Xbee / Arduino Uno Drops Letter P

Wireless & IoT
1

Yes! That’s right, my simple setup is dropping lower case “p”. This has to rank as one of the dumbest problems I’ve had in my 20+ years as a programmer.

I have a fairly simple setup. An UNO with an XBee S1 Pro attached via an xbee shield. This device reads an analog value from a pot and sends it via serial to my other UNO with an XBee s1 Pro. It sends a string like “Reporter r1:Temperature:123”. On the receiving end, I receive one of the following:

Reporter r1:Temperature:123

Reorter r1:Temperature:123

Reporter r1:Temerature:123

Reorter r1:Temerature:123

If I change the string that is being transmitted to upper case, it doesn’t happen. If I change the lower case “p” to “s”, it doesn’t happen.

Have I finally gone insane?

Any help or direction would be greatly appreciated.

2

As always, what’s the code behind all of this? In particular, the baudrate settings. If you are using high baudrate, then this may apply:

http://www.digi.com/support/forum/4787/ … march-2010

3

Thank you for responding. There are a lot of supporting classes so I’ll simply include the main loop on the receiving device:

void loop()

{

if(XBee.available()) {

incomingData = XBee.readString();

if(incomingData != “”) {

Serial.println(network.getLabel() + “:” + logger.formatResults(incomingData));

Serial.println(incomingData); // This will also print the erroneous string

} else {

Serial.println(“Xbee available, no data”);

}

digitalWrite(ledRXPin, LOW);

} else {

digitalWrite(ledRXPin, LOW);

}

}

Note the two Serial.println() calls. The first is the original code and the second was to quickly see if I was goofing something up.

Here is the sending device setup and main loop:

void setup()

{

Serial.begin(BAUD_RATE);

XBee.begin(BAUD_RATE);

pinMode(13, OUTPUT); // We simply blink the 13 led when we send data

// 1. Here we are directly setting the label that will help us visually identify

// this reporting board when looking at the data.

reporter.setLabel(“Reporter R1”);

// 2. Add a sensor to the collection. This is an analog sensor attached to port 0. We

// are giving in an arbitrary ID of 1.

my_sensor_collection.addSensor(1, 0, PIN_TYPE_ANALOG, “Potentiometer”);

my_sensor_collection.addSensor(2, 1, PIN_TYPE_ANALOG, “Temperature”);

}

void loop()

{

ESN_Sensor current_sensor;

/**

  • All of the following is left as is as we have yet to determine a format. We have to take

  • readability (machine) into account as well as dealing with this data collision issue.

*/

// Reset the internal pointer on the sensor collection

my_sensor_collection.reset();

digitalWrite(13, HIGH);

// Loop through all the sensors

for(int i = 1; i < my_sensor_collection.getSensorCount() + 1; i++) {

// Get the current sensor

current_sensor = my_sensor_collection.getNextSensor();

Serial.println(reporter.getLabel() + “:” + current_sensor.getLabel() + “:” + (String) current_sensor.readValue().value);

// The logger has an issue parsing lines based on \n character. For this reason, we are going to send sensor data one reading

// at a time.

delay(TRANSMIT_DELAY);

}

digitalWrite(13, LOW);

}

If you look at the setup method on the “sending” device, I will have problems with those "p"s. However, I changed it to REPORTER R1 and the sensors to TEMP and POTS and I have not seen a problem in 3 days. That’s about 10,000 transmissions.

The Baud rate is 19200. I raised in attempt to deal with data collisions. The idea is to run 10 - 20 “sending” devices.

Thanks again for any help. I can make due with using caps but I sure would like to know what the heck is going on.