Serial.println gives wierd results

Forum 2005-2010 (read only) General Frequently-Asked Questions
#1

Im using a potentiomenter to adjust the blinking rate of my diode, and im trying to output the read values + the modified time value into my serial monitor, but it gives me some wierd numbers.

sensorValue ranges from 0-1024

heres what i get from the monitor

sensor = 0
timer = 0
-1279
sensor = 9
timer = 2295
-1279
sensor = 93
timer = 23715
-1279
sensor = 1023
timer = -1279
-1279

  Serial.print("sensor = " );                       
  Serial.println(sensorValue);
  Serial.print("timer = " );                       
  Serial.println(sensorValue*255); 
  Serial.println(1023*255); // added a test to see if it was the read value causing the errors.
  delay(sensorValue*255);

Is there a limitation on how large an integer the println can print? Or am im doing it wrong ?

Please help :)

-Thomas

#2

What types are the variables defined as? The type will determine how big the number can be before it starts rolling off bits.

#3

the sensorValue is an int What datatype would be ideal for this purpose

i remember in other languages the limitations for integers was 64k; -32 -- 32k. does this apply for the arduino syntax?

#4

I poked around in reference and changed the sensorValue to a long, and added another long to store the modified value. now it outputs the correct value.

#5