Need two-way comm with Xbee

Projects General Guidance
1

Okay, let me start by saying I just started working with these modules that were given to me by a friend. I have two Xbees, an Xbee shield v1.2 and a USB Xbee adapter. So I have connected the USB adapter with an Xbee to my PC, confirmed it shows up and usb/serial port com14. I then loaded a sketch provided by Seeed on the arduino, see below.

/*
Example from Arduino SoftwareSerial tutorial
 */
#include <SoftwareSerial.h>

SoftwareSerial mySerial(11, 12); // RX, TX

void setup()  
{
  // Open serial communications and wait for port to open:
  Serial.begin(9600);
  mySerial.begin(9600);
}

void loop() // run over and over
{
  if (mySerial.available())
    Serial.write(mySerial.read());
  if (Serial.available())
    mySerial.write(Serial.read());
}

So what this all does is I open the serial connection to the bee plugged into my computer and with the arduino connected via USB I opened a serial monitor in the IDE.

When I type something in the putty window, it shows up in the serial monitor of the Arduino. Pretty cool really.

So what I want to do ultimately is connect some sensors to my arduino and send a string from my computer that tells the arduino I want sensor data. It doesn't have to be streaming data, just the numbers from the sensors at the moment I asked for them. So when the arduino receives the "Send me data" string, it sends back the data. Basically a wireless weather station. But I don't want the arduino to transmit data unless I ask for it. Does this make sense?

I'm going to start out with a photoresistor just to return some arbitrary numbers that I can see changing.

Thanks in advance everybody.

2

But I don't want the arduino to transmit data unless I ask for it. Does this make sense?

Yes, and the XBees are perfectly capable of that.

What is the problem?

3

PaulS:
Yes, and the XBees are perfectly capable of that.

What is the problem?

There's not really a problem, I just haven't figured out how to do it yet. As you can see from the very basic sketch I pasted, it's just a two-way serial print. I can send characters from putty over the local radio to the radio on the arduino and they print on the serial monitor as I type them, likewise I can type a string in the serial monitor and click "send" and it shows up on the putty screen.

I'm just not sure how to send a query to the arduino over this and get my sensor data back. Let's say I have a photoresistor set up on the arduino taking measurements of ambient light every 10 seconds or so and I want to send a string to the arduino for the most recent measurement. What would the syntax be for that, assuming my commands were just a specific string for example, I send "GetLightLevel" or shorten it to "GL". How do I modify the code to recognize "GL" as a command?