Hi there @johnnytechknow! You're currently on the phone with @arnold_robolink, but I wanted to link you to the lesson that includes a killswitch in the loop() function. But as he said, when the drone goes up to the ceiling, what's happening is a suction force that keeps it stuck on the ceiling. Throttling down won't be strong enough to make it descend in this case, so having a killswitch is always key. You'll need to put the killswitch in the loop() function of your Arduino code, so that it's constantly checking for input.
I'll post the code here, and also link you to the lesson on Basecamp.
void loop () {
/* Start of the kill switch*/
byte bt8 = digitalRead(18);
byte bt4 = digitalRead(14);
byte bt1 = digitalRead(11);
if(bt1 && bt4 && !bt8){
CoDrone.FlightEvent(Stop);
}
/*end of kill switch*/
}
@arnold_robolink if there's anything I've missed, please supplement with anything else.