Let's Make Robots!

Short question about Xbee connections

While sending information from PC to Picaxe (thru xbee's) the connection gets stuck (or you could say lagged) after sending continuous data for a few seconds.


Is this because I am using debug on the picaxe and it slows down the controller or is it because of some other reason?



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The solution was, as stupid as this may sound, to take the robot's xbee module and connect it to the pc and vice versa. This is probably because one of them is programmed as a "router" and the other one as a "coordinator".

To Geir: I actually used the x-ctu to reprogram the xbee's but no precise information on the model was shown on the software. Well, for now, it does not matter that much, I will just need to check the range manually of them.


Anyways, thank you guys for your help and contribution to my projects. You're the best! ;)

Ok, since every method I tried was unsuccessful I'm going to continue asking for assistance, if You don't mind :)

I'm going to write everything in detail, to ensure no misunderstandings.

To cross out the debug I made a little bot made of two continuous rotation servos with wheels, picaxe 28x1 and xbee module. IMAGE

The test-bot is controlled by VB application. IMAGE (the words are in Lithuanian, though should be obvious. (COM connection buttons, and four buttons for controlling the directions including the "STOP" button in the middle in case the bot does not stop.)

The application is very basic : when a directional button is pressed instruction is sent thru COM port and when released it sends a command to stop.

The xbee on the test-bot is connected to the picaxe with the help of adafruit adapter. (note that I checked and the baud rates are set to 2400 on both of the radio modules.) Everything works for a few seconds but then it gets "stuck" for ~7 seconds (robot is not responding to any of commands sent) then it gets normal again for a few seconds. This is repeating.

Any ideas?

Also, I would like to know what kind of xbee's I have got. As far as I know from the guy I purchased the modules they are Zigbee Pro 2.5, but I'm not able to find the model on the net. They seem to look like a 'pro' version, because of the antenna addon, but there's no word "pro" on the modules.


Have you tried the X-CTU utility from http://www.digi.com/ it might help you identify the device?

Yes debug is extremely slow and takes a lot of picaxes resources. (however its possible to a debug on just a single variable)

What i would suggest is to insert a delay after each tx byte just to confirm data can flow albeit slow (use big delay at start then trim to optimum ) - using delays is more of a workaround.

The Xbee has many modes of operation, using my arduino i can throw very high baud rates at it without lag or loss of data,and that is using the factory default values. its a good idea to reset to factory default from time to time as many things "just happen" when delving into the firmware settings.

Sounds like an overflow of a buffer either in picaxe or Xbee - if so then some form of software or hardware "handshake" must be implemented.

Also make sure that all your baud rates match .