Java - DC Brick – Tinkerforge

- Getting Started
  - Primer
  - Tutorials
  - FAQ
- Hardware
  - Bricks
  - Bricklets
  - Master Extensions
  - Power Supplies
  - Accessories
  - Timeline
- Software
  - Brick Daemon (brickd)
  - Brick Viewer (brickv)
  - API Bindings
    - C/C++
    - C/C++ (iOS)
    - C#
    - C# (Windows Phone)
    - Delphi/Lazarus
    - Java
      - Requirements
      - Installation
      - Testing an Example
      - API Reference and Examples
        - IP Connection
        - Bricks
          - DC Brick
            - Examples
              - Configuration
              - Callback
            - API
              - Basic Functions
              - Advanced Functions
              - Listener Configuration Functions
              - Listeners
              - Constants
          - IMU Brick
          - Master Brick
          - RED Brick
          - Servo Brick
          - Stepper Brick
        - Bricklets
    - Java (Android)
    - JavaScript
    - LabVIEW
    - Mathematica
    - MATLAB/Octave
    - Perl
    - PHP
    - Python
    - Ruby
    - Shell
    - Visual Basic .NET
  - Firmwares and Plugins
  - Device Identifier
  - Source Code and Bug Tracking
  - Programming Interface
- Starter Kits
  - Weather Station
  - Hardware Hacking
  - Server Room Monitoring
  - Blinkenlights
  - Internet of Things
  - Camera Slider
- Embedded Boards
  - Raspberry Pi
- Specifications
  - Technical Data
  - TCP/IP Protocol
  - Modbus Protocol
  - Wireshark Dissector

# Java - DC Brick

This is the description of the Java API bindings for the DC Brick. General information and technical specifications for the DC Brick 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).

### Configuration

Download (ExampleConfiguration.java)

     1
     2
     3
     4
     5
     6
     7
     8
     9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29

    import com.tinkerforge.BrickDC;
    import com.tinkerforge.IPConnection;

    public class ExampleConfiguration {
        private static final String HOST = "localhost";
        private static final int PORT = 4223;
        private static final String UID = "aetiNB3mX2u"; // 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
            BrickDC dc = new BrickDC(UID, ipcon); // Create device object

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

            dc.setPWMFrequency(10000); // Use PWM frequency of 10kHz
            dc.setDriveMode((short)1); // Use 1 = Drive/Coast instead of 0 = Drive/Brake

            dc.enable();
            dc.setAcceleration(5000); // Slow acceleration
            dc.setVelocity((short)32767); // Full speed forward

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

### Callback

Download (ExampleCallback.java)

     1
     2
     3
     4
     5
     6
     7
     8
     9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    52
    53
    54
    55

    import com.tinkerforge.BrickDC;
    import com.tinkerforge.IPConnection;
    import com.tinkerforge.TimeoutException;
    import com.tinkerforge.NotConnectedException;

    public class ExampleCallback {
        private static final String HOST = "localhost";
        private static final int PORT = 4223;
        private static final String UID = "aetiNB3mX2u"; // 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
            // Note: Declare servo final, so the listener can access it
            final BrickDC dc = new BrickDC(UID, ipcon); // Create device object

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

            // Add and implement velocity reached listener
            // (called if velocity set by setVelocity is reached)
            dc.addVelocityReachedListener(new BrickDC.VelocityReachedListener() {
                public void velocityReached(short velocity) {
                    if(velocity == 32767) {
                        System.out.println("Velocity: Full Speed forward, turning backward");
                        try {
                            dc.setVelocity((short)-32767);
                        } catch(TimeoutException e) {
                        } catch(NotConnectedException e) {
                        }
                    } else if(velocity == -32767) {
                        System.out.println("Velocity: Full Speed backward, turning forward");
                        try {
                            dc.setVelocity((short)32767);
                        } catch(TimeoutException e) {
                        } catch(NotConnectedException e) {
                        }
                    } else {
                        System.out.println("Error"); // Can only happen if another program sets velocity
                    }
                }
            });

            dc.enable();
            // The acceleration has to be smaller or equal to the maximum acceleration
            // of the DC motor, otherwise the velocity reached listener will be called too early
            dc.setAcceleration(5000); // Slow acceleration
            dc.setVelocity((short)32767); // Full speed forward

            System.out.println("Press key to exit"); System.in.read();
            dc.disable();
            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 `BrickDC`(String uid, IPConnection ipcon)

  Creates an object with the unique device ID `uid`:

      BrickDC dc = new BrickDC("YOUR_DEVICE_UID", ipcon);

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

public void `setVelocity`(short velocity)

  Sets the velocity of the motor. Whereas -32767 is full speed backward, 0 is stop and 32767 is full speed forward. Depending on the acceleration (see `setAcceleration()`), the motor is not immediately brought to the velocity but smoothly accelerated.

  The velocity describes the duty cycle of the PWM with which the motor is controlled, e.g. a velocity of 3277 sets a PWM with a 10% duty cycle. You can not only control the duty cycle of the PWM but also the frequency, see `setPWMFrequency()`.

  The default velocity is 0.

public short `getVelocity`()

  Returns the velocity as set by `setVelocity()`.

public short `getCurrentVelocity`()

  Returns the current velocity of the motor. This value is different from `getVelocity()` whenever the motor is currently accelerating to a goal set by `setVelocity()`.

public void `setAcceleration`(int acceleration)

  Sets the acceleration of the motor. It is given in velocity/s. An acceleration of 10000 means, that every second the velocity is increased by 10000 (or about 30% duty cycle).

  For example: If the current velocity is 0 and you want to accelerate to a velocity of 16000 (about 50% duty cycle) in 10 seconds, you should set an acceleration of 1600.

  If acceleration is set to 0, there is no speed ramping, i.e. a new velocity is immediately given to the motor.

  The default acceleration is 10000.

public int `getAcceleration`()

  Returns the acceleration as set by `setAcceleration()`.

public void `fullBrake`()

  Executes an active full brake.

  Warning

  This function is for emergency purposes, where an immediate brake is necessary. Depending on the current velocity and the strength of the motor, a full brake can be quite violent.

  Call `setVelocity()` with 0 if you just want to stop the motor.

public void `enable`()

  Enables the driver chip. The driver parameters can be configured (velocity, acceleration, etc) before it is enabled.

public void `disable`()

  Disables the driver chip. The configurations are kept (velocity, acceleration, etc) but the motor is not driven until it is enabled again.

public boolean `isEnabled`()

  Returns true if the driver chip is enabled, false otherwise.

### Advanced Functions

public void `setPWMFrequency`(int frequency)

  Sets the frequency (in Hz) of the PWM with which the motor is driven. The possible range of the frequency is 1-20000Hz. Often a high frequency is less noisy and the motor runs smoother. However, with a low frequency there are less switches and therefore fewer switching losses. Also with most motors lower frequencies enable higher torque.

  If you have no idea what all this means, just ignore this function and use the default frequency, it will very likely work fine.

  The default frequency is 15 kHz.

public int `getPWMFrequency`()

  Returns the PWM frequency (in Hz) as set by `setPWMFrequency()`.

public int `getStackInputVoltage`()

  Returns the stack input voltage in mV. The stack input voltage is the voltage that is supplied via the stack, i.e. it is given by a Step-Down or Step-Up Power Supply.

public int `getExternalInputVoltage`()

  Returns the external input voltage in mV. The external input voltage is given via the black power input connector on the DC Brick.

  If there is an external input voltage and a stack input voltage, the motor will be driven by the external input voltage. If there is only a stack voltage present, the motor will be driven by this voltage.

  Warning

  This means, if you have a high stack voltage and a low external voltage, the motor will be driven with the low external voltage. If you then remove the external connection, it will immediately be driven by the high stack voltage.

public int `getCurrentConsumption`()

  Returns the current consumption of the motor in mA.

public void `setDriveMode`(short mode)

  Sets the drive mode. Possible modes are:

  - 0 = Drive/Brake
  - 1 = Drive/Coast

  These modes are different kinds of motor controls.

  In Drive/Brake mode, the motor is always either driving or braking. There is no freewheeling. Advantages are: A more linear correlation between PWM and velocity, more exact accelerations and the possibility to drive with slower velocities.

  In Drive/Coast mode, the motor is always either driving or freewheeling. Advantages are: Less current consumption and less demands on the motor and driver chip.

  The default value is 0 = Drive/Brake.

  The following constants are available for this function:

  - BrickDC.DRIVE_MODE_DRIVE_BRAKE = 0
  - BrickDC.DRIVE_MODE_DRIVE_COAST = 1

public short `getDriveMode`()

  Returns the drive mode, as set by `setDriveMode()`.

  The following constants are available for this function:

  - BrickDC.DRIVE_MODE_DRIVE_BRAKE = 0
  - BrickDC.DRIVE_MODE_DRIVE_COAST = 1

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:

  - BrickDC.FUNCTION_SET_VELOCITY = 1
  - BrickDC.FUNCTION_SET_ACCELERATION = 4
  - BrickDC.FUNCTION_SET_PWM_FREQUENCY = 6
  - BrickDC.FUNCTION_FULL_BRAKE = 8
  - BrickDC.FUNCTION_ENABLE = 12
  - BrickDC.FUNCTION_DISABLE = 13
  - BrickDC.FUNCTION_SET_MINIMUM_VOLTAGE = 15
  - BrickDC.FUNCTION_SET_DRIVE_MODE = 17
  - BrickDC.FUNCTION_SET_CURRENT_VELOCITY_PERIOD = 19
  - BrickDC.FUNCTION_ENABLE_STATUS_LED = 238
  - BrickDC.FUNCTION_DISABLE_STATUS_LED = 239
  - BrickDC.FUNCTION_RESET = 243

public void `setResponseExpectedAll`(boolean responseExpected)

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

public void `enableStatusLED`()

  Enables the status LED.

  The status LED is the blue LED next to the USB connector. If enabled is is on and it flickers if data is transfered. If disabled it is always off.

  The default state is enabled.

  New in version 2.3.1 (Firmware).

public void `disableStatusLED`()

  Disables the status LED.

  The status LED is the blue LED next to the USB connector. If enabled is is on and it flickers if data is transfered. If disabled it is always off.

  The default state is enabled.

  New in version 2.3.1 (Firmware).

public boolean `isStatusLEDEnabled`()

  Returns true if the status LED is enabled, false otherwise.

  New in version 2.3.1 (Firmware).

public BrickDC.Protocol1BrickletName `getProtocol1BrickletName`(char port)

  Returns the firmware and protocol version and the name of the Bricklet for a given port.

  This functions sole purpose is to allow automatic flashing of v1.x.y Bricklet plugins.

  The returned object has the public member variables `short protocolVersion`, `short[] firmwareVersion` and `String name`.

public short `getChipTemperature`()

  Returns the temperature in °C/10 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 an accuracy of +-15%. Practically it is only useful as an indicator for temperature changes.

public void `reset`()

  Calling this function will reset the Brick. Calling this function on a Brick inside of a stack will reset the whole stack.

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

public BrickDC.Identity `getIdentity`()

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

  The position can be '0'-'8' (stack position).

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

  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 `setMinimumVoltage`(int voltage)

  Sets the minimum voltage in mV, below which the `UnderVoltageListener` listener is triggered. The minimum possible value that works with the DC Brick is 6V. You can use this function to detect the discharge of a battery that is used to drive the motor. If you have a fixed power supply, you likely do not need this functionality.

  The default value is 6V.

public int `getMinimumVoltage`()

  Returns the minimum voltage as set by `setMinimumVoltage()`

public void `setCurrentVelocityPeriod`(int period)

  Sets a period in ms with which the `CurrentVelocityListener` listener is triggered. A period of 0 turns the listener off.

  The default value is 0.

public int `getCurrentVelocityPeriod`()

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

### 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 BrickDC.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 `BrickDC.UnderVoltageListener`()

  This listener can be added with the `addUnderVoltageListener()` function. An added listener can be removed with the `removeUnderVoltageListener()` function.

  public void `underVoltage`(int voltage)

    This listener is triggered when the input voltage drops below the value set by `setMinimumVoltage()`. The parameter is the current voltage given in mV.

public class `BrickDC.EmergencyShutdownListener`()

  This listener can be added with the `addEmergencyShutdownListener()` function. An added listener can be removed with the `removeEmergencyShutdownListener()` function.

  public void `emergencyShutdown`()

    This listener is triggered if either the current consumption is too high (above 5A) or the temperature of the driver chip is too high (above 175°C). These two possibilities are essentially the same, since the temperature will reach this threshold immediately if the motor consumes too much current. In case of a voltage below 3.3V (external or stack) this listener is triggered as well.

    If this listener is triggered, the driver chip gets disabled at the same time. That means, `enable()` has to be called to drive the motor again.

    Note

    This listener only works in Drive/Brake mode (see `setDriveMode()`). In Drive/Coast mode it is unfortunately impossible to reliably read the overcurrent/overtemperature signal from the driver chip.

public class `BrickDC.VelocityReachedListener`()

  This listener can be added with the `addVelocityReachedListener()` function. An added listener can be removed with the `removeVelocityReachedListener()` function.

  public void `velocityReached`(short velocity)

    This listener is triggered whenever a set velocity is reached. For example: If a velocity of 0 is present, acceleration is set to 5000 and velocity to 10000, `VelocityReachedListener` will be triggered after about 2 seconds, when the set velocity is actually reached.

    Note

    Since we can't get any feedback from the DC motor, this only works if the acceleration (see `setAcceleration()`) is set smaller or equal to the maximum acceleration of the motor. Otherwise the motor will lag behind the control value and the listener will be triggered too early.

public class `BrickDC.CurrentVelocityListener`()

  This listener can be added with the `addCurrentVelocityListener()` function. An added listener can be removed with the `removeCurrentVelocityListener()` function.

  public void `currentVelocity`(short velocity)

    This listener is triggered with the period that is set by `setCurrentVelocityPeriod()`. The parameter is the current velocity used by the motor.

    `CurrentVelocityListener` is only triggered after the set period if there is a change in the velocity.

### Constants

public static final int `BrickDC.DEVICE_IDENTIFIER`

  This constant is used to identify a DC Brick.

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

The content of this page is licensed under Creative Commons Attribution 3.0 Unported License.