I've been saying it since '98 and I'll say it again: inflatable cubes.

Matt

cubes, hmmmm
 

I do like the idea of changing the object this year. Unfortunately this my third year, so all I have know is the yellow and black balls. What kind of cubes were we thinking here? Because I don't usually see inflatable cubes when I go to the store, keeping in mind I don't look for them. Because from what I have seen, the balls were easily accessible things, unlike floppies. I still don't like the idea of footballs, but I guess as lopsided as the yellow balls were in 2000, they might as well have been footballs. I have also heard cones, I don't think road cones but cone shapes never the less. What do you guys think that the balls/cones/cubes will be put into or what not, I thought the 2000 goals were cool and I liked the mobility of the 2001 goals, what kind of crazy goals do you think they will make us deal with this year?

Re: cubes, hmmmm
 

I'll be honest and say I've never seen them. Doesn't mean they don't exist. ;) I thought cubes because they'd be harder to pick up but still be light like the balls are. And they wouldn't roll. Plus it'd just be cool. :)

Matt

I've said it before when this topic has come up, and I'll say it again. Ropes. Something involving ropes could be easy to set up, while still be something very very new for the FIRST community. Dean said, when asked about the game this year, "This one's so sick, even I'm proud of it." Whatever its going to be, its going to be good.

~Tom~, the guy who can't wait 'til January!:D

Water an Electricity...
 

Everyone seems to be concerned with water being a safety issue with our robots. We only have 12 volt batteries.

In an episode of Junkyard Wars, teams had to build machines to pull divers around under water. One team used an electric motor and a 12 volt car battery to power their machine. The team said that 12 volts really isn't dangerous when submerged under water. They proved this when everything worked and they won. (I think)

I don't understand the details but I do know that in most cases 12 Volts and water mix just fine. This is why you can touch both terminals on a battery and not be shocked.

Can someone more knowledgable on this shed some light on the subject?

I still don't think they will have water, but I think for reasons other than safety.

I'm not an electronics expert by any means, but, well, I think the problem with water and electricity has less to do with electrocution than it does shorting out the robot components.

Again, I've never tried it, but I don't think the robot controller and stuff and water would make good bedfellows.

Re: Water an Electricity...
 

I can't give the most detailed response but here goes anyway. Water is actually much more of a insulator than it is a conductor. The danger of water comes from the fact that it's a liquid and has a large surface area. Given that we use a relatively low voltage equipment (12V), the amperage over a distance of water is very low. To give an idea, I found information that stated there was approximately 2 Megaohms of resistance across a coffee cup of distilled water (only numbers on resistance of water I could find). Given Ohm's law (V=IR rearranged to I=V/R) we'd get .000006 amps or .006 milliamps. That shouldn't be a high enough current to trigger a damaging short.

I would, however, be much more concerned with the control system. Digital electronics are a bit more sensitive to short circuits than regular electronics are. They also aren't designed to handle the type of surges that can be caused by a short.

I hope I've gotten the physics right here. Someone please correct me if I'm wrong.

Matt

I think the biggest problem with water is not what it would do to the robots--the whole idea is to design one that handles the various challenges, and environmental variables are ones that FIRST has yet to deal with to my knowledge--but what it would do to competition logistics. It would not be easy to build a large playing field comprable to the sizes we've seen in recent years that would hold water, be economical, be quick to assemble and break down, and easy to transport. Plus it is time consuming to fill up a pool of that size, and a whole additional problem arrises when you consider that the water would have to be drained or pumped somewhere when they are finished. Even if FIRST were to come up with some idea to pull it off, I don't see how teams would be able to duplicate it. Besides, if you had a pool with water in it and the robots competed in it, water would get everywhere and then the robots would be wet when you pulled them out and would get the pits wet and the pits usually have a very rough electrical system...its just too much of a hassle.

Rather, I expect a more complex playing field with more moveable parts and things that need climbed. Also, I think time will play an integral role as everyone understands that and likes to watch competetors compete to beat a time limit.

What about a game in which there are alliances of two or three teams that compete to get the most objects, balls or whatever, in moveable goals, in the least amount of time, but where the objects are much harder to get to. Some could be under towers, others on them, and a few easy to reach. It would be beneficial for teams to be able to control and move their goals, so they could get their balls in them, but that would limit their mobility and agility. No team could do everything and there would even be room for defensive robots that get across the field and steal objects or guard goals. Scoring would be easy, as whoever has the most objects in their goals win, but the robots and game would still be very complex.

Just an idea, hope its intelligible as it is very late.

Eric

Water and electronics definitely DO NOT mix. Last year at the nationals we accidentally had a cup of water fall on the operator interface - instant disaster! The same thing would happen to the robot interface in a water-based event.
Do not be deceived by the resistivity figures for ultrapure water (18.2 meg-ohm cm at 25°C). Water which is exposed to the atmosphere rapidly becomes saturated with CO2, which forms carbonic acid, which is conductive. Also, anything the water comes in contact with - leftover soldering flux on the circuit boards, dirt, sweat from handling components - gets dissolved and adds to the conductivity of the water. Just think what kind of water quality you'd have after a few matches with robots running through it - and referees - and balls, pucks, or whatever.
Now, water would be fun challenge, but I think I'll wait until I work for the Navy for that. The chances of any robots still being mobile at the end of a day of water sports is, in my extremely humble opinion, zero.

Maybe......
 

Maybe they should have the fields outdoors and hope it rains like it did last year....Then we could have a water game......plus everyones robot was rain proof testest last year in the pits:D


http://www.chiefdelphi.com/forums/pi...rrow=4&trows=3

Water CAN be very Dangerous
 

Here is a little section on how small of current it requires for you to injure your body (Mostly in small mili-Amps, remember that your whole body works with electrcal impulses) One of the reasons we can touch low voltage batteries is the semi-high resistance of the skin, I think it takes about 50V to overcome that, but don't forget about cuts and abrasions that provide an easier path for the current. We would need to be even more careful in the pits where the 120V devices start to become involved.

Perception Current
One milliampere (1/1000 of an ampere) will be felt by most individuals as a slight tingling sensation. A defective hand drill or floor polisher might allow this amount of current to flow through a person standing on a dry wooden floor. Not bothered by it, he continues to use the equipment, until he happens to touch a water connection, heating register, metal window sash or other grounded metal object. He has now completed the circuit to ground and a much larger current will flow through his body.

Shock Level
If only five milliamperes (1/43 of the current required to operate a 25 watt lamp) flows through his body, it will result in a violent muscle reaction, throwing him away from the equipment.

Let-Go Current
If the current is much above 10 milliamperes, the person will lose his ability to release his grip on the electrical equipment. While the heart normally can continue to function, fatigue sets in, followed by death if no help is available.

Electrocution
At about 100 milliamperes (less than half that used by a 25 watt lamp) ventricular fibrillation occurs, the muscle fibers lose control and the heart is no longer able to pump blood.

Safety
The levels of current for perception, let-go and ventricular fibrillation vary widely from person to person. The above figures are based on the standard reactions of normal, healthy individuals. The effect of electrical shock on a child, elderly or sick person is much more severe. Even very small amounts of electric current can startle a person, causing him to spill hot liquid, fall from a ladder, or jump back into a greater hazard. For this reason, most manufacturers of electric tools, appliances and motors follow Underwriters Laboratories recommended maximum leakage current of 0.5 milliamps.

Hope this helps anyone unsure that water and electricity are not your two best friends

Water is possible!
 

Considering the battery is only 12 volts, I think it would be possible for a water competition, if they supplied a special water proof box for the control system, with all the wires coming in/out connected to fuses. This way at least a short would hopefully only blow the fuse. Then given the right materials to work with and sealed water pumps, you could seal your robot up pretty tight and use jet ski like water propulsion. It would be difficult and some shorts would be unavoidable, but I think the main problem would be not the robots but the logistics involved in building and maintaning a pool as a field. Can you imagine what would happen if it sprung a leak?

water?
 

I am not going to argue whether or not the battery could hold, but i don't really think that the battery would be the problem. The motors on the other hand don't like water. The logistics behind building a robot that is fully submersable and yet still can be worked on are too great. What happends when your robot breaks and you have to crack the seal to replace a speed controler, i just don't think it would be worth it. and also i am a human player and i don't really feel like rolling up my pants and dragging a 130 pound robot out of a puddle 4 times a day. thats all i have to say about water. I do think that obstacles would be cool though, just not water. what do you guys think should replace the balls this year?

The Real Problem
 

The real problem with a water field is "Where do you set up a practice field?" I'm sure that there are just loads of basketball coaches that would just love to have 6" or so of water on their nice hardwood gym floors.

I don't think it would be possible to set up a water filled practice field at any of the various places we have used for practice, and none of them is a gym.

Re: water?
 

I don't think many people would have a problem with this in florida, especially how late it is this year... its gonna be hot.