Impossible communication with Arduino Xbee (PhysicalPixel example)

Projects Programming
1

Hi,
I'm starting using Arduino. I have 2 Arduino UNO R3 and 2 Xbee Pro S2B. I have a problem when I iniciate the communication between Xbees with "PhysicalPixel" basic example for the receiver. The transmitter uses the following code:

void setup()
{
Serial.begin(9600);
}

void loop()
{
Serial.print('H');
delay(1000);
Serial.print('L');
delay(1000);
}

I can communicate with my PC, but when I disconnect USB wire and later I try to connect again, I have to open the "Monitor Serial" to allow them transmitting or receiving again.
So, if I want to provide a different alimentation (independent from the computer), they will not communicate each other because I can't open the "Monitor Serial".
Could anyone help me?

Thanks.

2

How are the XBees attached to the Arduinos?

3

With the Shield Xbee, the same as the picture which is uploaded in the following link, but I also have one antenna per Xbee:

http://www.google.es/imgres?q=arduino+xbee+pro&um=1&hl=es&client=firefox-a&rls=org.mozilla:es-ES:official&biw=1366&bih=651&tbm=isch&tbnid=b4AFaQ3iHu945M:&imgrefurl=http://www.geekonfire.com/index.php%3Fmain_page%3Dproduct_info%26products_id%3D24&docid=o441Na3M47XZwM&imgurl=http://www.geekonfire.com/images/Desktop_20110831/A2011083103_2.jpg&w=400&h=320&ei=GZ0GUNKMH8vcsgbG5rjBBg&zoom=1&iact=hc&vpx=551&vpy=216&dur=1437&hovh=201&hovw=251&tx=118&ty=66&sig=109041842847560529074&page=1&tbnh=145&tbnw=195&start=0&ndsp=18&ved=1t:429,r:2,s:0,i:75

Thanks for your answer.

4

I can communicate with my PC, but when I disconnect USB wire and later I try to connect again, I have to open the "Monitor Serial" to allow them transmitting or receiving again.

How are you powering the Arduinos, when the USB cable is disconnected?

When you unplug the cable, do the XBees continue talking to each other?

What setting(s) are the jumpers on?

5

I will try to answer your questions:

How are you powering the Arduinos, when the USB cable is disconnected?:

  • I only have one USB wire so, one Arduino is powered by this wire and the other one is powered by a 9V battery.

When you unplug the cable, do the XBees continue talking to each other?:

  • Indeed, they can not communicate yet. As I said before, I only have one USB wire and they can not communicate using batteries.
    In conclusion, they never have communicate each other before.

What setting(s) are the jumpers on?

  • When I upload the code, jumpers are on the USB location (position). When I want to communicate something, they are in Xbee position.

Really thanks for your help. Sorry for my English.

6
  • I only have one USB wire so, one Arduino is powered by this wire and the other one is powered by a 9V battery.

Put the 9V battery back in the smoke detector you stole it from, and get a real battery pack (4 AAs work well) or a 7.5V wall wart.

Indeed, they can not communicate yet.

So, you have no proof that the XBees are properly configured? You don't know that they can talk to each other at all?

I'm confused about what you can, and can not do. Opening the serial monitor to get the XBees to talk to each should not be necessary. My Arduinos, with XBees, communicate just fine with a proper power supply (4 AA batteries) and proper configuration. No PC(s) involved at all.

7

Hi again mate,

On one hand, I just thought about the question "Do I have any proof about the properly configuration of the XBees?" and I tried to configurate them with X-CTU and the Monitor Serial but, when I key in "+++" I have never be answered with "OK" (I receive nothing).

On the other hand, I have read that my XBee can be "bricked" and I have just followed all the steps to get my XBee "un-bricked".
This is the answer I always get:

Getting modem type....OK
Programming modem...Detected baud rate difference.
Make sure PC and modem baud rate is set correctly
Lost communication with modem
Write Parameters...Failed

Thanks you for your patience mate.

8

How are you connecting the XBee to the PC when using X-CTU?

9

XBees are connected with one shield and the Arduino UNO, then I connect Arduino with the USB wire.
Jumpers are in USB position, although I have tried in XBee position too.

10

XBees are connected with one shield and the Arduino UNO

With or without the AtMega328 chip installed? When using that shield on the Arduino, with X-CTU, you must remove the AtMega328 chip. Be careful to note which way the chip is installed, so you can put it back correctly after configuring the XBees.

Or, get something like this: SparkFun XBee Explorer USB - WRL-11812 - SparkFun Electronics