This is the description of the Java API bindings for the LED Strip Bricklet. General information and technical specifications for the LED Strip Bricklet are summarized in its hardware description.
An installation guide for the Java API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
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 | import com.tinkerforge.BrickletLEDStrip;
import com.tinkerforge.IPConnection;
public class ExampleSimple {
private static final String HOST = "localhost";
private static final int PORT = 4223;
private static final String UID = "XYZ"; // 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
BrickletLEDStrip ledStrip = new BrickletLEDStrip(UID, ipcon); // Create device object
ipcon.connect(HOST, PORT); // Connect to brickd
// Don't use device before ipcon is connected
// Set first 10 LEDs to green
short[] r = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
short[] g = {255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 0, 0, 0, 0, 0, 0};
short[] b = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
ledStrip.setRGBValues(0, (short)10, r, g, b);
System.out.println("Press key to exit"); System.in.read();
ipcon.disconnect();
}
}
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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 | import com.tinkerforge.BrickletLEDStrip;
import com.tinkerforge.IPConnection;
public class ExampleCallback {
private static final String HOST = "localhost";
private static final int PORT = 4223;
private static final String UID = "XYZ"; // Change to your UID
private static final int NUM_LEDS = 16;
private static int rIndex = 0;
private static short[] r = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
private static short[] g = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
private static short[] b = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
// 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
final BrickletLEDStrip ledStrip = new BrickletLEDStrip(UID, ipcon); // Create device object
ipcon.connect(HOST, PORT); // Connect to brickd
// Don't use device before ipcon is connected
// Frame rendered callback, is called when a new frame was rendered
// We increase the index of one blue LED with every frame
ledStrip.addFrameRenderedListener(new BrickletLEDStrip.FrameRenderedListener() {
public void frameRendered(int length) {
b[rIndex] = 0;
if(rIndex == NUM_LEDS-1) {
rIndex = 0;
} else {
rIndex++;
}
b[rIndex] = 255;
// Set new data for next render cycle
try {
ledStrip.setRGBValues(0, (short)NUM_LEDS, r, g, b);
} catch(Exception e) {
System.out.println(e);
}
}
});
// Set frame duration to 50ms (20 frames per second)
ledStrip.setFrameDuration(50);
// Set initial rgb values to get started
ledStrip.setRGBValues(0, (short)NUM_LEDS, r, g, b);
System.out.println("Press key to exit"); System.in.read();
ipcon.disconnect();
}
}
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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.
Creates an object with the unique device ID uid:
BrickletLEDStrip ledStrip = new BrickletLEDStrip("YOUR_DEVICE_UID", ipcon);
This object can then be used after the IP Connection is connected (see examples above).
Sets the rgb values for the LEDs with the given length starting from index.
The maximum length is 16, the index goes from 0 to 319 and the rgb values have 8 bits each.
Example: If you set
the LED with index 5 will be red, 6 will be green and 7 will be blue.
Note
Depending on the LED circuitry colors can be permuted.
The colors will be transfered to actual LEDs when the next frame duration ends, see setFrameDuration().
Generic approach:
This approach ensures that you can change the LED colors with a fixed frame rate.
The actual number of controllable LEDs depends on the number of free Bricklet ports. See here for more information. A call of setRGBValues() with index + length above the bounds is ignored completely.
Returns the rgb with the given length starting from the given index.
The values are the last values that were set by setRGBValues().
The returned object has the public member variables short[] r, short[] g and short[] b.
Sets the frame duration in ms.
Example: If you want to achieve 20 frames per second, you should set the frame duration to 50ms (50ms * 20 = 1 second).
For an explanation of the general approach see setRGBValues().
Default value: 100ms (10 frames per second).
Returns the frame duration as set by setFrameDuration().
Returns the current supply voltage of the LEDs. The voltage is given in mV.
Sets the frequency of the clock in Hz. The range is 10000Hz (10kHz) up to 2000000Hz (2MHz).
The Bricklet will choose the nearest achievable frequency, which may be off by a few Hz. You can get the exact frequency that is used by calling getClockFrequency().
If you have problems with flickering LEDs, they may be bits flipping. You can fix this by either making the connection between the LEDs and the Bricklet shorter or by reducing the frequency.
With a decreasing frequency your maximum frames per second will decrease too.
The default value is 1.66MHz.
Note
The frequency in firmware version 2.0.0 is fixed at 2MHz.
New in version 2.0.1 (Plugin).
Returns the currently used clock frequency as set by setClockFrequency().
New in version 2.0.1 (Plugin).
Sets the type of the led driver chip. We currently support the chips
The WS2812 is sometimes also called "NeoPixel", a name coined by Adafruit.
The default value is WS2801 (chip = 2801).
The following constants are available for this function:
New in version 2.0.2 (Plugin).
Returns the currently used chip type as set by setChipType().
The following constants are available for this function:
New in version 2.0.2 (Plugin).
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.
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.
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:
Changes the response expected flag for all setter and listener configuration functions of this device at once.
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.
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 BrickletLEDStrip.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.
This listener can be added with the addFrameRenderedListener() function. An added listener can be removed with the removeFrameRenderedListener() function.
This listener is triggered directly after a new frame is rendered.
You should send the data for the next frame directly after this listener was triggered.
For an explanation of the general approach see setRGBValues().
This constant is used to identify a LED Strip 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.