Hi
We have been seeing that many teams use lamps in their robots to aim.
(not for vision processing, but just for the drivers to aim)
Could teams that have done that or have seen this recommend us what type of lighting to use? (Eg. LEDs, special lamp models or brands, etc)
Thanks in advance!!
We purchased a pack of these to put on our robot for Hartford, but never ended up getting them wired up correctly. They shine a nice rectangle of light when the slide is fully extended. Pretty sure that it’s the same aiming light that 230 is using, if you can find a video of them.
Your friendly neighborhood LRI chiming in here, while aiming lamps are legal, if in the opinion of the inspectors*, your lamp is too bright or aimed in such a way as to interfere or potentially interfere with the vision of the opposing alliance drivers or with their vision processing systems, you will be asked to modify it, lessen it’s intensity and/or the aiming point.
*If it hits me in the eyes and I see spots for even a few seconds, it’s too bright!
Some teams, like 2771 Code Red, use it to aim below the wall of the driver’s station so there isn’t a chance to hit the driver’s. We have potential to shine in the driver’s eyes since it’s mounted on our arm but the arm is only up while driving over defenses or shooting.
The same can be said for Vision tracking led rings, we custom made an led ring with 24 high brightness green 5mm LEDs. It ended up being quite bright( I am talking spots in the eyes for at least 30 seconds) so we have it powered off a spike, so we can momentarily turn it on for our vision tracking to work as we don’t want it to interfere with the other alliance.
We took a hacksaw to the end of one of these and powered it using a spike relay and one of those gray 12v to 5v converters that came in the kit of parts years ago. We only turn the flashlight on when we’re lining up for a shot and because we only shoot from the outer works, it’s aimed high enough such that it should never hit the opposing drive teams in the eyes.
If your flashlight CAN be aimed into the opposing alliance’s eyes, during match play it will do that, and your friendly inspectors will ask you to make changes. So wire the voltage converter to a spike, on a momentary button, so it shines only while actively aiming.
Green LED rings tend to be less bright, from experience the spots fade a lot sooner. But the same idea as above applies.
If you’re not sure if it is bright or not, look into it for a second and then decide. Caution you can hurt yourself!
Guys, I have it on good authority from an industry expert that white LED flashlights, greater that 100 lumens are a vision hazard. That is further complicated if your device has a lens to reduce the field of the emission. You do not need light output in excess of that level to be effective. Blue LEDs may have serious emission in the visible spectrum that may exceed safety standards depending on type. LRIs are very likely to be involved but so too will UL Safety advisors. IEC 62471:2006 Photobiological Safety of Lamps and Lamp Systems is the defining doc on this hazard. My recommendation is that you provide specifications on the output of your flashlight in W/m^2. If it blinds someone for even a short time, please consider that it is too bright. Even temporary blindness can cause people in the pits to trip over things they cannot see including the general public. You can use neutral density filters (available on line or from photo supply stores) to reduce the output. You can even use colored filters to reduce output and tune the source to the color your camera is looking for.
For inspectors, who I assume don’t know much about optics or the safety hazards involved, how do you recommend they go about verifying what is safe? Do you have a recommended W/m^2 standard? Since lumens are a measure of luminous flux, not luminous intensity which standard should be used? If there are safety measures in place such that it can’t be pointed at eye level during a match (for example, angled at the floor or is disabled in code at certain angles) is that sufficient? Is it feasible to just get an adjustable ND filter and dial it in until the inspector believes it is acceptable? How do I ensure I evaluate every team equally when inspecting? It’s great that you posted the IEC standard, but I’m not going to pay to purchase it in order to effectively inspect. After some web searches I found the classifications of RG1,2, and 3 from this spec. Obviously 3 is not allowed, but what’s the policy on RG2? Because I can have bulbs that are RG2 in my house, so to say they pose a safety hazard no matter what precautions are taken seems a bit of a stretch to me.
At Kennesaw teams were using the lights to target directly; no camera involved.
Mike, the standard we used (albeit subjective) was that if we were blinded by the flashlight while standing behind the drive teams, we spoke to the ‘offending’ team. Universally they were willing to come up with a reasonable solution.
Don, I understand the logic, but I don’t want a team to use the flashlight all through qualification and then have an opposing team in the QFs suddenly tell the Head ref or LRI that the light is blinding and now the team has no time to develop a remedy and must play their next match without the light. This hardly seems fair. Unless we have an established metric of where we draw the line I don’t see a way to avoid this situation.
Or we have inspectors standing behind the glass all weekend trying to get blinded and have them make the call. I don’t want to volunteer my eyes for this.
I think these were the flashlights. We had some not work, so order extra.
We attached 2 but only used one. We used a Spike and 12V to 5V power converter.
They were only on when aiming (button). You can see that here: Video
They helped us tremendously. We averaged at least 15 more points per match after adding the flashlights.
Mike,
There is no way to measure in the field. I checked the optical wattmeter prices and they were relatively expensive (>$1000). In general if the flashlight were sold as a self defense weapon, it is intended to temporarily blind some one. That alone triggers R9. I am sorry I can’t give you any better direction than this at this point. I recommend that your inspectors ask to see the light turned on during inspection while it is aimed at some non-reflecting surface and away from human vision to evaluate the output.
At the Sacramento Regional, the LRI expressed an additional concern: blinding audience members. If you have a field arrangement where the audience is behind either of the towers (as is typical when the venue is a basketball arena), this may be something to keep in mind, even if you only turn the light on when aiming.
Yes, it could potentially be a problem. The Inverse Square Law says that the light intensity will greatly decrease with distance, and the audience is usually a reasonable distance from the field. It’s funny how many things learnt in Physics class at school I am able to apply to FRC.
Alastair,
That is normally true for a non-focused light source. In the case of some flashlights, the reflector and or lens make a near columnar beam that does not follow the inverse square law. The first light I inspected using one of the defense flashlights had beam spot at about one hundred feet that was only 1’ wide. I could see faces in the balcony when it turned on.
As one of the teams who was called out for our flashlight this past weekend I think I can speak on this matter some. We have a flashlight with an aspherical lens that allows focusing the beam tight enough to see the LED die outline on the wall. We have been lazy and had it powered straight off of a power regulator so that it is always on. It is mounted on a stick that is approximately 5’ off the floor. Most of the time this wasn’t a problem, but if we bumped into the opposing alliances wall, it was positioned pretty perfectly to blind the drivers. We didn’t really think about this as we very rarely drive in that area. When it was brought to our attention we quickly added a spike and set it to be on momentarily so that we only turn it on while aiming from the outerworks when the beam is high up on the tower.
I think it is fair to ask teams to put it on a switch and keep it off except when aiming. The only excuse for not doing that is laziness. Trying to enforce rules about intensity is not the way to go.