Java - Accelerometer Bricklet – Tinkerforge

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# Java - Accelerometer Bricklet

Note

This Bricklet is currently in the prototype stage and the software/hardware as well as the documentation is in an incomplete state.

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

    public class ExampleSimple {
        private static final String HOST = "localhost";
        private static final int PORT = 4223;
        private static final String UID = "sad"; // Change to your UID

        // 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 acc = 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 a = acc.getAcceleration(); // Can throw com.tinkerforge.TimeoutException

            System.out.println("Acceleration(X): " + a.x / 1000.0 + "G");
            System.out.println("Acceleration(Y): " + a.y / 1000.0 + "G");
            System.out.println("Acceleration(Z): " + a.z / 1000.0 + "G");
            System.out.println("");

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

### Callback

Download (ExampleCallback.java)

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

    public class ExampleCallback {
        private static final String HOST = "localhost";
        private static final int PORT = 4223;
        private static final String UID = "sad"; // Change to your UID

        // 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 acc = new BrickletAccelerometer(UID, ipcon); // Create device object

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

            // 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!
            acc.setAccelerationCallbackPeriod(1000);

            // Add and implement acceleration listener (called if acceleration changes)
            acc.addAccelerationListener(new BrickletAccelerometer.AccelerationListener() {
                public void acceleration(short x, short y, short z) {
                    System.out.println("Accelerometer(X): " + x/1000.0 + "G");
                    System.out.println("Accelerometer(Y): " + y/1000.0 + "G");
                    System.out.println("Accelerometer(Z): " + z/1000.0 + "G");
                    System.out.println("");
                }
            });

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

### Threshold

Download (ExampleThreshold.java)

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

    public class ExampleThreshold {
        private static final String HOST = "localhost";
        private static final int PORT = 4223;
        private static final String UID = "sad"; // Change to your UID

        // 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 acc = 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)
            acc.setDebouncePeriod(10000);

            // Add and implement acceleration reached listener
            // Configure threshold for acceleration values X, Y or Z greater than 2G
            acc.setAccelerationCallbackThreshold('>', (short)2000, (short)0, (short)2000, (short)0, (short)2000, (short)0);

            acc.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("");
                }
            });

            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 `BrickletAccelerometer`(String uid, IPConnection ipcon)

  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).

public BrickletAccelerometer.Acceleration `getAcceleration`()

  Returns the acceleration in x, y and z direction. The values are given in mG (1/1000 G).

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

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

public short `getTemperature`()

  Returns the temperature of the accelerometer in °C.

public void `ledOn`()

  Enables the LED on the Bricklet.

public void `ledOff`()

  Disables the LED on the Bricklet.

public short `isLEDOn`()

  Returns true if the LED is enabled, false otherwise.

### Advanced Functions

public void `setConfiguration`(short dataRate, short fullScale, short filterBandwidth)

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

  - Data rate of 0Hz to 1600Hz.
  - Full scale range of -2G to +2G up to -16G to +16G.
  - Filter bandwidth between 50Hz and 800Hz.

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

  The default values are 100Hz data rate, -4G to +4G range and 200Hz filter bandwidth.

  The following constants are available for this function:

  - 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
  - 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
  - BrickletAccelerometer.FILTER_BANDWIDTH_800HZ = 0
  - BrickletAccelerometer.FILTER_BANDWIDTH_400HZ = 1
  - BrickletAccelerometer.FILTER_BANDWIDTH_200HZ = 2
  - BrickletAccelerometer.FILTER_BANDWIDTH_50HZ = 3

public BrickletAccelerometer.Configuration `getConfiguration`()

  Returns the configuration as set by `setConfiguration()`.

  The following constants are available for this function:

  - 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
  - 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
  - BrickletAccelerometer.FILTER_BANDWIDTH_800HZ = 0
  - BrickletAccelerometer.FILTER_BANDWIDTH_400HZ = 1
  - BrickletAccelerometer.FILTER_BANDWIDTH_200HZ = 2
  - BrickletAccelerometer.FILTER_BANDWIDTH_50HZ = 3

  The returned object has the public member variables `short dataRate`, `short fullScale` and `short filterBandwidth`.

public short[] `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`(short 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`(short 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 and listeners it is always disabled.

  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:

  - 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

public void `setResponseExpectedAll`(boolean responseExpected)

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

public BrickletAccelerometer.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`, `short[] hardwareVersion`, `short[] firmwareVersion` and `int deviceIdentifier`.

### Listener Configuration Functions

public void `setAccelerationCallbackPeriod`(long period)

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

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

  The default value is 0.

public long `getAccelerationCallbackPeriod`()

  Returns the period as set by `setAccelerationCallbackPeriod()`.

public void `setAccelerationCallbackThreshold`(char option, short minX, short maxX, short minY, short maxY, short minZ, short maxZ)

  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 temperature is outside the min and max values
  'i' | Listener is triggered when the temperature is inside the min and max values
  '<' | Listener is triggered when the temperature is smaller than the min value (max is ignored)
  '>' | Listener is triggered when the temperature is greater than the min value (max is ignored)

  The default value is ('x', 0, 0, 0, 0, 0, 0).

  The following constants are available for this function:

  - BrickletAccelerometer.THRESHOLD_OPTION_OFF = 'x'
  - BrickletAccelerometer.THRESHOLD_OPTION_OUTSIDE = 'o'
  - BrickletAccelerometer.THRESHOLD_OPTION_INSIDE = 'i'
  - BrickletAccelerometer.THRESHOLD_OPTION_SMALLER = '<'
  - BrickletAccelerometer.THRESHOLD_OPTION_GREATER = '>'

public BrickletAccelerometer.AccelerationCallbackThreshold `getAccelerationCallbackThreshold`()

  Returns the threshold as set by `setAccelerationCallbackThreshold()`.

  The following constants are available for this function:

  - BrickletAccelerometer.THRESHOLD_OPTION_OFF = 'x'
  - BrickletAccelerometer.THRESHOLD_OPTION_OUTSIDE = 'o'
  - BrickletAccelerometer.THRESHOLD_OPTION_INSIDE = 'i'
  - BrickletAccelerometer.THRESHOLD_OPTION_SMALLER = '<'
  - BrickletAccelerometer.THRESHOLD_OPTION_GREATER = '>'

  The returned object has the public member variables `char option`, `short minX`, `short maxX`, `short minY`, `short maxY`, `short minZ` and `short maxZ`.

public void `setDebouncePeriod`(long debounce)

  Sets the period in ms with which the threshold listener

  - `AccelerationReachedListener`

  is triggered, if the threshold

  - `setAccelerationCallbackThreshold()`

  keeps being reached.

  The default value is 100.

public long `getDebouncePeriod`()

  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.

public class `BrickletAccelerometer.AccelerationListener`()

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

  public void `acceleration`(short x, short y, short z)

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

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

public class `BrickletAccelerometer.AccelerationReachedListener`()

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

  public void `accelerationReached`(short x, short y, short z)

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

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

### Constants

public static final int `BrickletAccelerometer.DEVICE_IDENTIFIER`

  This constant is used to identify a Accelerometer Bricklet.

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

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