Complete NetworkTables API

Limelight OS features a NetworkTables 3 Client. It auto-connects to the NetworkTables 4 Server running on FRC Robots based on the Team Number / ID configured in the Settings UI.

Basic Targeting Data

Use the following code:

Java

NetworkTableInstance.getDefault().getTable("limelight").getEntry("<variablename>").getDouble(0);

LabView

C++

nt::NetworkTableInstance::GetDefault().GetTable("limelight")->GetNumber("<variablename>",0.0);

Python

NetworkTables.getTable("limelight").getNumber('<variablename>');

to retrieve this data:

key	type	description
tv	int	1 if valid target exists. 0 if no valid targets exist
tx	double	Horizontal Offset From Crosshair To Target (LL1: -27 degrees to 27 degrees / LL2: -29.8 to 29.8 degrees)
ty	double	Vertical Offset From Crosshair To Target (LL1: -20.5 degrees to 20.5 degrees / LL2: -24.85 to 24.85 degrees)
txnc	double	Horizontal Offset From Principal Pixel To Target
tync	double	Vertical Offset From Principal Pixel To Target
ta	double	Target Area (0% of image to 100% of image)
tl	double	The pipeline's latency contribution (ms). Add to "cl" to get total latency.
cl	double	Capture pipeline latency (ms). Time between the end of the exposure of the middle row of the sensor to the beginning of the tracking pipeline.
tshort	double	Sidelength of shortest side of the fitted bounding box (pixels)
tlong	double	Sidelength of longest side of the fitted bounding box (pixels)
thor	double	Horizontal sidelength of the rough bounding box (0 - 320 pixels)
tvert	double	Vertical sidelength of the rough bounding box (0 - 320 pixels)
getpipe	int	True active pipeline index of the camera (0 .. 9)
json	string	Full JSON dump of targeting results
tclass	string	Class name of primary neural detector result or neural classifier result
tc	doubleArray	Get the average HSV color underneath the crosshair region (3x3 pixel region) as a NumberArray
hb	double	heartbeat value. Increases once per frame, resets at 2 billion
hw	doubleArray	HW metrics [fps, cpu temp, ram usage, temp]

AprilTag and 3D Data

Use the following code:

Java

NetworkTableInstance.getDefault().getTable("limelight").getEntry("<variablename>").getDoubleArray(new double[6]);

C++

nt::NetworkTableInstance::GetDefault().GetTable("limelight")->GetNumberArray("<variablename>",std::vector<double>(6));

to retrieve this data:

key	type	description
botpose	doubleArray	Robot transform in field-space. Translation (X,Y,Z) in meters Rotation(Roll,Pitch,Yaw) in degrees, total latency (cl+tl), tag count, tag span, average tag distance from camera, average tag area (percentage of image)
botpose_wpiblue	doubleArray	Robot transform in field-space (blue driverstation WPILIB origin). Translation (X,Y,Z) in meters Rotation(Roll,Pitch,Yaw) in degrees, total latency (cl+tl), tag count, tag span, average tag distance from camera, average tag area (percentage of image)
botpose_wpired	doubleArray	Robot transform in field-space (red driverstation WPILIB origin). Translation (X,Y,Z) in meters, Rotation(Roll,Pitch,Yaw) in degrees, total latency (cl+tl), tag count, tag span, average tag distance from camera, average tag area (percentage of image)
botpose_orb	doubleArray	Robot transform in field-space (Megatag2). Translation (X,Y,Z) in meters Rotation(Roll,Pitch,Yaw) in degrees, total latency (cl+tl), tag count, tag span, average tag distance from camera, average tag area (percentage of image)
botpose_orb_wpiblue	doubleArray	Robot transform in field-space (Megatag2) (blue driverstation WPILIB origin). Translation (X,Y,Z) in meters Rotation(Roll,Pitch,Yaw) in degrees, total latency (cl+tl), tag count, tag span, average tag distance from camera, average tag area (percentage of image)
botpose_orb_wpired	doubleArray	Robot transform in field-space (Megatag2) (red driverstation WPILIB origin). Translation (X,Y,Z) in meters, Rotation(Roll,Pitch,Yaw) in degrees, total latency (cl+tl), tag count, tag span, average tag distance from camera, average tag area (percentage of image)
camerapose_targetspace	doubleArray	3D transform of the camera in the coordinate system of the primary in-view AprilTag (array (6)) [tx, ty, tz, pitch, yaw, roll] (meters, degrees)
targetpose_cameraspace	doubleArray	3D transform of the primary in-view AprilTag in the coordinate system of the Camera (array (6)) [tx, ty, tz, pitch, yaw, roll] (meters, degrees)
targetpose_robotspace	doubleArray	3D transform of the primary in-view AprilTag in the coordinate system of the Robot (array (6)) [tx, ty, tz, pitch, yaw, roll] (meters, degrees)
botpose_targetspace	doubleArray	3D transform of the robot in the coordinate system of the primary in-view AprilTag (array (6)) [tx, ty, tz, pitch, yaw, roll] (meters, degrees)
camerapose_robotspace	doubleArray	3D transform of the camera in the coordinate system of the robot (array (6))
tid	int	ID of the primary in-view AprilTag
priorityid	int (setter)	SET the required ID for tx/ty targeting. Ignore other targets. Does not affect localization

Camera Controls

Use the following code:

Java

NetworkTableInstance.getDefault().getTable("limelight").getEntry("<variablename>").setNumber(<value>);

LabView

C++

nt::NetworkTableInstance::GetDefault().GetTable("limelight")->PutNumber("<variablename>",<value>);

Python

NetworkTables.getTable("limelight").putNumber('<variablename>',<value>)

to set this data:

ledMode	Sets limelight's LED state
[0]	use the LED Mode set in the current pipeline
[1]	force off
[2]	force blink
[3]	force on

camMode	Sets limelight's operation mode
0	Vision processor
1	Driver Camera (Increases exposure, disables vision processing)

pipeline	Sets limelight's current pipeline
0 .. 9	Select pipeline 0..9

stream	Sets limelight's streaming mode
0	Standard - Side-by-side streams if a webcam is attached to Limelight
1	PiP Main - The secondary camera stream is placed in the lower-right corner of the primary camera stream
2	PiP Secondary - The primary camera stream is placed in the lower-right corner of the secondary camera stream

snapshot	Allows users to take snapshots during a match
0	Reset snapshot mode
1	Take exactly one snapshot

crop	(Array) Sets the crop rectangle. The pipeline must utilize the default crop rectangle in the web interface. The array must have exactly 4 entries.
[0]	X0 - Min or Max X value of crop rectangle (-1 to 1)
[1]	X1 - Min or Max X value of crop rectangle (-1 to 1)
[2]	Y0 - Min or Max Y value of crop rectangle (-1 to 1)
[3]	Y1 - Min or Max Y value of crop rectangle (-1 to 1)

| | |

camerapose_robotspace_set	(Array) Set the camera's pose in the coordinate system of the robot.
priorityid	SET the required ID for tx/ty targeting. Ignore other targets. Does not affect localization
robot_orientation_set	SET Robot Orientation and angular velocities in degrees and degrees per second[yaw,yawrate,pitch,pitchrate,roll,rollrate]
fiducial_id_filters_set	Override valid fiducial ids for localization (array)

Java

double[] cropValues = new double[4];
cropValues[0] = -1.0;
cropValues[1] = 1.0;
cropValues[2] = -1.0;
cropValues[3] = 1.0;
NetworkTableInstance.getDefault().getTable("limelight").getEntry("crop").setDoubleArray(cropValues);

C++

wip

Python

Python scripts allow for arbitrary inbound and outbound data.

llpython	NumberArray sent by python scripts. This is accessible from robot code.
llrobot	NumberArray sent by the robot. This is accessible from python scripts.

Raw Contours

Corners:

Enable "send contours" in the "Output" tab to stream corner coordinates:

tcornxy

Number array of corner coordinates [x0,y0,x1,y1......]

Raw Targets:

Limelight posts three raw contours to NetworkTables that are not influenced by your grouping mode. That is, they are filtered with your pipeline parameters, but never grouped. X and Y are returned in normalized screen space (-1 to 1) rather than degrees.

rawtargets

[txnc,tync,ta,txnc2,tync2,ta2....]

Raw Fiducials:

Get all valid (unfiltered) fiducials

rawfiducials

[id,txnc,tync,ta,distToCamera,distToRobot,ambiguity,id2.....]

Raw Crosshairs:

If you are using raw targeting data, you can still utilize your calibrated crosshairs:

cx0	Crosshair A X in normalized screen space
cy0	Crosshair A Y in normalized screen space
cx1	Crosshair B X in normalized screen space
cy1	Crosshair B Y in normalized screen space