   }
   
   #ifdef DEBUG
-  if ((millis() - timer) > INTERVAL && chan == 0) {
+  if ((millis() - debug_timer) > DEBUG_INTERVAL && chan == 0) {
       // timed out
-      timer += INTERVAL; // reset timer by moving it along to the next interval 
+      debug_timer += DEBUG_INTERVAL; // reset timer by moving it along to the next interval 
   	Serial.print(rcChannels[0]); 
   	Serial.print("\t");
   	Serial.print(rcChannels[1]); 

//  divided by 2 to get the number of microseconds
#define TIMER_COUNT_DIVIDER 2 

volatile boolean triggered;
volatile uint16_t counter;
uint16_t pulse;
uint16_t last;
boolean first = true;
unsigned long timer; // the timer
uint16_t INTERVAL = 1000; // the repeat interval

// this array contains the lengths of read PPM pulses in microseconds
uint16_t rcChannels[RC_CHANNELS_COUNT];

// Use for Futaba transmitters (they have shifted center value and narrower range by default)
//#define FUTABA

// Uncomment to enable output of PPM values to serial
//#define DEBUG

#define RC_CHANNELS_COUNT 6
