WiFi at a week zero event

We are hosting a week zero event, and are wondering how much effect having our schools WiFi networks on during the competition would have. The gym where we are setting up the field has at least 3 access points, each broadcasting the same 3 ssids in both 2.4 and 5ghz. Thanks for any input you can give, as it will help us when discussing this with the school district network administrator.

We have seen issues with Wi-Fi at other off-season events. While those three access points may not cause much of an issue, having two dozen robots in the room using Wi-Fi can! As a best practice, you should try to eliminate as many sources of interference as possible, since the teams will bring plenty of their own.

Edit: I’ll also be there at your event to help look over robots. I love having a couple of options for Sunday week 0 events in addition to all of the Saturday ones!

Do the school APs use or serve DHCP addresses in the 10. range?
That might cause a conflict if you aren’t careful to avoid connecting to them, or if the APs have the same 10. address as one of your teams.

Otherwise, I think leaving those three school AP’s on will work okay for week 0 play. How many teams are you thinking?

You will have to keep an eye on the active network which you can do with a tool like InSSIDer. You may need to shift channels on whatever field AP you may be using.

Will you be using FMS Lite with a central field AP?

The school does use IP addresses in the 10. range. We are using a central ap for the field, and are planning to run Cheesy Arena for the software.

You’ll need to keep an eye on bandwidth utilization by the teams.
The particular problem is heavy camera use (multiple, high-res, low compression) will impact that kind of environment.

Do you have some test robots (or just radios & roboRIO/cRIO) you can check running simultaneously in the gym connecting through your field AP?

The 5GHz wifi shouldn’t affect the competition because the D-Link AP’s use 2.4 during competition. The 2.4G wifi ap’s in your gymnasium may possibly interfere with the FMS during competition.

Also doesn’t this year’s FMS use mDNS so that the roboRIO connects via roborio-####.local and only uses a static IP as a fallback? The routers are configured to assign the RoboRIO a DHCP address (at home use) which I believe can vary should you be using other ethernet devices, such as Axis cameras.

I know thats how we configure them for home use but the competition bridge config may change to set Static IPs. Hopefully FIRST releases some information & if they did we should take a look at the way the FMS connects to the robots.

What channel(s) is(are) the school using?

Channels 1, 6, and 11 are non-overlapping. If you can stay away from the School’s channels, you should be ok. If you are on the same channel as the school, then you could overload the network. Everyone using the School’s wifi could interfere with using the field wifi.

We’ve found interference with teams numbered 15XX at our offseason event. We had to disable the school wifi.

I can’t think of any team who has numbers in that range… :rolleyes:"

Here is a scan of the networks and channels from in the gym. We have last year’s robot and this years robot that we may be able to test.

It’s more fundamental than IP addresses.

You don’t want to be competing with other wifi access points for the same radio channels. Otherwise you’ll have difficulty providing 7mbps to each driver station <–> robot pair.

For real competitions this year the RoboRIO and Drivers Stations will still be using mDNS and getting IPs via DHCP.

Since week zero events will be using last year’s FMS (or a third party FMS such as Cheesy Arena), you will need to go into the RoboRIO’s settings and set it to a static IP of 10.xx.yy.2, and make sure the radio isn’t trying to serve out IPs via DHCP.

Similarly, you’ll want to make sure everyone has their driver station configured for the correct IP (10.xx.yy.5).

That looks pretty ugly to me… I would definitely see if you could get some of those access points in and near the gym turned off for the day.

So we all know that creating hotspots is not allowed as well as walkie talkies. However, is there any rule against CPC radios?

5.5.8 Special Equipment Rules
T21 The only equipment, provided it does not jam or interfere with the remote sensing capabilities of another Team, including vision
systems, acoustic range finders, sonars, infrared proximity detectors, etc. (e.g. including imagery that, to a reasonably astute
observer, mimics the Vision Guides), that may be brought in to the ALLIANCE STATION are as follows:
B. non-powered signaling devices,
C. reasonable decorative items,
D. special clothing and/or equipment required due to a disability
E. devices used solely for the purpose of planning or tracking strategy provided they meet all of the following conditions:

  1. do not connect or attach to the OPERATOR CONSOLE
  2. do not connect or attach to the FIELD or ARENA
  3. do not connect or attach to another ALLIANCE member
  4. do not communicate with anything or anyone outside of the ARENA.
    5. do not include any form of enabled wireless electronic communication (e.g. radios, walkie-talkies, cell phones,
    Bluetooth communications, Wi-Fi, etc.)
  5. do not in any way affect the outcome of a MATCH, other than by allowing PLAYERS to plan or track strategy for the
    purposes of communication of that strategy to other ALLIANCE members…

Emphasis on the bolded part, unless CPC radios involve extreme tethering.

It’s probably easier to make sure your Router/AP is serving out addresses via DHCP on a 10. that won’t conflict with a team, 10.0.101.XX should be fine, with a subnet mask of Then the DSes with their static IPs can happily talk to the roboRIO with its DHCP address.

Not true. If the WiFi channels are saturated, it doesn’t matter what your IP/subnet you are. You are competing with data trying to use the same pipe (channel) to go somewhere else.

What you are saying is true if you had hard wire and a switch. The switch can isolate sub-nets to maximize data throughput within the sub-net.

WiFi is like a shared wire. Nothing you can do if the wire is saturated.

The DHCP address range can be an issue ONLY if you are planning to use the same SSID as used by FMS and the robots. Clearly, you should not be doing that, even if you could. So, IP addresses are not an issue.

The issue is whether you are using the same RF channels that are being used by FMS. FMS typically uses low numbered channels in the 5 GHz band. If someone else was also using this particular channel, then the bandwidth available for robots could be reduced. FMS typically uses one channel, but may use multiple bonded channels (I heard). Depends on the FTA.

So, using the 2.4 GHz band WILL not cause problems for robots if you use FCC approved AP devices. FCC testing verifies that the device will not transmit radio energy in other ranges. The image posted by jvdiv shows the 2.4 GHz band (Channels 1 - 14). Please scan the 5 GHz range as well, I am sure your school uses channels in this range as well. This info will be useful to the FTA.

Using 5 GHz (Channels > 14) SHOULD not cause problems either as long as you don’t use the channel(s) used by FMS. These channels do not overlap like the 2.4 GHz channels.

If there is a problem, find the real cause. Don’t be a Luddite. There is a lot of unjustified FUD in this area and a lot of people repeat incorrect info that they hear from other uninformed people. Unfortunately, this serves to distract focus from the real problems and delays a good solution. :mad:

This is a week-0 event, without official FRC hardware and no FTA. Depending on their specific setup, they may indeed be using the 2.4 ghz range. Providing General advise is good, getting super specific without knowing the local setup is not.

Sorry, I came back to edit my post and found your speedy response. Since the field would be using 2.4 GHz, my update is to agree that it would be wise to clear one of the 3 channels and dedicate it to FMS.