAccelerometerV2.DATA_RATE_1600HZ = 11
  • BrickletAccelerometerV2.DATA_RATE_3200HZ = 12
  • BrickletAccelerometerV2.DATA_RATE_6400HZ = 13
  • BrickletAccelerometerV2.DATA_RATE_12800HZ = 14
  • BrickletAccelerometerV2.DATA_RATE_25600HZ = 15
  • BrickletAccelerometerV2.FULL_SCALE_2G = 0
  • BrickletAccelerometerV2.FULL_SCALE_4G = 1
  • BrickletAccelerometerV2.FULL_SCALE_8G = 2
public BrickletAccelerometerV2.Configuration getConfiguration()

Returns the configuration as set by setConfiguration().

The following constants are available for this function:

  • BrickletAccelerometerV2.DATA_RATE_0_781HZ = 0
  • BrickletAccelerometerV2.DATA_RATE_1_563HZ = 1
  • BrickletAccelerometerV2.DATA_RATE_3_125HZ = 2
  • BrickletAccelerometerV2.DATA_RATE_6_2512HZ = 3
  • BrickletAccelerometerV2.DATA_RATE_12_5HZ = 4
  • BrickletAccelerometerV2.DATA_RATE_25HZ = 5
  • BrickletAccelerometerV2.DATA_RATE_50HZ = 6
  • BrickletAccelerometerV2.DATA_RATE_100HZ = 7
  • BrickletAccelerometerV2.DATA_RATE_200HZ = 8
  • BrickletAccelerometerV2.DATA_RATE_400HZ = 9
  • BrickletAccelerometerV2.DATA_RATE_800HZ = 10
  • BrickletAccelerometerV2.DATA_RATE_1600HZ = 11
  • BrickletAccelerometerV2.DATA_RATE_3200HZ = 12
  • BrickletAccelerometerV2.DATA_RATE_6400HZ = 13
  • BrickletAccelerometerV2.DATA_RATE_12800HZ = 14
  • BrickletAccelerometerV2.DATA_RATE_25600HZ = 15
  • BrickletAccelerometerV2.FULL_SCALE_2G = 0
  • BrickletAccelerometerV2.FULL_SCALE_4G = 1
  • BrickletAccelerometerV2.FULL_SCALE_8G = 2

The returned object has the public member variables int dataRate and int fullScale.

public void setInfoLEDConfig(int config)

Configures the info LED (marked as "Force" on the Bricklet) to be either turned off, turned on, or blink in heartbeat mode.

The following constants are available for this function:

  • BrickletAccelerometerV2.INFO_LED_CONFIG_OFF = 0
  • BrickletAccelerometerV2.INFO_LED_CONFIG_ON = 1
  • BrickletAccelerometerV2.INFO_LED_CONFIG_SHOW_HEARTBEAT = 2
public int getInfoLEDConfig()

Returns the LED configuration as set by setInfoLEDConfig()

The following constants are available for this function:

  • BrickletAccelerometerV2.INFO_LED_CONFIG_OFF = 0
  • BrickletAccelerometerV2.INFO_LED_CONFIG_ON = 1
  • BrickletAccelerometerV2.INFO_LED_CONFIG_SHOW_HEARTBEAT = 2
public void setContinuousAccelerationConfiguration(boolean enableX, boolean enableY, boolean enableZ, int resolution)

For high throughput of acceleration data (> 1000Hz) you have to use the ContinuousAcceleration16BitListener or ContinuousAcceleration8BitListener callbacks.

You can enable the listener for each axis (x, y, z) individually and choose a resolution of 8 bit or 16 bit.

If at least one of the axis is enabled and the resolution is set to 8 bit, the ContinuousAcceleration8BitListener listener is activated. If at least one of the axis is enabled and the resolution is set to 16 bit, the ContinuousAcceleration16BitListener listener is activated.

If a resolution of 8 bit is used, only the 8 most significant bits will be transferred. This means that the unit changes from g/10000 to g*256/10000.

If no axis is enabled, both listeners are disabled. If one of the continuous callbacks is enabled, the AccelerationListener listener is disabled.

The maximum throughput depends on the exact configuration:

Number of axis enabled Throughput 8 bit Throughout 16 bit
1 25600Hz 25600Hz
2 25600Hz 15000Hz
3 20000Hz 10000Hz

The following constants are available for this function:

  • BrickletAccelerometerV2.RESOLUTION_8BIT = 0
  • BrickletAccelerometerV2.RESOLUTION_16BIT = 1
public BrickletAccelerometerV2.ContinuousAccelerationConfiguration getContinuousAccelerationConfiguration()

Returns the continuous acceleration configuration as set by setContinuousAccelerationConfiguration().

The following constants are available for this function:

  • BrickletAccelerometerV2.RESOLUTION_8BIT = 0
  • BrickletAccelerometerV2.RESOLUTION_16BIT = 1

The returned object has the public member variables boolean enableX, boolean enableY, boolean enableZ and int resolution.

Advanced Functions

public int[] getAPIVersion()

Returns the version of the API definition (major, minor, revision) 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.

public boolean getResponseExpected(int functionId)

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.

See setResponseExpected() for the list of function ID constants available for this function.

public void setResponseExpected(int functionId, boolean responseExpected)

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 function ID constants are available for this function:

  • BrickletAccelerometerV2.FUNCTION_SET_CONFIGURATION = 2
  • BrickletAccelerometerV2.FUNCTION_SET_ACCELERATION_CALLBACK_CONFIGURATION = 4
  • BrickletAccelerometerV2.FUNCTION_SET_INFO_LED_CONFIG = 6
  • BrickletAccelerometerV2.FUNCTION_SET_CONTINUOUS_ACCELERATION_CONFIGURATION = 9
  • BrickletAccelerometerV2.FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletAccelerometerV2.FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletAccelerometerV2.FUNCTION_RESET = 243
  • BrickletAccelerometerV2.FUNCTION_WRITE_UID = 248
public void setResponseExpectedAll(boolean responseExpected)

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

public BrickletAccelerometerV2.SPITFPErrorCount getSPITFPErrorCount()

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

The returned object has the public member variables long errorCountAckChecksum, long errorCountMessageChecksum, long errorCountFrame and long errorCountOverflow.

public int setBootloaderMode(int mode)

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following constants are available for this function:

  • BrickletAccelerometerV2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletAccelerometerV2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletAccelerometerV2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletAccelerometerV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletAccelerometerV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BrickletAccelerometerV2.BOOTLOADER_STATUS_OK = 0
  • BrickletAccelerometerV2.BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletAccelerometerV2.BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletAccelerometerV2.BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletAccelerometerV2.BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletAccelerometerV2.BOOTLOADER_STATUS_CRC_MISMATCH = 5
public int getBootloaderMode()

Returns the current bootloader mode, see setBootloaderMode().

The following constants are available for this function:

  • BrickletAccelerometerV2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletAccelerometerV2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletAccelerometerV2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletAccelerometerV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletAccelerometerV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
public void setWriteFirmwarePointer(long pointer)

Sets the firmware pointer for writeFirmware(). The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

public int writeFirmware(int[] data)

Writes 64 Bytes of firmware at the position as written by setWriteFirmwarePointer() before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

public void setStatusLEDConfig(int config)

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following constants are available for this function:

  • BrickletAccelerometerV2.STATUS_LED_CONFIG_OFF = 0
  • BrickletAccelerometerV2.STATUS_LED_CONFIG_ON = 1
  • BrickletAccelerometerV2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletAccelerometerV2.STATUS_LED_CONFIG_SHOW_STATUS = 3
public int getStatusLEDConfig()

Returns the configuration as set by setStatusLEDConfig()

The following constants are available for this function:

  • BrickletAccelerometerV2.STATUS_LED_CONFIG_OFF = 0
  • BrickletAccelerometerV2.STATUS_LED_CONFIG_ON = 1
  • BrickletAccelerometerV2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletAccelerometerV2.STATUS_LED_CONFIG_SHOW_STATUS = 3
public int getChipTemperature()

Returns the temperature in °C as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

public void reset()

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

public void writeUID(long uid)

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

public long readUID()

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

public BrickletAccelerometerV2.Identity getIdentity()

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' or 'd'.

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

The returned object has the public member variables String uid, String connectedUid, char position, int[] hardwareVersion, int[] firmwareVersion and int deviceIdentifier.

Listener Configuration Functions

public void setAccelerationCallbackConfiguration(long period, boolean valueHasToChange)

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

If the value has to change-parameter is set to true, the listener is only triggered after the value has changed. If the value didn't change within the period, the listener is triggered immediately on change.

If it is set to false, the listener is continuously triggered with the period, independent of the value.

If this listener is enabled, the ContinuousAcceleration16BitListener listener and ContinuousAcceleration8BitListener listener will automatically be disabled.

The default value is (0, false).

public BrickletAccelerometerV2.AccelerationCallbackConfiguration getAccelerationCallbackConfiguration()

Returns the listener configuration as set by setAccelerationCallbackConfiguration().

The returned object has the public member variables long period and boolean valueHasToChange.

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 BrickletAccelerometerV2.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.

public class BrickletAccelerometerV2.AccelerationListener()

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

public void acceleration(int x, int y, int z)

This listener is triggered periodically according to the configuration set by setAccelerationCallbackConfiguration().

The parameters are the same as getAcceleration().

public class BrickletAccelerometerV2.ContinuousAcceleration16BitListener()

This listener can be added with the addContinuousAcceleration16BitListener() function. An added listener can be removed with the removeContinuousAcceleration16BitListener() function.

public void continuousAcceleration16Bit(int[] acceleration)

Returns 30 acceleration values with 16 bit resolution. The data rate can be configured with setConfiguration() and this listener can be enabled with setContinuousAccelerationConfiguration().

The unit of the values is g/10000.

The data is formated in the sequence "x, y, z, x, y, z, ..." depending on the enabled axis. Examples:

  • x, y, z enabled: "x, y, z, ... 10x ..., x, y, z"
  • x, z enabled: "x, z, ... 15x ..., x, z"
  • y enabled: "y, ... 30x ..., y"
public class BrickletAccelerometerV2.ContinuousAcceleration8BitListener()

This listener can be added with the addContinuousAcceleration8BitListener() function. An added listener can be removed with the removeContinuousAcceleration8BitListener() function.

public void continuousAcceleration8Bit(int[] acceleration)

Returns 30 acceleration values with 8 bit resolution. The data rate can be configured with setConfiguration() and this listener can be enabled with setContinuousAccelerationConfiguration().

The unit of the values is g*256/10000.

The data is formated in the sequence "x, y, z, x, y, z, ..." depending on the enabled axis. Examples:

  • x, y, z enabled: "x, y, z, ... 20x ..., x, y, z"
  • x, z enabled: "x, z, ... 30x ..., x, z"
  • y enabled: "y, ... 60x ..., y"

Constants

public static final int BrickletAccelerometerV2.DEVICE_IDENTIFIER

This constant is used to identify a Accelerometer Bricklet 2.0.

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

public static final String BrickletAccelerometerV2.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Accelerometer Bricklet 2.0.