Limelight Cameras

Limelights are series of pre-packaged all-in-one vision systems that are used on many FRC robots for their simplicity coupled with raw performance. They were originally made by a mentor from FRC Team 987 (HIGHROLLER Robotics), and have spread to most FRC teams seeking vision solutions.

The list of Limelights one might encounter in today’s FRC would be the Limelight 2, Limelight 2+, Limelight 3, Limelight 3G, and Limelight 4. Limelight has made it quite easy to work with these cameras from flashing to playing with capture settings, the process is simple.

Getting Started¶

To get started working with Limelight Cameras or any Limelight product in general, you first have to download the: Limelight Hardware Manager.

Flashing OS¶

Flashing to OS of your Limelight has been made extremely simple.

1. Download the latest Limelight OS image

2. Open your Limelight Hardware Manager installation

3. Power off the camera

4. Hold the config button down while connecting a USB-C cable from your laptop to the camera.

5. Navigate to the tab labeled: Flash OS

6. Select the OS image you previously installed and wait for the extraction to complete

7. Click Select Device then Refresh Devices List

8. Select your target Limelight from the list

9. Click Flash Device and wait for it to complete

10. Once complete remove the USB cable

Network Configuration¶

Setting the Team Number¶

1. Power up your robot and connect your laptop to your robot’s network

2. Open the Limelight Hardware Manager, scan for Limelights, and double click the entry that appears

3. Alternatively, navigate to http://limelight.local:5801

4. Go to the “Settings” tab

5. Enter your team number and press “Update Team Number”

Setting a Unique Hostname¶

1. In the settings tab navigate down to the Hostname box

2. Enter a unique name for each camera

3. Click Change Hostname

Setting Static IP¶

1. Change IP Assignment to Static

2. Set IP address to 10.TE.AM.11

   • Team 254 uses 10.2.54.xx

   • Team 9106 uses 10.91.6.xx

   • Team 2056 uses 10.20.56.xx

   • Team 4915 uses 10.49.15.xx

3. Set Netmask to 255.255.255.0

4. Set Gateway to 10.TE.AM.1

5. Click Update

6. Power-cycle your robot

7. Access your config panel at 10.TE.AM.11:5801 and camera stream at 10.TE.AM.11:5800

8. If you are using multiple Limelights, give each Limelight a unique static IP address. Gateways and Netmasks should be the same across Limelights.

Web Interface¶

Accessing the Interface¶

After setting up your Limelight’s network config:

1. Power up your robot and connect your laptop to your robot’s network. Alternatively you can connect to the camera through USB if using a Limelight 3G or Limelight 4.

2. Use one of these methods to access the web interface:

   • Method 1: Open the Limelight Hardware Manager application, scan for Limelights, and double-click on your Limelight when it appears

   • Method 2: Open a web browser and navigate to http://limelight.local:5801

   • Method 3: Open a web browser and navigate to your Limelight’s static IP address with port 5801 (if configured)

   • Method 4 (USB): Connect via USB-C and navigate to:

     • Windows: http://172.28.0.1:5801

     • Linux/Mac: http://172.29.0.1:5801\

Accessible Features¶

Once connected, you’ll have access to:

• Settings tab: Configure team number, hostname, and other system settings

• Vision Pipeline tabs: Set up and tune your vision processing pipelines

• Camera & Crosshair tab: Adjust camera settings and crosshair parameters

• 3D Visualization tab: View real-time AprilTag detection and localization

All configuration is done through this web interface. Changes are saved automatically to your Limelight.

Other Configurations¶

Focusing the Lens¶

1. Power-on your robot.

2. Connect to the web interface as described in Accessing the Interface

3. Click the Ignore NT pipeline index to enable pipeline switching, and switch to pipeline 9

4. Set the pipeline type to focus

5. Go to the configuration tab, and increase stream quality to maximum 6.Make sure the camera is pointed at something with lots of features and contrast, such as an ARUCO board, a detailed scene, or a Siemen’s Star

6. Turn the lens to maximize the on-screen focus score

7. Once focused, apply 3-8 dots of super glue or super gel around the lens

Pipeline Setup¶

There are many different settings to tune to achieve optimal performance. As it would take a while to explain here is the documentation as explained by Limelight.

Hardware Setup¶

Mounting Limelight¶

Thru-Hole Mounting¶

• Use 1 1/4" #10-32 or #10-24 screws with nylock nuts

• Alternatively, use 38mm M4 bolts with nylock nuts

• Use plastic washers to preserve anodization

Threaded Mounting (Backside)**¶

• 2x M3 threaded mounting points

• Consider light application of Threadlocker

Wiring your Limelight¶

Power¶

Run two 18-20AWG wires from your Limelight to a slot on your PDP, PDH, or Mini PDP. It is recommended to use a 5A or 10A breaker.

Ethernet¶

Run an ethernet cable from your Limelight to your robot radio. Use twisted Cat6 cables with stranded wires (ideally 20AWG). If possible add a strain relief to your ethernet cable.

Troubleshooting¶

Status Bar Indicator¶

• Slow Cylon (Scanning): No targets detected by the current pipeline

• Fast Cylon (Scanning): Targets detected by the current pipeline

• Slow Alternating LED Blink: Hardware error (camera cable disconnected, sensor damage, etc.)

Reset IP address¶

• Hold the config button for 10 seconds after your Limelight has booted

• Networking configuration will reset to dynamic addressing on next boot

Flashing Limelight OS¶

Reference the section above all about Flashing OS.