other interrupts in rc channel reader

Question

I have the sketch from James Waldby (Read RC receiver channels using Interrupt instead of PulseIn) working beautifully. I want to use a switch on my TX to start and stop a sequence of lights (emulating guns firing on a ship model). But first, I need the delayed flash routine to work. I have tried a loop counting millis() differences to separate the sequences, but the delays don't delay.

 void loop(){
 rc_read_values();//Mr. Waldby's interrupt routine
 currentMillis = millis();
 previousMillis = currentMillis;
 if(fireGun ==1){
 interval = 3000;
 }else{
 interval = 1500;
 }
 interval = 3000;
 if (currentMillis - previousMillis >= interval) {
 // save the last time you blinked the LED
 previousMillis = currentMillis;
//if(fireGun ==1){
 analogWrite(led, 255); 
 delay(50);
/* a real gun flash doesn't cut right off; it fades away.
 This sequence simulates that */ 
 while(brightness > 0){
 // change the brightness for next time through the loop:
 brightness = brightness - fadeAmount;
 analogWrite(led, brightness);
 delay( 7); 
 }
 brightness = 80;
}

The intention here is to flash the led every 3 seconds. The flash loop works fine, but the 3 second delay doesn't.

The delay routine works ok in a sketch by itself.

Any thoughts about what I might be doing wrong?

• jsotola: go through the loop() code listing step by step ... write values of variables on a sheet of paper as you go along

Answer 1

 currentMillis = millis();
 previousMillis = currentMillis;

So currentMillis and previousMillis will always be exactly the same, right?

 if (currentMillis - previousMillis >= interval) {

So if 0 >= interval (which it won't be) do something?

Therefore your fading code will never be executed.