Xbee.h returning incorrect ADC values

Projects Networking, Protocols, and Devices
1

I am trying to modify the tweet-a-watt project and push the data to pachube with an Ethernet shield instead of sending to twitter from my PC. I'm having some trouble reading the analog inputs 0 and 4 (volts and amps). I have the xbee Tx is setup just like the Tweet-A-Watt project calls for:
MY=1, SM=4, ST=3, SP=C8, D4=2, D0=2, IT=13, IR=1

I'm basically using the XBee_Test_IOSamples sketch that comes with Xbee.h library to read the data. When I read xbee analog inputs, I get this:
Volts = ( 163.00 211.00 322.00 489.00 650.00 766.00 826.00 837.00 785.00 665.00 493.00 335.00 224.00 172.00 164.00 226.00 351.00 524.00 679.00 )
Current = ( 322.00 489.00 650.00 766.00 826.00 837.00 785.00 665.00 493.00 335.00 224.00 172.00 164.00 226.00 351.00 524.00 679.00 0.00 0.00 )

You'll notice that the current values are the same as the voltage values, just shifted two spots to the left. Anyone know what I am doing wrong?

Here's my sketch:

#include <XBee.h>
XBee xbee = XBee();
Rx16IoSampleResponse ioSample = Rx16IoSampleResponse();

void setup() {
  xbee.begin(9600);
}

void loop() {
  float volts[19];
  float current[19];
 
  //attempt to read a packet
  xbee.readPacket();

  if (xbee.getResponse().isAvailable()) {
    // got something

    if (xbee.getResponse().getApiId() == RX_16_IO_RESPONSE) {
      xbee.getResponse().getRx16IoSampleResponse(ioSample);

      Serial.print("Received I/O Sample from: ");
      Serial.println(ioSample.getRemoteAddress16(), HEX);

      Serial.print("Sample size is ");
      Serial.println(ioSample.getSampleSize(), DEC);

      for (int k = 0; k < ioSample.getSampleSize(); k++) {
          volts[k] = ioSample.getAnalog(0, k);
          current[k] = ioSample.getAnalog(4, k);
      }
     
      // Print array with voltage and current ADC values from Xbee
      Serial.print("Volts =   ( ");
      for (int i = 0; i < samples; i++) {
          Serial.print(volts[i]);
          Serial.print(" ");
      }
      Serial.println(" )");
      Serial.print("Current = ( ");
      for (int i = 0; i < samples; i++) {
          Serial.print(current[i]);
          Serial.print(" ");
      }
      Serial.println(" )");
     
    }
    else {
      Serial.print("Expected I/O Sample, but got ");
      Serial.print(xbee.getResponse().getApiId(), HEX);
    }
  }
  else if (xbee.getResponse().isError()) {
    Serial.print("Error reading packet. Error code: ");
    Serial.println(xbee.getResponse().getErrorCode());
  }
}
2

Where is samples defined? Where is it assigned a value?

It looks like you are reading the number of samples from the packet, and then printing a fixed number of values, and that the number of samples and the fixed number of values do not match.

3

Sample size is pulled from the xbee data using ioSample.getSampleSize()

4

Sample size is pulled from the xbee data using ioSample.getSampleSize()

Where?

      for (int i = 0; i < samples; i++) {
          Serial.print(volts[i]);
          Serial.print(" ");
      }

Show me where, in the code you posted, samples is declared, and where it is assigned a value.

5

I guess I made a mistake pasting the code to the forum. I was getting samples from ioSample.getSampleSize(). After this problem cropped up I decided to see what would happen with the Xbee_Test_IOSamples sketch that comes with xbee.h library. It shows the same problem. Here's the sketch

#include <XBee.h>
XBee xbee = XBee();

Rx16IoSampleResponse ioSample = Rx16IoSampleResponse();

void setup() {
  xbee.begin(9600);
}

void loop() {
  //attempt to read a packet
  xbee.readPacket();

  if (xbee.getResponse().isAvailable()) {
    // got something

    if (xbee.getResponse().getApiId() == RX_16_IO_RESPONSE) {
      xbee.getResponse().getRx16IoSampleResponse(ioSample);

      Serial.print("Received I/O Sample from: ");
      Serial.println(ioSample.getRemoteAddress16(), HEX);

      Serial.print("Sample size is ");
      Serial.println(ioSample.getSampleSize(), DEC);

      if (ioSample.containsAnalog()) {
        Serial.println("Sample contains analog data");
      }

      if (ioSample.containsDigital()) {
        Serial.println("Sample contains digital data");
      }

      for (int k = 0; k < ioSample.getSampleSize(); k++) {
        Serial.print("Sample ");
        Serial.print(k + 1, DEC);
        Serial.println(":");

        for (int i = 0; i <= 5; i++) {
          if (ioSample.isAnalogEnabled(i)) {
            Serial.print("Analog (AI");
            Serial.print(i, DEC);
            Serial.print(") is ");
            Serial.println(ioSample.getAnalog(i, k));
          }
        }

        for (int j = 0; j <= 8; j++) {
          if (ioSample.isDigitalEnabled(j) && ioSample.containsDigital()) {
            Serial.print("Digital (DI");
            Serial.print(j, DEC);
            Serial.print(") is ");
            Serial.println(ioSample.isDigitalOn(j, k));
          }
        }
      } 
    } 
      
    else {
      Serial.print("Expected I/O Sample, but got ");
      Serial.print(xbee.getResponse().getApiId(), HEX);
    }
  }
  else if (xbee.getResponse().isError()) {
    Serial.print("Error reading packet. Error code: ");
    Serial.println(xbee.getResponse().getErrorCode());
  }
}