// Copy allof this ctrl A then ctrl C
// then open your arduino IDE and paste ctrl V

#include <Servo.h>                              //imports the servo library
#include <EEPROM.h>                             //imports the EEPRom library

//setup the servo
Servo myservo;                                  //give the servo a name
int pos = 120;                                  //tell the servo its starting position
int endPos;                                     //will be used to store the trimmed servo end position

//set up the trigger switch
byte TrigPin = A0;                              //which pin it will connect to on the nano
int TrigRead = 1;                               //what state the trig switch is in 1 = vernier in holder 0 = vernier in use

//set up the mode switch
byte modePin = A1;                              //which pin it will connect to on the nano                              
int mode = 0;                                   //what state the mode switch is in 1 = in setup mode 0 = normel operation

//set up the potentiometer
byte trimPin = A2;                              //which pin it will connect to on the nano
int trimReading;                                //will be used to store the reading from the potentiometer

//this section only runs on initial start up
void setup() {
  endPos = EEPROM.read(0);                      //read the saved value of the potentiometer from the nano memory
  myservo.attach(9);                            //tell the nano what pin theservo is connected to
  Serial.begin(9600);                           //start the serial monitor
  pinMode(TrigPin, INPUT);                      //tell the nano the trigger pin is an input
  pinMode(modePin, INPUT);                      //tell the nano the mode pin is an input
  pinMode(trimPin, INPUT);                      //tell the nano the trim pin is an input
}

// this is the loop, it is what runs round and round
void loop() {
  mode = digitalRead(modePin);                  //read the mode pin and store the reading 1 or 0
  if (mode == 1) {                              //if the reading from above is a 1 do from {
    trimming();                                 //to here } // this will go to the trimming function
  } else {                                      //if the reading was a 0 do from {
    running();                                              // this will go to the running function
  }                                             //to here }
}

//this is the function that controlls the servo for the setup process
void trimming() {
  while (mode == 1) {                           //while themode switc read is 1 it will stay in thei loop
    Serial.println("In setup mode.");           //lets you know you are in setup mode in the serial monitor
    trimReading = analogRead(trimPin);          //reads thevaluefrom the potentiometer
    endPos = map(trimReading, 0, 1024, 0, 45);  //takes the value of the potentiometer of 0-1024 and maps it to values from 0 - 45
    Serial.println(endPos);                     //tells you how much you have adjusted it in the serial monitor
    myservo.write(endPos);                      //tells the servo to go to the mapped end positiom
    mode = digitalRead(modePin);                //reads the mode pin to check if you have changed to normal running position
  }
  Serial.println("Write to eeprom.");           //tells you it is saving the end position to the nano memory
  EEPROM.update(0, endPos);                     //this is where it actualy saves the value,in position 0
}

//this is the function that controlls the servo in normal running mode
void running() {
  TrigRead = digitalRead(TrigPin);              //reads the trigger switch
  Serial.print("In Use : ");                    //lets you know the vernier is not in its mount/being used
  Serial.println(TrigRead);                     //prints the value of the triggerto the serial monitor
  if (TrigRead == 1) {                          //if the trigger value is 1 it will do from here {
    for (pos = 120; pos >= endPos; pos -= 1) {            //the servo starts at of 120 degrees and will go through the for statment minusing 1 deg each time round till it reaches the value of the end position (set by the potentiometer)
      myservo.write(pos);                                 //writes the new vallue for each round of the for statment tothe servo
      delay(15);                                          //whates 15milliseconds then starts the for statment again till it is no longer true (pos and endPos are the same)
    }                                                 
    delay(2500);                                          //how long it presses the on/off button on the vernier in milliseconds
    for (pos = endPos; pos <= 120; pos += 1) {            //same as the above for statement but this time it starts at the endPos and adds 1 deg iach time it goes through the statment tillit is at 120 deg
      myservo.write(pos);                                 //
      delay(15);                                          //
    }
    while (TrigRead == 1) {                               //once it has moved the servo it will run this while statemnt till the trig switch  = 1
      TrigRead = digitalRead(TrigPin);                    //reads the trig switch to check it hasnt changed
      mode = digitalRead(modePin);                        //reads the mode pin to check it hasnt changed
      Serial.print("Mounted : ");                         //tells you the vernier is in its holder in the serial monitor
      Serial.println(TrigRead);                           //tells you the value of the trigger switch 
      if (TrigRead == 0 || mode == 1) {                   //if the value of the trig switch = 0 or the mode switch = 1
        break;                                            //it breaks from this if statment and starts from the top of the running loop again
      }
    }
  }                                             //to here }
}