Some questions on the legality of Wifi

[The Doctor]

As a programmer, working with bluetooth is really hard compared to hosting something like a webserver. That's why I wasn't too interested in it...

I've looked into options to have a wired connection to the device, but most tablet-compatible ethernet connections are pretty bulky. The other option is to buy some kind of alternate RF module and then write a custom stack to handle comms, but that would be way more work than we need this season.

[FrankJ]

The field uses 5g. Any use of that spectrum in the pits will be frowned upon.

[D_Price]

In conjunction to what everyone else on this thread has said in regards to the violations. Your best bet, at the regional or even before, speak with the Head Regional Director or the field guys to see if they have a spectrum you may borrow while at the competition whether its at a certain time or not.

Originally Posted by FrankJ

The field uses 5g. Any use of that spectrum in the pits will be frowned upon.

[FrankJ]

Originally Posted by D_Price

In conjunction to what everyone else on this thread has said in regards to the violations. Your best bet, at the regional or even before, speak with the Head Regional Director or the field guys to see if they have a spectrum you may borrow while at the competition whether its at a certain time or not.

The FTA is the person to speak with. With all the pressures of keeping the event on schedule, he (she) is the one running around with his head on fire. Safe bet his answer will be no. Aside from not having the time, how can he fairly give one team access, in violation of games rules, without opening it up for other teams?

[Collin Fultz]

Originally Posted by FrankJ

The FTA is the person to speak with. With all the pressures of keeping the event on schedule, he (she) is the one running around with his head on fire. Safe bet his answer will be no. Aside from not having the time, how can he fairly give one team access, in violation of games rules, without opening it up for other teams?

Frank speaks the truth. T4 is very clear. Don't set it up at the venue. Plan for something else.

[jojoguy10]

I saw this during CES: http://cassianetworks.myshopify.com/...c51803009fe0b5

It could be a very good solution since it can handle up to 22 devices and a 1000ft radius.

If any teams end up using it, they should post their results here or somewhere. I'm really curious about this product.

[EmileH]

Even though you'd still be dealing with the issues of range, you could create a Bluetooth PAN network between your tablets for sync up. Bluetooth PAN gives each device an IP address that you could use to run a web server on. To solve the distance issue, have your pit scouters take down data and save it locally to their tablet/phone/device (via the app YOU make), then have them meet with the head scout (during lunch or a match break) and connect to the head tablet/computer via Bluetooth PAN. From there, use your app to sync the stored data and send it to the web server in whatever fashion you like.

EDIT: If you plan on using all Android tablets, make sure they are running 4.0 or later, and do the following for each:

On the PAN host: Enable bluetooth tethering in the settings (If the host is a tablet, you may not find this feature. Try an app like BlueVPN if you're setting it up on a tablet.)
On each device: Pair with the host and enable "Internet access" in the bluetooth device's tab. (This will allow LAN communications between devices).

Credit to ce4 on StackExchange for the answer.

If you so choose, you can also use this method to share Web access from the PAN host (if it is a cell phone) to your PAN devices.

[peterl]

Originally Posted by jojoguy10

I saw this during CES: http://cassianetworks.myshopify.com/...c51803009fe0b5

It could be a very good solution since it can handle up to 22 devices and a 1000ft radius.

If any teams end up using it, they should post their results here or somewhere. I'm really curious about this product.

I looked into it further, but I am still left with questions. Can you control the smart home devices via their native apps, and if so, does it allow for data transfer to a computer using OBEX FTP? Does it allow for a PAN/LAN like setup so they can access a FTP server on my laptop? I know it isn't released yet, but if someone can point me in the right direction, thanks.

[cbale2000]

As a note to those of you considering Bluetooth, keep in mind that Bluetooth operates in the same 2.4GHz frequency range as traditional WiFi. While potentially harder for field staff to detect (as a WiFi scanner will not see it), if it is detected you will likely be told to stop using it.

I came across an interesting paper that describes, amongst other things, how WiFi and Bluetooth interact with each other: http://www.hp.com/rnd/library/pdf/Wi...oexistance.pdf

[techhelpbb]

Originally Posted by cbale2000

As a note to those of you considering Bluetooth, keep in mind that Bluetooth operates in the same 2.4GHz frequency range as traditional WiFi. While potentially harder for field staff to detect (as a WiFi scanner will not see it), if it is detected you will likely be told to stop using it.

I came across an interesting paper that describes, amongst other things, how WiFi and Bluetooth interact with each other: http://www.hp.com/rnd/library/pdf/Wi...oexistance.pdf

The FRC field is not 2.4GHz it is 5GHz.
Of this I can be pretty sure as I have been a CSA/FTAA.

However feel free to take FIRST's word on it:
http://www.firstinspires.org/sites/d...-frc-qanda.pdf
See Q301.

Keep in mind the field security monitoring tools can still detect the 2.4GHz spectrum but usually we don't police it.

When there were issues in the past with the interference the source that caused the most public examples were all interacting with the 5GHz spectrum. Airport radar can also interfere with the top few channels of that 5GHz spectrum.

Also this 802.11n supports channel bonding which is usually turned on but occasionally has been turned off in the past.
So that means that your robots can use 2 channels of that spectrum to get extra radio bandwidth.
That still does not remove the 7Mb limit imposed between your robot and the field.
That bandwidth restriction is imposed not at the radio level but at the protocol level.

[epylko]

Originally Posted by techhelpbb

When there were issues in the past with the interference the source that caused the most public examples were all interacting with the 5GHz spectrum. Airport radar can also interfere with the top few channels of that 5GHz spectrum.

Those (United States) channels are:

• 52 (5260 MHz)
• 56 (5280 MHz)
• 60 (5300 MHz)
• 64 (5320 MHz)
• 100 (5500 MHz)
• 104 (5520 MHz)
• 108 (5540 MHz)
• 112 (5560 MHz)
• 116 (5580 MHz)
• 120 (5600 MHz)
• 124 (5620 MHz)
• 128 (5640 MHz)
• 132 (5660 MHz)
• 136 (5680 MHz)
• 140 (5700 MHz)

Originally Posted by techhelpbb

Also this 802.11n supports channel bonding which is usually turned on but occasionally has been turned off in the past.
So that means that your robots can use 2 channels of that spectrum to get extra radio bandwidth.
That still does not remove the 7Mb limit imposed between your robot and the field.
That bandwidth restriction is imposed not at the radio level but at the protocol level.

It's something that is set by the access point. You can set your client to be able to use 40Mhz channels but if the AP doesn't have 40Mhz channels enabled, you won't get any benefit.

Finally, 80Mhz channels are possible with the 802.11ac Wave 2 access points which can give you an association speed of almost 3.5Gbps.

[jkoritzinsky]

You guys should take a look at SuperScouter. It allows data transfer over QR codes (and customizable data forms). Take a look at http://jkoritzinsky.github.io/SuperScouter4FRC

[FrankJ]

Originally Posted by FrankJ

The FTA is the person to speak with. With all the pressures of keeping the event on schedule, he (she) is the one running around with his head on fire. Safe bet his answer will be no. Aside from not having the time, how can he fairly give one team access, in violation of games rules, without opening it up for other teams?

It was pointed out to me that the FTA and anybody else for that matter does not have the authority to allow teams to violate the rules. T4 is pretty clear. The answer will not be T4 does not apply to you.

[philso]

Originally Posted by FrankJ

It was pointed out to me that the FTA and anybody else for that matter does not have the authority to allow teams to violate the rules. T4 is pretty clear. The answer will not be T4 does not apply to you.

There is a time to think outside the box. Then there is a time to think inside the box.

[FrankJ]

Originally Posted by philso

There is a time to think outside the box. Then there is a time to think inside the box.

Could you use a Farady cage instead?