Axon II and Xbee Connectivity

[webgeek]

I apologize for this being a dumb question but I'm very nervous about getting the right components so I'm hoping one of you has done this before and can vet my decision.

I'm looking to use a computer to send and receive wireless information from my Axon II. I don't need to communicate with more than one device so I don't need to support the whole "mesh" thing. I'd like to keep this as simple and straightforward as possible. To that end, here are the devices I've chosen:

1 x XBee USB Explorer - for connecting the computer to the XBee via USB
http://www.sparkfun.com/commerce/product_info.php?products_id=8687

1 x XBee Explorer Regulated - for connecting the Axon II to the XBee
http://www.sparkfun.com/commerce/product_info.php?products_id=9132

2 x XBee 1mW Chip Antenna - actual radios
http://www.sparkfun.com/commerce/product_info.php?products_id=8664

OR

2 x XBee Pro 60mW Chip Antenna - actual radios
http://www.sparkfun.com/commerce/product_info.php?products_id=8690

My question is simple: did I pick the right devices and will these work easily with the Axon II directly? If not, what should I get? Thanks!

-Mike

[waltr]

I use a similar set-up to get data from my bot (running a PIC) to the PC. The 1mW XBee works well. It is a Series 1 module running the 802.15.4 protocol which is prefect for your application.  The 60mW XBee might be too much as it will quickly drain your bot's battery.

Some people have had issues with the regulated breakout and the Axon. Here is a link to the discussion:
http://www.societyofrobots.com/robotforum/index.php?topic=9790.0

[Admin]

I'd like to keep this as simple and straightforward as possible.

I'd recommend Bluetooth to be honest, as in the bluetooth-Axon tutorial video.


One thing a lot of people don't consider is during robot competitions when many people are using XBee simultaneously. They report serious cross-interference with the devices. Bluetooth however can handle, if I remember right, 100 devices at the same time no problems at all.

[HyperNerd]

I somehow doubt that statistic

Whenever I've used bluetooth on a robot (Lego NXT ) everything interferes with it. My WLAN, wireless headphones, wireless camera, even the microwave .

P.S We are a very wireless household!

 -HyperNerd

[Admin]

Whats the range/class on your NXT bluetooth?

I used a class 1 bluetooth at RoboGames 2009 with probably 30-40 other bluetooth devices operating around me at the same time. Not a single glitch even at 50m+ away

[HyperNerd]

According to the Wikipedia page, it is class 2 bluetooth (not sure on range).

I was using it from my computer upstairs with a 100m range (not sure on class this time ) bluetooth usb dongle, with the robot driving around in a room down the hall, and the bluetooth was iffy.

Maybe I live in a lead house

 -HyperNerd

[Admin]

Well, a class 2 has a range of less than 33 feet - without walls in the way.

Sounds like you were bordering that.

[HyperNerd]

That range is embarrassing for a device which is the size of a brick and weighs as much as 2 cars.

 -HyperNerd

[webgeek]

The problem now is that I've heard complaints with both BlueTooth and XBee (though the first XBee one I've heard is from you in this thread). I'm open to using either, I simply want to pick one and stick with it. As this is for RoboGames and that's likely the only place I'll run into interference. Here is the thread with a few complaints on BlueTooth at RoboGames last year:
http://forums.trossenrobotics.com/showthread.php?t=3769

So if I went BlueTooth, are these the right parts?

BlueTooth on mech:
http://www.sparkfun.com/commerce/product_info.php?products_id=582

BlueTooth on computer:
http://www.sparkfun.com/commerce/product_info.php?products_id=8180

Another question:

They report serious cross-interference with the devices.

Do you mean data transmission issues or connectivity issues? I do a lot of protocol programming for a living and have zero concerns writing a low level protocol that can handle massive message loss but I can't do anything if there are connectivity issues.  Thanks!

Mike

[Admin]

My bluetooth setup:
http://www.sparkfun.com/commerce/product_info.php?products_id=158
http://www.sparkfun.com/commerce/product_info.php?products_id=145

My PC used the Asus Bluetooth class 1 Dongle WL-BTD201M. I got it from newegg, but they don't seem to have it anymore . . .

Do you mean data transmission issues or connectivity issues? I do a lot of protocol programming for a living and have zero concerns writing a low level protocol that can handle massive message loss but I can't do anything if there are connectivity issues.  Thanks!

Massive packet loss caused by everyone transmitting at the same frequency . . . 2.4Ghz cameras, 2.4Ghz bluetooth devices, 2.4GHz remote control transmitters, 2.4GHz xbee transmitters, you name it!

[madsci1016]

The case where all the Xbee's where stepping on each other, were they the newer 2.5 series? They are suppose to support DSSS (Direct Sequence Spread Spectrum) and retransmit and not have that problem.

We use FreeWave here at work, and we have seen FreeWave knocking out Xbee's but that is from sheer transmit power knocking out little transmitters.

[KurtEck]

I was having problems with the XBee V1 with the Sparkfun regulated with the Axon2.  I tried it for awhile and then I swapped in a AppBee Sip that is made by www.selmaware.com and it is now working.  I have had luck with the Sparkfun ones with my Basic Atom Pros, but so far not with the Axon.  I think I read in a different thread that there is a problem that the sparkfun may not get the low level signal low enough for the Axon.

I have been playing around with XBees with an Xbee version of the DIY Remote control (lynxmotion.net).  I now have my XBEE packet code converted over to C and it is running on the Axon2.  Next up is to finish porting the Brat code over...

Good Luck
Kurt