int servoPin = A3;

Servo myServo;

bool servoPositionUpdated = false;
int servoPosition = 0;

void setup() {
    
    myServo.attach(servoPin);
    Particle.function("pos", setPosition);

}

void loop() {
    
    if (servoPositionUpdated == true){
        
        myServo.write(servoPosition);
        servoPositionUpdated = false;
        
    }

}

int setPosition(String command){
    
    int value = command.toInt();
    if (value>180) {
        
        return -1;
    }
    if (value<0){
        
         return -1;
    }
    
    servoPosition = value;
    servoPositionUpdated = true;
    
    
}