Limelight 3 First Impressions?

Is the Limelight 3 worth the buy? More specifically, what features and benefits does it and the associated software have over our current setup with Limelight 2+ and PhotonVision?

Is Limelight MegaTag worth trying to use over the PoseEstimators and PhotonVision’s library?

Is the integration with Google Coral a good path to go down for object detection? (the ONLY problem with our autos is the consistency with picking up pieces, we had an easy 2.5-piece auto made in like 15 mins.)


We used Limelight 3 for retroreflective tape tracking and apriltags this year, had very good results with both. We used the limelight apriltags to feed pose estimator for autonomous and had a pretty successful 3 piece bump side auto on Hopper this year even with our small intakes.

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Has anyone found a good tutorial of how to use limelight April tags in your odometry

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Both of these are available with a Limelight 2+.

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We used the Limelight 2 or 2+ this year with the Coral and it worked great for cone detection

1323 does this for the second cone in auto

We ended up not using game piece tracking but in our testing we found color to be faster and reliable for gam piece tracking


I was talking to 133 during NE champs and they told me that they do their 3 piece auto with just game piece tracking. I don’t believe they even use a coral, just a simple limelight color filter, but I may be mistaken.

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You are correct, we used simple color tracking for game pieces on the floor and it worked really well.

Are you using 1 LL and switching pipelines? Or 2 separate LLs? If you are switching how easy is that? Any latency involved?

We have a separate lower-mounted limelight for tracking the retroflective tape so that we can calculate distance for our cone shooter. We do switch pipelines there depending on if we are aiming high or low. There is almost no noticable latency when switching pipelines including April tags in our testing, but we never measured it and nothing we are doing is that sensitive to pipeline switching.


Do you have a github code that i look into i have been trying to implement april tags with pose estimation for a long time, and can’t have any luck with that. Thankyou!

Our IRI branch should have everything there

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Aren’t you using limelight vision for your autonomous period?

We use limelight’s botpose(from the Apriltags) to correct our path planning in autonomous. Basically the robot uses the “pose estimator” to combine drivetrain odometry with Apriltags solutions to correct its location. We have PIDControllers for X and Y position that “push” the drivetrain back to the correct location based on those solutions.

So sorry to disturb you but when i try to move the robot in autonomous it moves directly in the straight direction with its maximimum speed even after it has been assigned specific path constraints . Is there any way i can contact you?

We had a similar issue to this last year. Make sure you are setting the PathConstraints in your PathPlanner.loadPath() method call AND that those are the values you are changing. I do not know the ins and outs of it but we tried just using the text boxes in the PathPlanner and were accidentally overwriting them in our code.

Here is the example from our code:

This question does not really relate to this thread. If you want to discuss this further in public I can make a new thread from here or you can DM me. Otherwise, this is a GREAT question for a new thread to begin with.