13-04-2011 14:20

IKE

Re: paper: Legal Minibot Switch?

The attached link contains in my opinion an ideal minibot switch. Unfortunately I haven't been able to get approval to use it.

13-04-2011 14:52

jvriezen

Re: paper: Legal Minibot Switch?

If you haven't been able to get approval, its not the ideal switch


John Vriezen
Team 2530 "Inconceivable"
Mentor, Drive coach, Inspector

13-04-2011 16:26

Bob Steele

Re: paper: Legal Minibot Switch?

Would you like to see the "ideal" motors ??
I can show those to you too...
but they are , like your switch... illegal

Sometimes life has rules... and you have to follow them...
You don't have to agree with them... but you have to follow them...

If you ever get stopped for exceeding the speed limit...try and use the fact that in that instance your speed did not present any risk to anyone and that your automobile was perfectly safe at the speed you were driving. The policemen might very well agree with you...
and then give you a ticket...

Inspectors are kind of like that... I totally agree with your assessment that this would work a lot better than a legal switch...
BUT it is not a legal switch... hence you can't use it...

I am not a judge.... I am an inspector...
In court... judges can make this kind of determination...
policemen and inspectors only have the rules to abide by...
If you want to change the law... become a lawyer...
If you want to change how we live...become an engineer...

13-04-2011 17:00

Ninja_Bait

Re: paper: Legal Minibot Switch?

Our team is using one of those lamp switches that have a pushbutton that has an on position and an off position (ie, you push it once and it's on, push it again and it's off. I can't find the link right now.) I don't know how you're using the other switch, but this is great because it not only turns off the bot completely, it's very robust - it's an all-metal assembly, and it passed inspection at UTC.

13-04-2011 17:59

IKE

Re: paper: Legal Minibot Switch?

I actually posted the picture of that switch up on CD. It is a pretty good switch, but if you are running a really fast minibot beware that it could break after repated impacts.

You calling me a lawyer? Thems Fighting Words!

Please define "marketed as" for me.

The motor has a part number and a source. This is considered a source controlled component. The battery also has a part nubmer and a source, and thus is a sourced controlled component. "Switches" are defined as items "marketed or sold as limit switches or light switches" se update 12 or http://forums.usfirst.org/showthread.php?t=17169. As an engineer I have never come across as "marketed as" controlled drawing. I have seen functional specifications. I have seen source controls. I have seen part numbers. I have seen functional equivalence. I have never seen a "marketed as" specification before.

As a robot inspector, I did not receive training on what a "marketed as" component was. Its not in the manual, test, or Q&A. The Q&A did give us clues to what "marketed as" means. If the packaging has the right words, it is "marketed as"http://forums.usfirst.org/showthread.php?t=16722. If the KOP calls a micro-switch a limit-switch, then it is "marketed as". If a switch is sold in a store in the "light switches" section, it may or may not actually be a light switch (thank you Q&A). If I bought it on-line, then I am supposed to bring documentation. With said documentation, the Inspector has to judge whether or not my interpretation of "marketed as" meets their interpretation of "marketed as". There in lies the rub. The inspector is therefore no longer an officer, but a judge. As you have pointed out, this puts the inspector in the awkward position. This is usually just the LRI as the underling inspectors (I was one of those) defer judgement to the LRI (as they should).

My wife is a marketer. When she does a marketing campaign, she hands out fliers and posts signs. She makes sure the product is placed in a store in the section people would look for it. This is all within the realm of "marketing".

As a mentor, I read all the Q&A, I did not feel I was lawyering rules. When it said a light switch was the kind that mounted in boxes, we bought light switches that mounted in boxes. When it said that "light switch" was anything that was sold as a household light switch, I thought I was doing good buying a 3 amp 125V rated switches that can clearly be used to turn on a household light. When these were not allowed, we used limit switches. When the bot (which would make a 10 foot section of conduit jump out of its base on the practice field) did not trigger because "we can't prove it hit hard enough", we searched for a switch that had at least 5N of push force. We have now purchased approximately $100 of switches for the minibot. Many are too heavy to be competitive. Many do not have the required push force (even thoug they seem to work). Many are in a gray limbo of "hmmm not really comfortable calling those legal". because of this, we use the Tetrix switch and just keep buying more spares when they break. They are legal and light (though not too robust).

If you want to control which parts are legal, then do so (like the main robot motors). If you want to "open source" based on technical specs (like the new pneumatic rules), then do so. If you want to invent "marketed as" controlled components, then you need to define "marketed as", or be prepared for questions like mine.

The goal of a thread like this is to help change the "world" within FIRST of having silly rules like this where teams waste $100 buying wrong (or maybe wrong) switches.

13-04-2011 18:19

Bob Steele

Re: paper: Legal Minibot Switch?

This is a great comment...

I do differ to the LRI in these matters... but I am really just passing the buck...

I have felt all year that the minibot parts rules were not written in such a way that it is clear to any inspector ....

We all have our ideas on why rules are written.

Many years ago I worked for EPA and had to deal with the regulations that were written... if you think FIRST rules are convoluted you should see the Hazardous Waste rules... I actually was an inspector in those days and had to make these kinds of decisions...

I did, however, have the benefit of having another document that showed the intent of the rules... and often would refer to that...
We had the law, the regulations, and the intent documents...
and sometimes the hearings documents that gave the testimony and the resultant decisions....

Now I am NOT saying that we should EVER do that in FIRST...
If we did ... I would quit... :0)

I do find that nice tight regulations/rules are the easiest to interpret as an inspector....

The process you went through from wall switch to light switch is a great example of using technical information and making logical decisions. I especially liked that your definition of a light switch included the voltage and amperage ratings...

I, too, would hope that rules are written with specifics that are easily testable... the more you put these judgmental decisions in the hands of inspectors... the more variety we are going to see from regional to regional..

FIRST needs to remember that inspectors and referees bear the brunt of their words.... For inspection... tight rules that are very specific are always the best...

We also need to remember that many teams have never competed in this type of competition before... they will arrive with their own interpretations and then they will get upset when they find out that their interpretation doesn't fly....

The process is pretty difficult for a new team...

Education is the answer for rookie teams... we try to stress to new teams that they should talk to veteran teams about questionable issues when it comes to robot rules... it will save them in the end...
We also recommend straight questions in QA ... if you think you are treading the line... go and ask... USUALLY you will get an answer.

Thank you for being an inspector... and believe me, we are NOT Lawyers...thank goodness...!!!

14-04-2011 04:46

Tristan Lall

Re: paper: Legal Minibot Switch?

I'm right with you, Bob and Ike.

Ordinarily, the inspectors need to lean toward the most lenient ruling that still follows from a strict interpretation of the rules. (In other words, a conscientious team may have followed the rules in a way that was not intended. Ideally they should not be inconvenienced, as long as they are in strict compliance with the text of the requirement, and irrespective of FIRST's unstated intent.)

In exceptional circumstances, there can be deviations from this, but they are difficult to justify systematically, and end up driven by equity rather than by parity. (This crops up when FIRST or its quasi-representatives send mixed messages; the team was not in compliance with the rule, but was in compliance with what FIRST represented to them. Unfortunately, in this case, without the strict support of the rules, there are definite issues with unbalancing the competition to a small or large extent.) These are the most complicated special cases that require inspectors to not only know the rules, but also be familiar with FIRST's inner workings and the reactions of the community. What passes for equity at one event is not necessarily equitable across an entire season's worth of events—and this degree of inequity can't even be said to be predictable. The more we depend on this kind of ruling, the further we depart from consistency among events.

This minibot switch began as the former case—manageable, with a sufficiently lenient definition of "common household light switch"—and devolved into the latter with the Q&As and updates that offered several interpretations of the rule's meaning.

And while I realize that neither case is really what FIRST wanted—I presume they initially wanted a strict interpretation based on the GDC's intent—the rule was not written in a way that supports that method of enforcement. The credibility of the competition suffers even more when teams are asked to comply, not because of what the rules say, but because of what FIRST intended them to say.

As for intent statements, FIRST has managed to phase them into the rules in a couple places (in the form of blue boxes), but those are presently quite inconsistent in usage. A real intent statement needs to be something that aids in the interpretation of the meaning of the rule (e.g. specifies which meaning of a word to use), without adding any necessary elements of the rule itself—several rules and definitions in the 2011 manual fail on this account.

What we really need to see is strict and clear specifications for the things that are actually critical to the competition. Then, for everything else, impose as few restrictions as possible.*

*First stop: pneumatics. Although these rules were significantly improved with the permission to use a variety of actuators and reservoirs, there's really only one universal failure mode that must be avoided at all costs: explosive failure. As for game considerations, flow rate can be controlled with pressure and orifice specifications. Given pressure, we can set capacity (if air is intended to be scarce as a part of the game challenge) and actuator size (if force is a concern). Apart from that, do we really need any pneumatics rules? Does it matter that we're using Ø0.160 in ID pneumatic tubing instead of Ø2 mm ID tubing? If a device will fail non-catastrophically (not with a bang, but instead with the whimper of a rubber gasket being overcome), is it really FIRST's problem that the team didn't read the spec sheet?