Reflective Tape on Robot

Is it illegal to put reflective tape on robots? I couldn’t find any rules against putting reflective tape on a robot in the game manual and was wondering if I was just blatantly missing something here?

The main restriction is R8 ( c ).

Any devices or decorations specifically intended to jam or interfere with the remote sensing capabilities of another ROBOT, including vision systems, acoustic range finders, sonars, infrared proximity detectors, etc. (e.g. including imagery on your ROBOT that, to a reasonably astute observer, mimics the retro-reflective features of vision targets described in Vision Targets)


Generally, anything reasonably emulating a vision target would not be allowed.

Personal advice: steer clear of it. You’ve got more important things to do than argue with an inspector over it.


Some talk from our team:
“Imagine if we could use the 45” to block shots? Just play defense and the shots won’t go in!"
“So we can have 12” on both sides of the robot as sticking out. What if we extended out a banner like thing that had the exact geometry of the retro tape on the Hexagon? Instead of
tracking the Power port, they will be shooting at us!"

Needless to say, this was not carried out.

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Actually, as near as I can tell, that statement is perfectly legal. Might not be overly effective, given the abilities of most shooters, but legal all the same. Just using the mass of you robot to block shots (i.e., deflect the PCs from their target path) isn’t a violation of R8.

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I am more referring to G17

Although it wasn’t reflective tape, Team 3871 put a polycarbonate shield on the side of their robot to try and block shots from low shooter with the added benefit of reflecting back the limelight. You can see it in Q66 when they play defense against 3130. We talked to 3130 later and they confirmed that their limelight did get confused from the polycarb shield. We also put a corrugated plastic shield on the side of 2450 for our elimination matches and although it had a chance of blocking balls, I don’t think it effectively reflected limelights in the same way as polycarbonate.

In conclusion, although having polycarbonate reflected limelights and cost 3130 at least 3 balls, the actual blocking aspect of it didn’t do anything and it was just how it passed inspection. The corrugated plastic didn’t do anything though.

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Keep in mind that the clarification in R8 (blue box item a) that you are not allowed to obstruct or limit the vision of drivers or coaches. Blue box item c prohibits items “specifically intended to jam or interfere with the remote sensing capabilities of another robot, including vision systems”.

Jamming and interfering are different activities than obstructing or limiting, and the jamming and limiting must be a “specifically intended” result of the object in question. So the defensive team in this case was welcome to use an opaque panel, that would have completely obstructed the view of the vision system, because they would not be jamming or interfering with it… the vision system would still have a perfect view of the opaque panel and would not confuse it for a vision target… but the opaque panel could not be used to obstruct or limit the human view of the field.

But the bottom line is that this is an offensive game and the height limits ensure that the “block the camera / block the shot” strategy is likely to be a very difficult path to victory.


on this topic, I have noticed that quite a few teams have had their limelights turned on while playing defense. whether this has been effecting other teams shots/vision or not I am unsure, but I hope that refs start at least telling teams to turn off the lights on while playing defense.

As a part of 2450 and from watching the matches and talking to 1619 after I can confirm that the shield actually did do a large amount of work for the matches because they caused both them and Patriotics 5913 to miss a large amount of shots in the elims

I will agree that it gave us some troubles at first but due to the height restrictions, the blocking is efficient only if a team has a static shooter. A variable shooter that uses vision tracking and a turret were quite effective in allowing us to shoot from a farther distance where we could see over the blockade and sink some balls.

I actively wondered if this was happening to 5413’s robot as I watched the webcast of the Miami Valley playoffs. A defender had some bright LED lights blasting and Stellar’s turret appeared to be rather confuzzled.

What is the inspector thought on minimal use of retroreflective tape inside conveyor cage areas for use with retroreflective light sensors for power cell detection? These taped areas point inward typically, not outward, and would likely be blocked by robot superstructure.

I believe the defender you’re referring to was 3324 in QF1-1. As far as we could tell, their LED light was not the cause of the interference. Their robot was tall and was able to obstruct our camera’s view. I assume the aluminum frame of their robot was reflective enough to cause a green “blob” to show up in the camera which the turret happily tracked.

We’re using Chameleon Vision running on a RPi 4. We’re not using any of the functions that sort/eliminate blobs by their infill percentage or aspect ratio, which would probably eliminate that problem. That was a case of “the people loading the trailer need to pack the robot so they can get home before midnight”… So we didn’t have as much time to dial in the camera as much as we wanted.

Can’t speak with an inspector’s view, I’ve never played that role. However, even a conservative reading of the rules would allow internal use of retro tape with sensors for a mechanism. The rule is worded in a way so that the only thing you are explicitly not allowed to do is to mimic the actual vision targets on the field in order to confuse other robots.

In theory, you could even have your own unique vision targets on your robot to allow some kind of cooperation in auto with alliance partners, but that would require a very fine parsing of the rules and probably isn’t worth it.

In PCH Gainesville Final 1, you can see 6829 (red) block a few of 1746’s shots with a polycarb blocker they added on for elims. Blocked shot happened at the blue trench, around 0:38 -

This defensive strategy is a dangerous game though! 6829 may have blocked a few shots and prevented a few more from going in, but they also got called for G10 twice in this match. Those 30 pts in penalties outweigh the ~10-15 pts prevented.

From an RI’s perspective. If it obvious it is intend to mimic a target, we will discuss it. If it is a functional part of the robot and does not obviously mimic a target, it will probably pass will little discussion. If a referee feels it interfering with other robots sensors (not just blocking) or if a team complains to a referee it will get passed back to the inspectors to evaluate. That will happen with varying degrees of emphasis by the Head Referee.