2012 Team Update 4
 

It is online here.

It does not look like any major changes, but the alternate bridge thing might get tricky. The other clarifications are quite helpful.

Re: 2012 Team Update 4
 

Interesting - the rule allows for Wildstang style ramps, but doesn't allow you to put a partner on your back if you're not already touching the bridge. Useful to know.

I sure hope anyone ramping has made accomodations for us wide bots.

Re: 2012 Team Update 4
 

"Operation Bondé"
That I like...
If FIRST can pull it off smoothly, it sounds like an life saver.

Re: 2012 Team Update 4
 

Maybe this is a stupid question, but if the current bridge is inferior, why are we using it?

Re: 2012 Team Update 4
 

'cause.

Re: 2012 Team Update 4
 

This update is actually pretty important. The blue box at the end has really clarified the "stick something out the bottom of your robot to help balancing" as being perfectly legal. The Q&A responses this week made it look like it would be illegal.

Now, if you are on the bridge and you stick something down to the carpet it can be argued via the blue box clarification that your bumpers are perfectly legal as measured from the bridge that you are sitting on. Big clarification.

Re: 2012 Team Update 4
 

But if you are on the bridge and stick something down to the carpet, touching the carpet, wouldn't you not be balanced based off the rule that you must be fully supported by the bridge? Unless you mean putting something down that is not touching the carpet.

Re: 2012 Team Update 4
 

My guess would be they couldn't get it tested and have 2,500 of them donated / bought in time to ship the Kit Of Parts to teams, plus, if I'm not mistaken, DAP-1522 was new for the 2011 season, and switching radios each season could be a pain for teams.

Re: 2012 Team Update 4
 

one would retract it at the buzzer presumably.

Re: 2012 Team Update 4
 

I can only imagine cost is a large factor (street price is $99 vs. $65, plus you'd have to replace all the 1522s in the wild). I imagine FIRST sees this as an issue that won't rear its ugly head enough to justify the extra costs involved in outfitting every robot with the DIR-825.

Re: 2012 Team Update 4
 

but then the bridge would likely tip and no longer be within 5 degrees of horizontal.

Re: 2012 Team Update 4
 

I'm confused. Does this mean we can extend an appendage to assist in balancing the robot by having the appendage touch the floor, or that the appendage can only be used to help balance the bridge, and must be retracted once it assists in balancing?

Re: 2012 Team Update 4
 

This update means that it is legal to have stuff hang below the robot because the frame perimeter is not being violated.

What "thing" you make which takes advantage of this is up to you. It could range from zipties hanging in the corners of your chassis that make sure you are touching the key when your robot is mostly off it to sticking something down from the ramp to make it easier to balance (of course it can't end the match touching the ground.)

What a great lead in to Week 3!
Bryan

Re: 2012 Team Update 4
 

Reminds us of VEX season when we stick our robot almost off the blue/red tile, only to have a little zip tie touch it.;)

Re: 2012 Team Update 4
 

An arms race of wireless AP's? The venues' access points will inevitably get better with time (on average) and more powerful, meaning FIRST will always have to keep up with them to reduce interference. This way looks cheaper, but time will tell.

Maybe eventually they'll go to a radio-in-queue system, like VEX (still?) does.

Re: 2012 Team Update 4
 

I am now waiting for the "magical zip tie" to get ruled an illegal traction device...

On a more serious note can we actually get some ruling on rule G33 that actually explains what they really want?

Re: 2012 Team Update 4
 

The alternate "Bondé" radio is bigger, heavier, and has external antennas, compared to the more compact radio with internal antennas currently being used. I'm guessing the DIR-825 simply has better reception with the larger antennas than the compact DAP-1522.

I don't think anybody expected for a situation to arise where the current radio bugs out when there are over 60 APs in one place drowning out a single FIRST field AP. I'm imagining FIRST does test for some radio interference, but not extreme interference coming from over 60 WiFi APs at once.

I don't think there will be any major issues with the current radio, but it's good to see FIRST is thinking about these things.

The current radios will be set to only use Wireless N over the 5GHz band, which means there shouldn't be any interference from all the old APs on 2.4GHz.

The only way I can see this becoming an issue is if the venue recently upgraded their entire wifi network and installed tons of brand-new, high-end, 2.4/5Ghz dual-band, Wireless N APs relatively close together.

Re: 2012 Team Update 4
 

Remember 2005, Glenn? With those loading zones?

Re: 2012 Team Update 4
 

The Field Access Point has both 2.4Ghz and 5Ghz antennas (3 of each), so I imagine that before going to Operation Bondé, FIRST would try switching the frequency, in case the venue has a lot of 5 Ghz APs (I obviously don't know, but I think that Operation Bondé would be avoided if at all possible). Does anyone know about a regional last year that had an issue with too many APs that would cause FIRST to start sending better radios, or does it seem like they are preempting the problem?

Re: 2012 Team Update 4
 

Not really. All I remember is you guys won that year at CMP against Gila Monsters and Poofs.:ahh:

Re: 2012 Team Update 4
 

I just don't understand why we are using wifi at all. Sure switching to a bigger, more powerful controller is great (despite all the overhead of using an FPGA and not really taking advantage of it), but when all the wireless connections needed are known, specifically, FMS to 6 and only 6 robots, why do we need a protocol that is inherently built for arbitrary connectivity? Isn't this just asking for problems? And it gains us nothing. I think it would make a lot of sense to stick with a proprietary radio connection, and if you must use IP, establish a forward of the wired network run by the FMS over this radio link. I may be oversimplifying things, but the current situation is hardly simple.

So stick with the cRio and fancy shmancy Driver Station laptops, but stick with a wireless connection that works and is not so heavily dependent on a friendly environment.

Re: 2012 Team Update 4
 

Not necessarily, depends on when it's used and what other actions are performed.

Re: 2012 Team Update 4
 

I can't tell if this is a pointless rant or if you're being serious.



What wireless protocol and frequency would you use? 2.4Ghz? 5Ghz? Something other than wi-fi? There isn't much to switch to that isn't regulated.

Re: 2012 Team Update 4
 

The frequency is only part of the problem. Sure there is a lot of noise at 2.4 GHz because of the prevalence of Wifi, but I feel like most of the problem is the protocol. There are numerous hobby/RC bands just outside of 2.4 GHz that have no trouble maintaining a connection, even with several hundred controller/vehicle pairs in a smallish area, and I feel it's mostly because the nodes know exactly who are they are trying to talk to and don't have to deal with traffic from a gazillion other nodes (or if they do, because it's not fully scalable like IP, it doesn't have to look through and potentially forward every packet coming in, it can just ignore most of them). FIRST itself had a band for its own competition in 2008 and prior. In terms of regulations, for short range broadcasting I'm fairly certain there are a lot of bands where you don't need to tell anyone about what you're doing (I'm talking something like less than a few hundred meters). I'm sure there are some Ham radio buffs around here somewhere who know all about this.

Re: 2012 Team Update 4
 

I have a post from last year explaining the problem. The issue manifested at FLR and Florida, and matches couldn't be run until they were able to get the venues to shut down some of the APs.

Re: 2012 Team Update 4
 

Ah the memories (Actually more like AHHHHHHHH! THE MEMORIES! as they drag you off to the padded room in a straightjacket).

Re: 2012 Team Update 4
 

As stated above, this issue did occur in Florida last year. Considering that the regional is on UCF's campus, a campus with over 50,000 students, it's not a surprise that there was a lot of wifi in the area. Teams would spend over 5 minutes trying to connect to the field only to be told to try again next time because it was taking too long. Once a team did connect, however, their chances of being found the next time increased exponentially, at least that is what was explained to me. I believe that is why the problem only really occurred on Thursday, because by Friday everyone had been able to connect at least once. At our next regional the FTA wanted everyone to connect to the field at least once on Thursday whether or not they were inspected, probably for this reason.

Re: 2012 Team Update 4
 

I think you're misreading that. I think your configuration would be illegal because if the bot were placed flat on the bridge or carpet your bumpers would not be entirely in the zone.

Re: 2012 Team Update 4
 

But I think his point is that the robot is already flat on the bridge, the or only requiring one of them to make it legal. And of course what is "flat?"

Re: 2012 Team Update 4
 

Not that I know all of the details on the radio issue, but it sounds to me like they have identified a firmware issue with the model that they were using. It sounds like working with the radio providers, they have identified a model without the issue. Rather than replace all the radios for a rare complication, they have a plan to deal with a known issue if and when it occurs.

Again, I'm not an expert, but I assume that proprietary radio bands, especially ones with lots of bandwidth are susceptible to implementations issues in firmware and logistical surprises too.

There is nothing about the new system that precludes a special band or radio, but using off-the-shelf products, teams can pretty easily have their own N speed setups in their school or shop.

I'm also curious what you mean by FPGA overhead?

Greg McKaskle

Re: 2012 Team Update 4
 

I think you may be missing some of the physics. Your robot is not adhered to the bridge. Therefore you are lifting the weight off of one set of wheels and putting it all on the others. Yes, it changes the balance, but not necessarily enough to account for the distance raised. Think carefully...

Re: 2012 Team Update 4
 

If I have a 6 wheel drive robot and my CG is on one side or the other of the middle wheels, then I do not need the other set of wheels to remain flat on the bridge. If I stick something out between the wheels that are not needed (and hanging over the edge of the bridge) I will remain flat with respect to the bridge the entire time. Once balance, we retract. This update gives me the ammunition I need to fight for this mechanism.

What we really need is a clear and concise ruling on this bridge balancing device.

There is a reason many of us are asking the questions so specifically. The extra clarification in the latest update makes it clear to me that if my robot looks like it is not raising its bumper relative to the surface that it is on, then we are good.

The fact that so many of us are not in agreement means we may need further clarification.

Re: 2012 Team Update 4
 

me too, inquiring minds want to know !

Re: 2012 Team Update 4
 

They should just put big sheets of lead all around the field to stop all the arena wireless signals. :D

Re: 2012 Team Update 4
 

Don't need lead. A Faraday cage ought to work just as well, and those aren't lead.

Re: 2012 Team Update 4
 

Right-o. That's all I was saying; that this ruling isn't so much a ruling as an additional vaguery. I wouldn't count on the legality until something much more explicitly phrased comes along!

Re: 2012 Team Update 4
 

The point was that the lead would prevent everyone from seeing the field. Hence the :D

Re: 2012 Team Update 4
 

Hmm, I don't like the wireless bridge thing. To be blunt, I don't have a lot of faith in last minute swapping of parts by either officials or ourselves. Our team has had trouble with that in the past and it's been a real problem.

I think part of what it takes to do well in competitions like this is a matter of reducing risk and mitigating potential problems before they arise. For instance, last year the team counted on a potentiometer to determine position. They ended up destroying the pot (never heard how) and had to replace it. The new one wasn't of the same value and so they immediately burned up a motor by driving past the stop on the arm. The solution would have been some calibration system combined with limit switches. That would make it possible to swap parts and even if something went wrong and been working properly in minutes. We've learned this lesson so this year all parts with max/min extents have limit switches along with encoders and what not.

The problem is that something with configuration like the bridge isn't quite as amiable to swamping. A tiny setting off and nothing works and we are scrambling to track it down. We have the Axis camera, onboard computer, and cRIO all plugged into the bridge. There is a lot happening and it will have been extensively tested before the competition begins. Is there any way we could simply buy the newer bridge and use it in the competition so no swapping needed? The $100 cost isn't much compared to the piece of mind that having it already tested and working on the bot will bring.

-Mike

Re: 2012 Team Update 4
 

The update explicitly says this won't be allowed.

Re: 2012 Team Update 4
 

I too am a skeptic on how the whole bridge swap will work.

-How will teams mount it in a few minutes? We usually velcro our radio to our robot, then zip tie around it so it has no way of falling off. We also zip tie all of the wires to the radio in such a way that they can't come out, and add duct tape to the wire connections since some of them are friction fit (which is really really bad, in our experience).

-The backup radio is significantly larger (~3" in one dimension) than the old one. I expect that it simply won't fit on some robots designed for the existing radio.

-Since the backup radio runs on 12v instead of 5v, they are giving us a 4.5' power cable to plug into our PD board? The update seems to indicate that the power cable goes with a bridge (and that each team will get a power cable in the queue line). I don't see how they expect teams to integrate it into their wire harness (zip tie it in) if the radio is decently far away from the PD board, in a few minutes. I don't see how they expect teams to assume reliable radio power (which is very critical) if they can't secure the wire from damage.

-All of this is done before every match (as many as 12 quals + up to 9 elim matches)?

Re: 2012 Team Update 4
 

I echo all of these concerns. Hopefully we'll never find out how it would work.

Re: 2012 Team Update 4
 

Rather than hope it never comes up, I think they should just let us use either if we are concerned about it. I know I'm going to have the team order one on Monday night just so we can make sure it will mount right in with our existing system. We were planning on tucking it in pretty tight and the larger one will simply not fit unless we do some work. The current plan was the mount everything low and tight to a removable base. We were even making custom cords to keep run lengths short and controlled between some of the components. This is the type of change that I foresee causing us lots of problems on competition day if we don't plan for it now.

-Mike

Re: 2012 Team Update 4
 

Having lived through FLR last year, I'll take any solution to the problem and be grateful for it.

Re: 2012 Team Update 4
 

Does anyone know how the replacement wireless radio will be furnished for mounting? I wish they would tell us it will have Velcro, and which side of Velcro it will have.