Magnets allowed?¿?
 

Is there any rule against using a powerful enough magnet to stick to the pull-up bar? We would be able to turn it on and off, obviously, so it doesn't go around attached to the other robots. :D

Thanks,
Team 992

Re: Magnets?
 

An electormagnet would not stay "on" or attached once the power was shut off. Your robot must be able to stay even when the power is shut off or you do not get the points for it.

On the other hand, you could use an electromagnet coupled with a passive latch to keep you held on the bar once power was shut off.

I looked in the manual and because electormagnets are not included in the KOP, they would fall under the Custom Circuits requirements (meaning they would not be allowed because of rule R52).

<R52> Custom Circuits may not:
• Directly affect any output devices on the robot, such as by providing power directly to a motor,
supplying a PWM signal to a speed controller or supplying a control signal to a relay module.

Please ask this question on the FIRST Q&A site and report back.

Note:there is nothing on the Q&A site so far that has the word magnet in it.

If anyone finds something to the contrary, please post it.

Re: Magnets?
 

thanx

Re: Magnets?
 

What about regular magnets that you can pick up in a store (for w/e you wanted to use it for)? Just wondering, since that wouldn't be an electromagnet.

Re: Magnets allowed?¿?
 

The word magnet only appears once in the robot section of the manual (5) and not at all on the Q&A site. That reference is talking about how the current sensor works.

According to the Parts Use Flowchart, if you can get it in one of the ok'd places then it's legal.

Re: Magnets allowed?¿?
 

Electromagnets are not allowed under the rules. If you follow the flow chart there is a section on electronics where it askes the question "Is the part a motor, solenoid, pump, or other actuator?" Since the answer is Yes you cannot use it. An electromagnet is by definition a solenoid, i.e. a coil of wire, wound around a form, that induces a manetic field by the introduction of electricity, to attract another metalic object. Sorry.

Re: Magnets allowed?¿?
 

part of the other trouble its the magnetic force could also possibly interfier with radio of other robots, or pull steel parts off if it was powerful enought to hold the robot... 100 posts! oh yeah!

Re: Magnets allowed?¿?
 

I don't know. It seems the spirit of that rule is an electromechanical device - an electromagnet is not that, right?, only half of that. And yes, you are certainly right, it is a solenoid by defn, but the spirit of that rule..... I mean, one could argue that any loop of wire is a solenoid, but we know the spirit of the rule. Would be rather interesting to see an electromagnet that could lift a robot when attached to a round bar and be able to spend some time on the bar with no battery power when the match is over. And to add to that, i wonder if magnet wire is allowed - i suppose so, but you have to keep to the correct size.... I highly doubt anyone could produce such a device given the rules, but gee, i'd be curious to see a prototype even if it isn't allowed :D

Re: Magnets allowed?¿?
 

Max,
An electromagnet would not produce interference with the radio modem in and of itself. Big coils do have this natsy habit of producing an arc at the switch when you try to remove current from the coil. That arc is capable of a lot of energy in the RF range and might be enough to disrupt the modem.
As to your closing signature, another form I heard "way back when" relates to the F104 fighter. Marines were heard to say it proved if it you put a big enough engine on it, you could get a brick to fly.

Re: Magnets?
 

It would be almost impossible to find a magnet that could hold 130 lbs. for a reaonable cost.

Of course, if you've got money to burn, it doesn't matter does it? :D

Re: Magnets?
 

You could buy 4 magnets that each hold 35 pounds though.

I seem to recall a surplus catalog showing 100pound+ magnets at reasonible prices (under 50 bucks) of course I couldn't tell you the name of the catalog , thats lost in the buzz of too many catalogs.

I hadn't thought of magnets. But they could be used to help 'find' the bar when you aretrying to hook it.

Re: Magnets?
 

Ohhh yes!!! I have a few. I have a pair of 1 1/4" neodymium disk magnets that have easily held me without a sweat.

Preferably you want NeFeB(aka neodymium or "rare earth") magnets with a second choice of SmCo. Ceramic and Alinco magnets are pretty much useless for this sort of thing.

All i can say is don't hurt yourself w/these things. Speaking from experience thye can cause some pretty bad injuries whrn they stick to stuff they're not suffosed to.
Suppliers:
http://www.wondermagnets.com/cgi-bin...manent_Magnets
http://www.allelectronics.com/cgi-bi...370&type=store

As far as isolating them from stuff that shouldn't be too much of a problem. Just put some thin steel sheet against all the unused surfaces and isolate that from the rest of the robot with some Aluminum or Plexi. I have never noticed a problem with RF interference either.

If you want an idea of the strength of neo magnets then bust open an old hardrive and it will contain some very small ones, which actuate the head assembly. (but not too old. If its a 3.5" then it will have them. any older and it may or may not.)

Instead of using them to attach to the bar, I see them as having greater applications moving goals. Simple: Powerful magnet + pnumatic detacher = easy goal dragger. This solves the problem of having nothing to grab onto. It also solves the problem or precisely aligning a mechanism w/ the goal.

Re: Magnets allowed?¿?
 

The problem with magnets is not that they can interfere with the radio modems, but that a changing magnetic field will create a current flow through wire I don't know how much current this would induce, but it could possibly be enough to mess with the pwm signals or other electronics of other robots. You may have to be careful to avoid this if you use a powerful magnet.

I found this website which has one magnet with 115 lbs. of holding force while weighing less than a pound for about $130. With a few of these, the hard part about hanging on the bar would be finding a way to release the robot at the end of the match.

Re: Magnets allowed?¿?
 

magnets change the way that electrons move so that could possibly interfere with the radio signals as previosuly mentioned. It could also interfere with the function of other robots assuming that the magnet was that powerful...some thoughts to consider...

Re: Magnets allowed?¿?
 

Even with VERY powerful magnets, it would be VERY difficult to induce enough voltage in anything to cause interference. It would take ALOT of gauss. and remember 1/x^2 rule. Anybody care to work out some Emag? Maxwell's equations Mmmmm...