Illegal?

[benhulett]

Originally Posted by Kyle

I am not sure about the legality of those lights since they can be called as a distraction depending how bright they are, and if they can cause tracking problems with the camera, if we use it next year. Why would you want those lights on the bot if they can't be seen from the outside?
The lights do look cool though

-The electronics on our robot this year was horrible (wiring was everywhere, very hard to work on between matches, had several wires that came loose, etc), so another team electrician and I decided to make an "electronics box" based off a bot we saw at the competition. Their (not sure which team #) bot had a lid on the front with a 120mm fan on top, they just opened the lid and their electronics board was sitting there, neatly wired and everything. They had some type of matting surrounding everything too. Their problem was lack of light, they didn't put any lights in their box. Our idea is basically the same, just make a portable battery tray that slides in under our electronics box, and add lighting and a false floor for wiring. The lights will be there to illuminate the cable sleeving (UV reactive ), and will have white cathodes there if we can't see enough with the UV lights. So the lights will only be seen when we "open the hood".

Originally Posted by Cowmankoza

it is to my understanding that any light can be used on the robot as long as, 1. it is hooked up to a fuse and wiring in safely, and 2. not interefering with another robots vision system (i.e. no green)

-Will definitely be hooked up to a fuse, and hopefully my wiring skills will be good enough . Will not use green whatsoever.

Originally Posted by Simon Strauss

The heat shrink and neon wire cover are both FIRST legal and good ideas. The fan should be aswell. I dont see what you will use the acoustic pad for and the usage dictates its legality as a potential fire hazard if too close to electronics. Aslong as those lights dont interfere with CMU, any other type of sensor or driver visability they should be aswell if wired correctly.

when in doubt refer to the FRC flow Chart http://www.usfirst.org/uploadedFiles...ot,Rev%20G.pdf on page 19 and the inspection checklists


-Simon

-Thanks for reassuring me on that, I was pretty sure the heat shrink was fine, wasn't too sure about the wire cover. The acoustic padding was just a basic idea for the surrounding(we want it to be black, but I guess I could use plexi and just have a different sort of padding on the other side, eliminating the fire hazard.) It doesn't have to be acoustic padding, just wasn't sure where to look for that type of material.


-So far so good, thanks a bunch for the quick replies.

[IraJason]

Originally Posted by benhulett

-Will definitely be hooked up to a fuse, and hopefully my wiring skills will be good enough . Will not use green whatsoever.

Those cathodes shouldn't be that hard to wire in. I wound up putting connectors on mine and attaching them to a Spike. Just have it programmed to have that Spike turn on when you want it to and that should do it.

[Al Skierkiewicz]

OK guys, I do not believe that CCFL tubes on the robot pass the flow chart and would not have allowed them during the inspection process. Sorry, but should they break, the materials are hazardous and the power supply is 680 volts!
The super brite LED also would not pass as this device is likely to over drive the camera making it impossible to see other colors.
The lighted fan does pass inspection as long as it is 12 volts supplied from a 20 amp circuit breaker and does not pose a vision system threat. I have allowed them in the past. I believe that the ban on hard drives was based on the idea that this motor gave the team an advantage. I, however, would like to see this thought changed as a drive might make for an interesting application since single board computers obviously pass as custom circuit.

<R47> Additional electronic components for use on the ROBOT must be either COTS items, or assembled from COTS items.

Everyone uses tubing for a variety of purposes especially heatshrink. What it is used for may be disallowed during inspection so make sure your intended use fits the robot rule book.

[Billfred]

Originally Posted by Al Skierkiewicz

OK guys, I do not believe that CCFL tubes on the robot pass the flow chart and would not have allowed them during the inspection process. Sorry, but should they break, the materials are hazardous and the power supply is 680 volts!
The super brite LED also would not pass as this device is likely to over drive the camera making it impossible to see other colors.

I wasn't aware of the power supply voltage on the CCFLs--that would make me far more wary of allowing them. I would still wait on the implementation before banning the LED, though. An LED that may not pass inside this robot for letting out too much light may well pose no problem in this one.

[Daniel_LaFleur]

Originally Posted by Al Skierkiewicz

OK guys, I do not believe that CCFL tubes on the robot pass the flow chart and would not have allowed them during the inspection process. Sorry, but should they break, the materials are hazardous and the power supply is 680 volts!
The super brite LED also would not pass as this device is likely to over drive the camera making it impossible to see other colors.
The lighted fan does pass inspection as long as it is 12 volts supplied from a 20 amp circuit breaker and does not pose a vision system threat. I have allowed them in the past. I believe that the ban on hard drives was based on the idea that this motor gave the team an advantage. I, however, would like to see this thought changed as a drive might make for an interesting application since single board computers obviously pass as custom circuit.

<R47> Additional electronic components for use on the ROBOT must be either COTS items, or assembled from COTS items.

Everyone uses tubing for a variety of purposes especially heatshrink. What it is used for may be disallowed during inspection so make sure your intended use fits the robot rule book.

I have to disagree with you on a few points here:

1> While the ballast of the CCFL does boost the voltage to 680vdc, that is not against the rules, nor is it a safety hazard as long as the proper wiring / curcuit breakers are used.

2> Many items, on a robot, could be considered hazardous if broken. As long as the CCFL tube is intact, it is not hazardous materials. The key on this point is to ensure that it is well protected and that parts will not escape the robot (IE completely contained) should it break.

3> unless you place the 'super bright' LED directly in front of the camers, it will not have enough lumens to 'wash out' the CMU camera. If what you were saying was true then the 'stadium lights' would always wash out the cameras (instead of every once in a while) and cause them to never work because they are far brighter than a super bright LED.

JMHO.

[Brandon Holley]

didnt team 40 use LEDs, not cathodes

[Jessica Boucher]

Originally Posted by Brandon Holley

didnt team 40 use LEDs, not cathodes

Yes, we used red and white LEDs, covered with plastic shielding to dampen the brightness of the LEDs. They lit up when the robot was close to a tube.

[Elgin Clock]

Originally Posted by Jessica Boucher

Yes, we used red and white LEDs, covered with plastic shielding to dampen the brightness of the LEDs. They lit up when the robot was close to a tube.

I'm constantly impressed with how bright them suckers are even with a damper built over them. You need some shades to look at 40's bot most of the time. lol

Send me some specs and a link to where you picked them up Jess!!!
I want to brighten some things up as a side project...
AND... The Cavalier wants to be nice and bright for some CT summer night cruising.

[Brian Mocci]

195 used almost those exact fans on our 2006 bot. We had 2x 120mm fans with 4 blue LEDs cooling our transmissions CIMS. The fans passed inspection at a regional and at nationals.

[Al Skierkiewicz]

Daniel,
Besides the fact that the inverter puts out a very high voltage and requires better insulation on wiring than that provided in the kit, there could be any number of reasons to prevent it's use. The inverter should be considered a custom circuit and therefore can only feed the RC under the robot rules.

<R61> All outputs from the custom circuits must connect to the Robot Controller or to other custom circuits.

You might claim that is a non-functional decoration but decorations can only draw power from the 12 volt main battery, the inverter is the power source to the lamp, not the main battery.

<R110> Decorations may draw power from the 12v electrical system as long as they are powered via a dedicated 20A or 30A circuit breaker and do not affect the operation of other control system components.

You might even argue that custom circuits can and frequently do have local power supply regulators and/or negative power supply generators, but again the voltage is not higher than the main battery and those devices still follow the rules for custom circuits.

The lamps themselves are not roboust as anyone who built lights in 2006 can attest. I would venture to guess that several hundred lamps gave their lives to an errant ball during last year's game. Broken lamps produce dust and slivered glass. I wouldn't want to do a belly check on a robot and lay down in a pile of phosphor and glass out on the field.

Small, intense, light sources play havoc with CCD cameras especially those without an iris mounted in front of the pickup. The particular device linked in the first post is a "black light" or ultra violet output device. Although it has some visible light output, there is considerable radiation outside the visible spectrum. CCD pickups are capable of detecting a rather wide spectrum including IR and UV and this device would likely cause some interference.

Sorry, but I have to stand by my original response. Really cool but not for use on an FRC robot.

[dtengineering]

Hmm... well... good points (as usual), Al. I would have assumed that properly protected blue or red cold cathode tubes would be okay (assuming green is the only target), but you've got a point about the transformer pumping the voltage up. Although I would suggest that some reasonable level of LED lighting in a colour (or spectrum range) different from any vision targets should be okay, I would suggest teams make a point of clearing up any potential misunderstandings in the Q&A forum next year before decorating a robot with shiny flashy things.

I would suggest to anyone terribly disappointed by the concept of having cold cathode tubes potentially nixed at tech inspection that they consider lightsticks, such as cyalume http://www.cyalume.com/ They are plastic, chemoluminescent tubes... crack them and shake them at the start of the day and they should last for several hours of cool glowing robotness on the field, and in the pits... without draining batteries, or exposing anyone to high voltages, or the potential for cracked glass on the playing carpet.

Jason

[Daniel_LaFleur]

Originally Posted by Al Skierkiewicz

Daniel,
Besides the fact that the inverter puts out a very high voltage and requires better insulation on wiring than that provided in the kit, there could be any number of reasons to prevent it's use. The inverter should be considered a custom circuit and therefore can only feed the RC under the robot rules.

<R61> All outputs from the custom circuits must connect to the Robot Controller or to other custom circuits.

You might claim that is a non-functional decoration but decorations can only draw power from the 12 volt main battery, the inverter is the power source to the lamp, not the main battery.

Again, I'd disagree. The entire lamp (including it's cold cathode bulb) is a COTS item and that single COTS item is powered soley (sp?) from the 12v battery (through a breaker)

Originally Posted by Al Skierkiewicz

<R110> Decorations may draw power from the 12v electrical system as long as they are powered via a dedicated 20A or 30A circuit breaker and do not affect the operation of other control system components.

You might even argue that custom circuits can and frequently do have local power supply regulators and/or negative power supply generators, but again the voltage is not higher than the main battery and those devices still follow the rules for custom circuits.

Wattage is wattage. In order to up the voltage you must reduce the current (through a constant resistance). There is no rule against having higher than 12 volts on the robot (or lower, which by your definition would not be allowed either), just that the electrical supply must come from the 12 volt battery.

As long as it is breakered properly, then electrically it should pass inspection, according to the letter of the rules.

Originally Posted by Al Skierkiewicz

The lamps themselves are not roboust as anyone who built lights in 2006 can attest. I would venture to guess that several hundred lamps gave their lives to an errant ball during last year's game. Broken lamps produce dust and slivered glass. I wouldn't want to do a belly check on a robot and lay down in a pile of phosphor and glass out on the field.

And here we agree. Which is why I said that it would have to be contained within the robot completely if it did break.

Originally Posted by Al Skierkiewicz

Small, intense, light sources play havoc with CCD cameras especially those without an iris mounted in front of the pickup. The particular device linked in the first post is a "black light" or ultra violet output device. Although it has some visible light output, there is considerable radiation outside the visible spectrum. CCD pickups are capable of detecting a rather wide spectrum including IR and UV and this device would likely cause some interference.

Superbright LEDs put out ~2000mcd (give or take some due to manufacturer and wavelength). 2000mcd, unless put directly in front of the camera (less than 6") does not have enough power to saturate the CCD elements within the camera. In addition, the camera is searching for a particular wavelength, which happends to be very close to one of it's primaries (green). Thus as long as the LED has very little green in it's composite the camera will easily filter it out. In fact, at a distance of more than 6" it will be able to filter it out better than the stadium spotlights.

Originally Posted by Al Skierkiewicz

Sorry, but I have to stand by my original response. Really cool but not for use on an FRC robot.

For cold cathode lamps, I agree. There is too much engineering to make tham safe and not enough return (other than the 'cool' factor) for use on a FRC robot.

For LEDs I disagree. I can see plenty of feedback information that could be useful here. But I would caution those who would use them to be prepared to prove that your setup does not affect the CMU camera in any way, and to be prepared to disable the LEDs should you be required to do so.

[Al Skierkiewicz]

Originally Posted by Daniel_LaFleur

Wattage is wattage...

As long as it is breakered properly, then electrically it should pass inspection, according to the letter of the rules.

Superbright LEDs put out ~2000mcd (give or take some due to manufacturer and wavelength). 2000mcd, unless put directly in front of the camera (less than 6") does not have enough power to saturate the CCD elements within the camera. In addition, the camera is searching for a particular wavelength, which happends to be very close to one of it's primaries (green). Thus as long as the LED has very little green in it's composite the camera will easily filter it out. In fact, at a distance of more than 6" it will be able to filter it out better than the stadium spotlights.

Daniel,
I have to caution you, you are mixing apples and oranges here. Wattage is not the issue. 680 volts to exposed skin on students, volunteers and mentors is the issue as well as 680 volts to robot frame when the lamp breaks and the cathode touches the frame. I will grant you it is low current but I bet you wouldn't like it if you touched the exposed voltage. There is a difference between safe primary wiring practices and exposed high voltage.

On the camera, I am speaking from my everyday television experience. Small bright light sources are especially nasty to CCD pickups because the the AGC circuits and other electronics tricks used to get a nice looking picture are confused by bright spots in a normally lit frame of video. There are no optical filters before the pickup so all light reaches the face of the pickup where there are individual pixels for the three colors. Most light sources are fairly broad in their spectrum but LEDs can have some rather narrow bandwidths. A white super bright LED for instance has a rather high peak in the blue spectrum and a rather broad peak in the green. That being said, a small bright light produces a sharp image on the face of the pickup which for a variety of reasons, leaks light through the surface of the sensor and also reflects light on the back of the lens which then in turn sends it back to adjacent areas of the pick up. Besides the effect it has on the pickup, the circuitry used for making video outputs and the adjacent leakage paths, the signal then has a significant impact on white balance and local heating on the face of the sensor. All of these things aggravate the ability of the sensor to determine the presence of the correct color light. Add to that the 60 degree field of view of the lens and you are now producing problems that most teams will not be able to overcome.

[Cuog]

From someone who has been zapped by a transformer from these things I must say it hurts like a .... well it hurts a lot is what I'm trying to say. Its not likely a lethal amount but it certainly cause issues when trying to remove a robot or get to the power switch on the bot. With using UV lighting, there is certainly a problem with the CMUcams, when I brought the CMU can home to work with it I had issues with it getting distracted by my computer which is lit with UV CCFLs. This occured at a distance of roughly 3 feet. It is also important to note that the CMUcams are quite sensitive to a number of wavelengths and things such as too much red or blue can affect its ability to see green. There is an up and down to using a color in the "center" of visible light in that it is strongest and easiest tosee but it is also the easiest to interfere with.

[Adam Y.]

Originally Posted by Cuog

Its not likely a lethal amount but it certainly cause issues when trying to remove a robot or get to the power switch on the bot.

What is the power rating of the ballast? According to Wikipedia 100 watt ballast is capable of killing someone at that voltage. Even at one watt the ballast is still dangerous because Wikipedia states that you can't let go. Unfortunately, the values appear to vary wildly between website to website on how much current can kill.

In order to up the voltage you must reduce the current (through a constant resistance). There is no rule against having higher than 12 volts on the robot (or lower, which by your definition would not be allowed either), just that the electrical supply must come from the 12 volt battery.

This doesn't sound right. You don't necessarily need a resistor to boost the voltage to higher than the supply. In fact you might be confusing the fact that a florescent tube actually has negative resistance at a certain point and a resistor is needed to ensure that it doesn't just keep on trying to draw more and more current.