This is the description of the Java API bindings for the Laser Range Finder Bricklet 2.0. General information and technical specifications for the Laser Range Finder Bricklet 2.0 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 28 29 30 31 32 33 34 35 36 | import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletLaserRangeFinderV2;
public class ExampleSimple {
private static final String HOST = "localhost";
private static final int PORT = 4223;
// Change XYZ to the UID of your Laser Range Finder 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
BrickletLaserRangeFinderV2 lrf =
new BrickletLaserRangeFinderV2(UID, ipcon); // Create device object
ipcon.connect(HOST, PORT); // Connect to brickd
// Don't use device before ipcon is connected
// Turn laser on and wait 250ms for very first measurement to be ready
lrf.setEnable(true);
Thread.sleep(250);
// Get current distance
int distance = lrf.getDistance(); // Can throw com.tinkerforge.TimeoutException
System.out.println("Distance: " + distance + " cm");
System.out.println("Press key to exit"); System.in.read();
// Turn laser off
lrf.setEnable(false);
ipcon.disconnect();
}
}
|
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 | import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletLaserRangeFinderV2;
public class ExampleCallback {
private static final String HOST = "localhost";
private static final int PORT = 4223;
// Change XYZ to the UID of your Laser Range Finder 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
BrickletLaserRangeFinderV2 lrf =
new BrickletLaserRangeFinderV2(UID, ipcon); // Create device object
ipcon.connect(HOST, PORT); // Connect to brickd
// Don't use device before ipcon is connected
// Turn laser on and wait 250ms for very first measurement to be ready
lrf.setEnable(true);
Thread.sleep(250);
// Add distance listener
lrf.addDistanceListener(new BrickletLaserRangeFinderV2.DistanceListener() {
public void distance(int distance) {
System.out.println("Distance: " + distance + " cm");
}
});
// Set period for distance callback to 0.2s (200ms) without a threshold
lrf.setDistanceCallbackConfiguration(200, false, 'x', 0, 0);
System.out.println("Press key to exit"); System.in.read();
// Turn laser off
lrf.setEnable(false);
ipcon.disconnect();
}
}
|
Download (ExampleThreshold.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 | import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletLaserRangeFinderV2;
public class ExampleThreshold {
private static final String HOST = "localhost";
private static final int PORT = 4223;
// Change XYZ to the UID of your Laser Range Finder 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
BrickletLaserRangeFinderV2 lrf =
new BrickletLaserRangeFinderV2(UID, ipcon); // Create device object
ipcon.connect(HOST, PORT); // Connect to brickd
// Don't use device before ipcon is connected
// Turn laser on and wait 250ms for very first measurement to be ready
lrf.setEnable(true);
Thread.sleep(250);
// Add distance listener
lrf.addDistanceListener(new BrickletLaserRangeFinderV2.DistanceListener() {
public void distance(int distance) {
System.out.println("Distance: " + distance + " cm");
}
});
// Configure threshold for distance "greater than 20 cm"
// with a debounce period of 1s (1000ms)
lrf.setDistanceCallbackConfiguration(1000, false, '>', 20, 0);
System.out.println("Press key to exit"); System.in.read();
// Turn laser off
lrf.setEnable(false);
ipcon.disconnect();
}
}
|
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.
BrickletLaserRangeFinderV2
(String uid, IPConnection ipcon)¶Parameters: |
|
---|---|
Returns: |
|
Creates an object with the unique device ID uid
:
BrickletLaserRangeFinderV2 laserRangeFinderV2 = new BrickletLaserRangeFinderV2("YOUR_DEVICE_UID", ipcon);
This object can then be used after the IP Connection is connected.
BrickletLaserRangeFinderV2.
getDistance
()¶Returns: |
|
---|
Returns the measured distance.
The laser has to be enabled, see setEnable()
.
If you want to get the value periodically, it is recommended to use the
DistanceListener
listener. You can set the listener configuration
with setDistanceCallbackConfiguration()
.
BrickletLaserRangeFinderV2.
getVelocity
()¶Returns: |
|
---|
Returns the measured velocity. The value has a range of -12800 to 12700 and is given in 1/100 m/s.
The velocity measurement only produces stables results if a fixed
measurement rate (see setConfiguration()
) is configured. Also the laser
has to be enabled, see setEnable()
.
If you want to get the value periodically, it is recommended to use the
VelocityListener
listener. You can set the listener configuration
with setVelocityCallbackConfiguration()
.
BrickletLaserRangeFinderV2.
setEnable
(boolean enable)¶Parameters: |
|
---|
Enables the laser of the LIDAR if set to true.
We recommend that you wait 250ms after enabling the laser before
the first call of getDistance()
to ensure stable measurements.
BrickletLaserRangeFinderV2.
getEnable
()¶Returns: |
|
---|
Returns the value as set by setEnable()
.
BrickletLaserRangeFinderV2.
setConfiguration
(int acquisitionCount, boolean enableQuickTermination, int thresholdValue, int measurementFrequency)¶Parameters: |
|
---|
The Acquisition Count defines the number of times the Laser Range Finder Bricklet will integrate acquisitions to find a correlation record peak. With a higher count, the Bricklet can measure longer distances. With a lower count, the rate increases. The allowed values are 1-255.
If you set Enable Quick Termination to true, the distance measurement will be terminated early if a high peak was already detected. This means that a higher measurement rate can be achieved and long distances can be measured at the same time. However, the chance of false-positive distance measurements increases.
Normally the distance is calculated with a detection algorithm that uses peak value, signal strength and noise. You can however also define a fixed Threshold Value. Set this to a low value if you want to measure the distance to something that has very little reflection (e.g. glass) and set it to a high value if you want to measure the distance to something with a very high reflection (e.g. mirror). Set this to 0 to use the default algorithm. The other allowed values are 1-255.
Set the Measurement Frequency to force a fixed measurement rate. If set to 0, the Laser Range Finder Bricklet will use the optimal frequency according to the other configurations and the actual measured distance. Since the rate is not fixed in this case, the velocity measurement is not stable. For a stable velocity measurement you should set a fixed measurement frequency. The lower the frequency, the higher is the resolution of the calculated velocity. The allowed values are 10Hz-500Hz (and 0 to turn the fixed frequency off).
The default values for Acquisition Count, Enable Quick Termination, Threshold Value and Measurement Frequency are 128, false, 0 and 0.
BrickletLaserRangeFinderV2.
getConfiguration
()¶Return Object: |
|
---|
Returns the configuration as set by setConfiguration()
.
BrickletLaserRangeFinderV2.
setDistanceLEDConfig
(int config)¶Parameters: |
|
---|
Configures the distance LED to be either turned off, turned on, blink in heartbeat mode or show the distance (brighter = object is nearer).
The following constants are available for this function:
For config:
BrickletLaserRangeFinderV2.
getDistanceLEDConfig
()¶Returns: |
|
---|
Returns the LED configuration as set by setDistanceLEDConfig()
The following constants are available for this function:
For config:
BrickletLaserRangeFinderV2.
setMovingAverage
(int distanceAverageLength, int velocityAverageLength)¶Parameters: |
|
---|
Sets the length of a moving averaging for the distance and velocity.
Setting the length to 0 will turn the averaging completely off. With less averaging, there is more noise on the data.
BrickletLaserRangeFinderV2.
getMovingAverage
()¶Return Object: |
|
---|
Returns the length moving average as set by setMovingAverage()
.
BrickletLaserRangeFinderV2.
setOffsetCalibration
(int offset)¶Parameters: |
|
---|
The offset is added to the measured distance. It is saved in non-volatile memory, you only have to set it once.
The Bricklet comes with a per-sensor factory-calibrated offset value, you should not have to call this function.
If you want to re-calibrate the offset you first have to set it to 0. Calculate the offset by measuring the distance to a known distance and set it again.
BrickletLaserRangeFinderV2.
getOffsetCalibration
()¶Returns: |
|
---|
Returns the offset value as set by setOffsetCalibration()
.
BrickletLaserRangeFinderV2.
getSPITFPErrorCount
()¶Return Object: |
|
---|
Returns the error count for the communication between Brick and Bricklet.
The errors are divided into
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.
BrickletLaserRangeFinderV2.
setStatusLEDConfig
(int config)¶Parameters: |
|
---|
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:
For config:
BrickletLaserRangeFinderV2.
getStatusLEDConfig
()¶Returns: |
|
---|
Returns the configuration as set by setStatusLEDConfig()
The following constants are available for this function:
For config:
BrickletLaserRangeFinderV2.
getChipTemperature
()¶Returns: |
|
---|
Returns the temperature 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.
BrickletLaserRangeFinderV2.
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!
BrickletLaserRangeFinderV2.
getIdentity
()¶Return Object: |
|
---|
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). A Bricklet connected to an Isolator Bricklet is always at position 'z'.
The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.
BrickletLaserRangeFinderV2.
setDistanceCallbackConfiguration
(long period, boolean valueHasToChange, char option, int min, int max)¶Parameters: |
|
---|
The period is the period with which the DistanceListener
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.
It is furthermore possible to constrain the listener with thresholds.
The option-parameter together with min/max sets a threshold for the DistanceListener
listener.
The following options are possible:
Option | Description |
---|---|
'x' | Threshold is turned off |
'o' | Threshold is triggered when the value is outside the min and max values |
'i' | Threshold is triggered when the value is inside or equal to the min and max values |
'<' | Threshold is triggered when the value is smaller than the min value (max is ignored) |
'>' | Threshold is triggered when the value is greater than the min value (max is ignored) |
If the option is set to 'x' (threshold turned off) the listener is triggered with the fixed period.
The following constants are available for this function:
For option:
BrickletLaserRangeFinderV2.
getDistanceCallbackConfiguration
()¶Return Object: |
|
---|
Returns the listener configuration as set by setDistanceCallbackConfiguration()
.
The following constants are available for this function:
For option:
BrickletLaserRangeFinderV2.
setVelocityCallbackConfiguration
(long period, boolean valueHasToChange, char option, int min, int max)¶Parameters: |
|
---|
The period is the period with which the VelocityListener
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.
It is furthermore possible to constrain the listener with thresholds.
The option-parameter together with min/max sets a threshold for the VelocityListener
listener.
The following options are possible:
Option | Description |
---|---|
'x' | Threshold is turned off |
'o' | Threshold is triggered when the value is outside the min and max values |
'i' | Threshold is triggered when the value is inside or equal to the min and max values |
'<' | Threshold is triggered when the value is smaller than the min value (max is ignored) |
'>' | Threshold is triggered when the value is greater than the min value (max is ignored) |
If the option is set to 'x' (threshold turned off) the listener is triggered with the fixed period.
The following constants are available for this function:
For option:
BrickletLaserRangeFinderV2.
getVelocityCallbackConfiguration
()¶Return Object: |
|
---|
Returns the listener configuration as set by setVelocityCallbackConfiguration()
.
The following constants are available for this function:
For option:
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 BrickletLaserRangeFinderV2.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.
BrickletLaserRangeFinderV2.
DistanceListener
()¶This listener can be added with the addDistanceListener()
function.
An added listener can be removed with the removeDistanceListener()
function.
distance
(int distance)Parameters: |
|
---|
This listener is triggered periodically according to the configuration set by
setDistanceCallbackConfiguration()
.
The parameter is the same as getDistance()
.
BrickletLaserRangeFinderV2.
VelocityListener
()¶This listener can be added with the addVelocityListener()
function.
An added listener can be removed with the removeVelocityListener()
function.
velocity
(int velocity)Parameters: |
|
---|
This listener is triggered periodically according to the configuration set by
setVelocityCallbackConfiguration()
.
The parameter is the same as getVelocity()
.
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.
BrickletLaserRangeFinderV2.
getAPIVersion
()¶Return Object: |
|
---|
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.
BrickletLaserRangeFinderV2.
getResponseExpected
(byte functionId)¶Parameters: |
|
---|---|
Returns: |
|
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 sent and errors are silently ignored, because they cannot be detected.
The following constants are available for this function:
For functionId:
BrickletLaserRangeFinderV2.
setResponseExpected
(byte functionId, boolean responseExpected)¶Parameters: |
|
---|
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 sent and errors are silently ignored, because they cannot be detected.
The following constants are available for this function:
For functionId:
BrickletLaserRangeFinderV2.
setResponseExpectedAll
(boolean responseExpected)¶Parameters: |
|
---|
Changes the response expected flag for all setter and listener configuration functions of this device at once.
Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.
BrickletLaserRangeFinderV2.
setBootloaderMode
(int mode)¶Parameters: |
|
---|---|
Returns: |
|
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:
For mode:
For status:
BrickletLaserRangeFinderV2.
getBootloaderMode
()¶Returns: |
|
---|
Returns the current bootloader mode, see setBootloaderMode()
.
The following constants are available for this function:
For mode:
BrickletLaserRangeFinderV2.
setWriteFirmwarePointer
(long pointer)¶Parameters: |
|
---|
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.
BrickletLaserRangeFinderV2.
writeFirmware
(int[] data)¶Parameters: |
|
---|---|
Returns: |
|
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.
BrickletLaserRangeFinderV2.
writeUID
(long uid)¶Parameters: |
|
---|
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.
BrickletLaserRangeFinderV2.
readUID
()¶Returns: |
|
---|
Returns the current UID as an integer. Encode as Base58 to get the usual string version.
BrickletLaserRangeFinderV2.
DEVICE_IDENTIFIER
¶This constant is used to identify a Laser Range Finder Bricklet 2.0.
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.
BrickletLaserRangeFinderV2.
DEVICE_DISPLAY_NAME
¶This constant represents the human readable name of a Laser Range Finder Bricklet 2.0.