The Access Points on the 2009 Control System

[Shadow503]

As many of you who have seen the 2009 control system know, it contains a wireless router and a webcam. This got me thinking, wouldn't it be cool if people in the stands could connect to that access point with their laptops? You could pick a robot and then watch the match from that robot's point of view using the on board webcam.

Some teams already have webcams mounted on their robot, but it would be cool to have this stream available live.

http://youtube.com/watch?v=KRqJT67cHQI
As you can see, a robocam provides an interesting perspective to the match.

Keep in mind that my proposed idea would be illegal under the current rules. I talked to one of the guys from NI at ATL about the technical plausibility of this. He told me it wouldn't be hard to set up and it should work. He also said he'd pass on my idea to the GDC and some other folks at NI.

I think this would be a great way to make the events even more exciting.

[danshaffer]

You just have to watch out for the bandwidth requirements of the WAP... wouldn't want the robot to receive/send less data because it's streaming its video feed to the stands...

[fimmel]

you could have it all feed back to a main server that would keep track of all the feeds and then have a 2nd access point (without security) so the public could connect and see scores and schedules and live video.

kind of like sundial (having live scores and schedules) but adding video support

...forest

[Mr. Freeman]

Sounds like a good idea. As for the bandwidth issue, what about FIRST setting up another server on the field such that this server would read the stream from the robot and everyone wishing to watch the feed would connect to this server rather than the robot itself.

EDIT: fimmel beat me to it.

[tdlrali]

The dashboard laptop could serve as the stream server... except we're not allowed to set up additional wireless networks

[Nibbles]

The biggest problem with access points isn't how many users a single one can support, it is collisions, especially collisions that only the router can see, but each client can not because they are too far away from each other (called a hidden node). What could work is a packet scheduler, where each Wi-Fi node is guaranteed a time slot where no one else will broadcast. With six robot Wi-Fi Nodes (Nodes or access points in 2009?, the field control system would need to connect to six AP's at once), plus six operator interfaces linked via Ethernet to one Wi-Fi access point, could mean quite a slow down with or without collisions.

In short, there is no way we are going to be streaming video, over Wi-Fi at least. Now, however, we get to use 900MHz video broadcast systems, which are much simpler (this assumes that independent 900MHz systems will now be allowed), being the analog TV band (I think...).

Personally I enjoyed the 900MHz network. Wi-Fi is just too complex.

[danshaffer]

Idea: you might be able to tie the robot cams into the stadium video system, so you could at least show botcams on the big screen

[Shadow503]

Originally Posted by danshaffer

You just have to watch out for the bandwidth requirements of the WAP... wouldn't want the robot to receive/send less data because it's streaming its video feed to the stands...

You should be able to use the QoS settings on the router to give priority to the control data.

802.11G has a typical speed of 23 Mbit/s, that should be plenty of bandwidth to stream video.

[gunsanbob]

to tell the truth I would rather watch all the robots

[neutrino15]

I think that if anything, they would stream the robot feeds to their own media server, and project certain feeds onto the big screen.

More likely (hopefully), they will let us communicate with the field, as well as other robots on said field. Then you could wirelessly tell the field, for example, to rotate something, or open a door..

No matter what, though, we will be able to communicate robot-robot (this IS standard TCP/IP).. I say we develop a standard for inter-robot messaging.. Depending on next year's game, we would possibly be able to group up and accomplish certain things together.. Even if it's just to tell everyone on the field some tidbit of information.. Think about it:

Operator Interface -> Robot -> Field Network -> Any Other Robot -> Any Other Operator Interface!

Or

Robot -> Field Network -> Any Other Robot

[yongkimleng]

Hmm my take on this:

1. use smarter nodes for APs. Like those USD$30 fon/meraki devices.
Allows encryption, filtering, etc. We certainly do not want rogue data interrupting the matches.

2. UDP for control. All realtime control protocols use UDP.
(Whats UDP? Google )

3. QoS is necessary. Set control packets to highest priority, video stream to lowest, debug messaging medium, etc

4. Use various channels. There are approx 13 channels, of which some slightly interfere with each other. Now we approx have 54Mbps of capacity per channel. Designing the system to operate at a minimum of 11Mbps or lower would be good coz, in a case where a channel is saturated with colliding data from other networks on that channel, your system will likely to perform constantly. We can have 1 team using 1 channel per match, i.e. when 2 matches are going on simultaneously they would be using 8 channels.