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NXTBee 
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Post NXTBee
We have done geocaching simulation with gps receivers. Now, we are planning to use it to simulate the hide and seek game, almost like the criminal tracking gps device. The search crow-fly distance will be within 1000 feet with a lot of buildings filled with all various wireless within the search path. Since wireless also using 2.4GHz, I would imagine there is a lot of interference. In addition, I just skimmed through the RC car sample code. I could not find how it connects to a selective channel!?

I believe Xander has played with this. Wonder if I can get some insight... Thank you in advance.


Thu Mar 31, 2011 8:01 pm
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Post Re: NXTBee
I have but not over distances like that. I did build in a fair bit of robustness into my protocol, which is something you'll definitely need.
It defaults to channel 0, unless configured otherwise, this allows people to use it out of the box without having to fiddle with it. You can configure it for any one of 16 channels, I believe.

- Xander

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Fri Apr 01, 2011 1:44 am
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Post Re: NXTBee
Hi Xander,

1000 feet is the max that I'd like to test. In the environment where my students and I will play with will be mostly within 300 feet, but around perimeter of building complex. There will be a clear path from one pt to another, but not in direct line of sight though.

robot1
........xxxxxxxxxxxxxxxxx
........xxxx building xxxx
........xxxxxxxxxxxxxxxxx
................................robot2

"...a fair bit of robustness in the protoccol..."

You mean in the application layer only, I hope. Do you mean the robustness to ensure reliability of complete packet delivery with ack and nack proper sequence in the application. Or just with very careful error checking?

When we played with bi-directional communication with bluetooth, we have to pack up quite a bit informaton onto a single byte due to all the lag time delay. Wonder if there will be similar issue.


Fri Apr 01, 2011 8:31 am
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Post Re: NXTBee
I am assuming you are buying the NXTBee Pro versions, right? I am not sure the other one can go that distance. I don't have a Pro versions, only the regular ones.

By robustness I meant being able to recover from having to retransmit a request if the response was garbled. The response is easily verified with a checksum.

Regards,
Xander

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| ROBOTC 3rd Party Driver Suite: [Project Page]


Fri Apr 01, 2011 9:33 am
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Post Re: NXTBee
Yes, I am getting the pro version to test out. I read the spec. Looks like, as far as reliability, they seem to be the same. The pro needs 9V going along with it. But, of course, without testing it... who knows.

But with your experience with the regular one, other than you need to checksum the integrity of the packet, do you experience any visible delay? I am hoping to play with RC based on onboard sensor feedback, i.e. remote controlling it without seeing the bot, but based on the onboard sensors data.


Fri Apr 01, 2011 9:44 am
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Post Re: NXTBee
I was communicating at about 115.2Kbaud, so the delay was negligible. I made a video of it and posted it in my article:
http://mightor.wordpress.com/2011/02/12 ... he-nxtbee/

The code is also in that post :)

- Xander

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| Professional Conduit of Reasonableness
| (Title bestowed upon on the 8th day of November, 2013)
| My Blog: I'd Rather Be Building Robots
| ROBOTC 3rd Party Driver Suite: [Project Page]


Fri Apr 01, 2011 10:01 am
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