PWM for led control. With pot and buttons to adjust brightness

PWM.ino

// All the pins needed
int pin_led = 9;
int pin_pot = 0;
int pin_button_mode = 2;
int pin_button_up = 3;
int pin_button_down = 4;

// Button state. 0 = button off , 1 = button pressed in
bool button_mode_state = 1;
bool button_up_state = 1;
bool button_down_state = 1;

// Store the current led brightness
int led_brightness_current = 0;

// Store both the pot and button brightness
int led_brightness_pot = 0;

int led_brightness_buttons = 0;
int led_button_change_size = 5; // Increase/decrease brightness by this amount

int mode = 0;

String serialReceiveData;

void read_pot_value()
{
  led_brightness_pot = analogRead(pin_pot);
  led_brightness_pot = (led_brightness_pot/4.2+10); // scale and shift the led_brightness_pot to be a useful
}

void read_button_states()
{
  if(button_mode_state != digitalRead(pin_button_mode)){
    button_mode_state != button_mode_state; // Invert old state
    
    // Set Mode on button release
    if(button_mode_state == 1)
    {
      mode++; // Increment
      if(mode > 0 )
      {
        Serial.println("Mode : On");
      }      
    }
    // Loop through modes
    if(mode > 1)
    {
      mode = 0;
      Serial.println("Mode : Off");
    }

    delay(200);
  }

  if(button_up_state != digitalRead(pin_button_up) && mode != 0 ){
    button_up_state != button_up_state;
    // Increase Brightness
    if(button_up_state == 1)
    {
      led_brightness_buttons += led_button_change_size;
    }
    if(led_brightness_buttons > 255)
    {
      led_brightness_buttons = 255;
    }
  }

  if(button_down_state != digitalRead(pin_button_down) && mode != 0){
    button_down_state != button_down_state;
    // Decrease Brightness
    if(button_down_state == 1)
    {
      led_brightness_buttons -= led_button_change_size;
    }
    if(led_brightness_buttons < 0)
    {
      led_brightness_buttons = 0;
    }
  }
}

void set_led_brightness(int brightness)
{
  // Validate
  if(brightness > 255)
  {
    brightness = 255;
  }
  if(brightness < 0)
  {
    brightness = 0;
  }
  if(led_brightness_current != brightness)
  {
    led_brightness_current = brightness;
    analogWrite(pin_led,brightness);
    Serial.print("Mode:");
    Serial.print(mode);
    Serial.print("Brightness:");
    Serial.println(brightness);
    delay(50);

  }
}

bool read_serial()
{
  bool result = false;
  while (Serial.available() > 0)
  {
    char received = Serial.read();
    if(isDigit(received)){
      serialReceiveData += received;
    }
    // Process message when new line character is recieved
    if (received == '\n')
    {
      set_led_brightness(serialReceiveData.toInt());
      result =true;
      mode = -1;
      serialReceiveData = ""; // Clear recieved buffer
    }
  }
  return result;
}

void setup()
{
  // Set pin modes
  pinMode(pin_led, OUTPUT);
  pinMode(pin_button_mode, INPUT);
  pinMode(pin_button_up, INPUT);
  pinMode(pin_button_down, INPUT);
  // start serial
  Serial.begin(9600);
  Serial.println("Starting Up...");
}

void loop()
{
  if(!read_serial())  // If not set by serial command check hardware input
  {
    read_button_states();
    read_pot_value();

    // off mode
    if(mode == 0)
    {
      set_led_brightness(0);
    }    

    // button mode
    if(mode == 1)
    {
      set_led_brightness(led_brightness_buttons);
    }
  }       
}