Re: Team Fusion #364, Bayou Regional, FMS Woes
 

I wasn't intending to pick on you Andrew; your post actually included good information related to the construction of the hardware. But it still highlights the issue that "there shouldn't be a problem with signal strength", yet as Eric said, multiple teams were reporting a "dead spot" on the field and mchristina said the same thing about a different regional, so the data says there is some kind of real problem that smells an awful lot like signal strength in some part of the field.

Re: Team Fusion #364, Bayou Regional, FMS Woes
 

After mchristina444's post, it reminded me of what George had told me. So I just wanted to throw it out there so others more knowledgeable could add credence or call shenanigans. So thanks to apalrd for that :) Yet, let me ask a different way: Is it possible for there to be wave cancellations in the near field? ...some odd RF effect? Just curious.


I'm with Gary, though. We're not here to pick on anyone, but there is a body of evidence collecting here. I know people like Greg M. are following up and I am grateful for that. Let's see where the data leads.

Eric

Re: Team Fusion #364, Bayou Regional, FMS Woes
 

There's a body of anecdotal randomness...
Engineers measure things...

Re: Team Fusion #364, Bayou Regional, FMS Woes
 

Also, after talking to multiple teams at the Bayou Regional, there was more than just my loss of signal by the scores table. Sadly I don't remember specific team numbers. Talking to the FMS representative, I repeatedly used the word "dead zone" because that was my first thought on the field. He shot down the idea immediately. Having the issue in that one area of the spot. He said "Coincidences happen more often than you think".

But one thing did confuse me, why was this only happening to ~5 teams if it was a dead zone in the wifi? Router placement on the robot? etc?

I'm not going to flat out blame this on the FMS but I do believe it is something to look into.
Having this happen more than 3 times in different matches can really bring down your rankings. I experienced that first hand.

2078 Driver

Re: Team Fusion #364, Bayou Regional, FMS Woes
 

The biggest idea I have is some sort of interference on the FMS or the 10.3.yy IP or something of that sort. The biggest evidence is the occurance of our problems only when there was a large crowd or devices. What else could the packet loss come from, since it only happens when there's a crowd?

Re: Team Fusion #364, Bayou Regional, FMS Woes
 

I've asked my team to pull our logs. We didn't have any comm issues during the Friday/Saturday at Bayou. The only problem we had in a quali match was traced back to controller issues in our second match.

Hopefully this helps.

Re: Team Fusion #364, Bayou Regional, FMS Woes
 

I'll pull logs from our DS. We had control issues in two early matches due to a bad CAN network, and at the start of one match I saw our robot connect, run fine for a few seconds, lose comms, reconnect, lose comms and finally reconnect for good. There was one match in elims where we took FOREVER to connect and couldn't align our robot. Much longer than any other bot on the field. This despite the fact the we power up our robot shortly after the previous match ends. We had good comms during all of our matches as far as I know, however, despite simultaneous camera feeds going on the eeePC we use for a DS.

Re: Team Fusion #364, Bayou Regional, FMS Woes
 

So true - I hate what happened to the teams in this thread but there is no evidence (yet). Let's say the FMS said "OK, this is our fault". What direct action (not redesign the system) could they take to fix it? We can't tell them what to fix!

Re: Team Fusion #364, Bayou Regional, FMS Woes
 

Opportunity had our routers freak out and die. the one in the kit had the issue and it later litterally fried, then we got a new one and after a while of practicing and by the time we got to competition it started doing it so bad it was every match. it worked in the pit but not well on the feild. when we went to the officials spare parts station and got one lended to us, it worked perfectly, a couple other teams had issues with them too, i think it happened to the last few to hook up connections, or it was that a while after use the parts glitched up badly. Our advice is to bring a brand new one to competitions, and maybe a spare if affordable. i did notice that some of the last few teams to hook up wireless connection had issues staying online and connected on the feild. same with the practice feild

Re: Team Fusion #364, Bayou Regional, FMS Woes
 

That wasnt our problem...

Re: Team Fusion #364, Bayou Regional, FMS Woes
 

Our router all connections and everything to do with the control system of the robot was replaced atleast twice the issue was never resolved we checked all code and various settings finally we went to data collecting because we had no support or solution from fta that we hadn't done The robot ran wirelessly on the practice field but did not connect reliably to the field

Re: Team Fusion #364, Bayou Regional, FMS Woes
 

By the support of the FIRST community, Gracious Professionalism of FIRST, and the gracious support of Lucien Junken from Robonauts, Team 118, Team Fusion 364 is officially going to the Lone Star Regional!

Some things to mention at this point. When we get to the competition on Thursday, we will be going out to the field early along with some other problematic teams, and test communications. We're not going to change anything with our configuration, including software or hardware. We want to isolate the problem first, then go about some troubleshooting.

At this point, we are leaning towards RF interference. Our router was set to channel 1, but I'm not sure the channel configuration of other robots.

I know channels 1, 6, and 11 are most often used because their RF frequencies do not overlap.

Even though not all teams have problems, FIRST does have a problem.

Take for example this video from the iPhone 4 unveiling a few years ago:
http://www.youtube.com/watch?v=znxQOPFg2mo

The audience was way smaller. The iPhone 4 could not connect at all. To fix this problem, Steve Jobs had to ask the audience to shut off all electronic devices.

FIRST needs to do the same, or use a different technology. Simply using the 5GHz band of Wireless N would help tremendously.

This doesn't answer the question of why just us, but this is a problem at the competition.

For now, FIRST should ask the audience to place their cell phones into airline mode. Students on the field need to just leave their phone in the pit with them.

Re: Team Fusion #364, Bayou Regional, FMS Woes
 

I'm not sure how the crowd's devices would have affected it (I'm not saying they didn't), but I don't think they could have caused an IP conflict. The 10.0.0.0/8 subnet is fairly uncommon for your average user, and they would need to somehow be on the network (the chance of their phone randomly being connected to your SSID with its encryption key are next to none). The only way that there could have been an IP conflict is malicious intent (and I'll talk about the issues with this momentarily). I don't know a lot (nothing really) about RF, but, I suppose that a lot of phones trying to scan might cause interference, but I would think it would be on the 2.4GHz spectrum (which I think the field doesn't even use here in the states, iirc, the 2.4GHz antennas are disabled, but must be inserted anyway). In terms of localized cancellation, I believe the field AP is rated for 16 networks, and is only broadcasting 7, so I don't think that should be a problem.

About malicious intent, the field uses WPA, as does the practice field, WEP is a broken encryption scheme, and is not used by FIRST. The actual field also probably does not have WPS (it isn't a home router after all). Someone talked about just programming a bridge as another team, it would work, but I feel like the problem would be a little less consistent (IP conflicts are strange beasts). That said, MITM is not out of the range of skills of FIRST students, after all, we all know how to use google, but setting up a MITM attack that would survive lots of network disconnects and reconnects would be fairly complicated (ettercap might be able to do it maybe, but I doubt it would work without significant professional training).

I tend to agree that "It should work, therefore it does" however I am aware that the field doesn't always work, and I really hope that you find the source of your issue, I for one will be watching this to see what the result is.

Good Luck,
Oliver

Re: Team Fusion #364, Bayou Regional, FMS Woes
 

I think you are thinking off the Custom Control Interface from eStopRobotics. I haven't gotten a chance to use it, so I can't say if it works well or not.

I've had bad experiences with the cypress board in the past and instead we choose to have a student write a custom program for the teensy board. One of our programmers wrote the code to make it emulate a joystick. I don't have it to post yet but we should soon. He said it was only about 20 lines of code and most of the work was already done by other teensy developers. We haven't run this through a competition yet, we go to Dallas next week.

Re: Team Fusion #364, Bayou Regional, FMS Woes
 

They do. I have also seen an AirTight sensor on the scoring table, I was curious what it was so I did some googling: http://www.airtightnetworks.com/home...-security.html

It sounds like you were trying to pull a channel setting off of the radio. he client does not choose the channel in a WiFi setup, the AP does meaning that either all teams or every team in a single station would likely use the same channel. Given Andrew's comment of only 3 antennas per frequency it is likely that all 6 SSIDs are broadcast on the same channel meaning all teams are using the same channel.