   }
   
   // check AOA value and set tone and pauses between tones according to 
-  if(AOA >= 90) {
-    // play 20 pps 1600hz tone
+  if(AOA >= HIGH_TONE_AOA_STALL) {
+    // play 20 pps HIGH tone
     highTone = true;
-    setPPSTone(20);
+    setPPSTone(HIGH_TONE_STALL_PPS);
     toneMode = PULSE_TONE;
-  } else if(AOA >= 70) {
-    // play 1600hz tone at Pulse Rate 1.5 PPS to 6.2 PPS (depending on AOA value)
+  } else if(AOA >= HIGH_TONE_AOA_START) {
+    // play HIGH tone at Pulse Rate 1.5 PPS to 6.2 PPS (depending on AOA value)
     highTone = true;
     OldValue = AOA-69;
     toneMode = PULSE_TONE;

// We use our own counter for how often we should pause between tones (pulses per sec PPS)
int cycleCounter = 0;
int cycleCounterResetAt = FREQ_OF_FUNCTION;
void tonePlayHandler(){
  cycleCounter++;
  // check if our counter has reach the reset mark.  if so flip the tone on/off and start again.

    NewRange = HIGH_TONE_PPS_MAX - HIGH_TONE_PPS_MIN; // (NewMax - NewMin)  
    NewValue = (((OldValue - 1) * NewRange) / OldRange) + HIGH_TONE_PPS_MIN; //(((OldValue - OldMin) * NewRange) / OldRange) + NewMin
    setPPSTone(NewValue);
  } else if(AOA >= LOW_TONE_AOA_SOLID) {
    // play a steady LOW tone
    highTone = false;
    toneMode = SOLID_TONE;
  } else if(AOA > LOW_TONE_AOA_START) {
    toneMode = PULSE_TONE;
    highTone = false;
    // play LOW tone at Pulse Rate 1.5 PPS to 8.2 PPS (depending on AOA value)
    // scale number using this. http://stackoverflow.com/questions/929103/convert-a-number-range-to-another-range-maintaining-ratio
    OldValue = AOA-20;
    OldRange = 40 - 1;  //(OldMax - OldMin)  
