Arduino event system

Some time ago, when I was coding hardware project for school, which was model of a garage with gate, I was thinking about an easy way to control 2 things at the same time. Of course it is easy to use for-loop to control servo motor useful for opening gates, but you can only open/close 2 things at once only if they are the same. Unfortunately condition was to open gate and then garage 2 seconds later.

for (int i = 0; i <= 180; i++) {
  servo.write(i);
}

Later that day, I thought about having a boolean variable which would have a state if a garage/gate is open or not. But still I had to thought about asynchronous opening of two things at once.

Then I realized that "void loop()" is similar to having a while loop so I removed for-loop and here we are. For each servo there is a state if it's closed or open and also it's current position which can be used for manipulating the final states.

void loop() {
   if (!openedGate) {
      servo.write(++i);
      if (i > 180) {
        openedGate = true;
      }
   }

   if (!openedGarage) {
      servo2.write(++j);
      if (j > 180) {
        openedGarage = true;
      }
   }
}

A small change in style and code can look really nice. Even C.

void loop() {
  if (event == GATE_OPENING) {
    if (!openedGate) {
      servo.write(++i);
      if (i > 180) {
        openedGate = true;
      } else if (i == 1) {
        openingGateTime = millis();
      }
   }

   if (!openedGarage && millis() - openingGateTime > 2000) {
     servo2.write(++j);
     if (j > 180) {
       openedGarage = true;
     }
   }
  }
}

Problem with this technique is that Arduino and it's MCU (ATMega328p) is pretty slow and only 8-bit (also it is underclocked for convinience sake of Arduino community), which is for most cases okay, but printing on LCD at the same time opening 2 gates can be pretty tough for this little boy (Can be achieved by heavy optimalization and little mind push).

Source code of this project is available here.