Arduinoを使ったセブンセグメントLEDディスプレイの使い方

/*
 *  Robojax Arduino Step-by-Step Course
 * Lesson 21: Seven-Segment Display
 * Display number on seven-segment display with Arduino

   Please watch video instruction here: https://youtu.be/pxUjEsJQW2M
   or watch this https://youtu.be/f3GqRMQ8jYs

 * Written by Ahmad Shamshiri for Robojax (Robojax.com)
 * on December 07, 2018 at 22:34 in Ajax, Ontario, Canada

 * 
  * This code is "AS IS" without warranty or liability. Free to be used as long as you keep this note intact.
 * This code has been downloaded from Robojax.com
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */


#define type 1 // 0 for common cathode and 1 for common anode

const int displayPins[7] = {2,3,4,5,6,7,8}; // define pins
const int dicimalPoint = 9;// decimal point

// array for seven-segment LED values. Do not change. 
//This is used for both common anode and common cathode
byte displayLEDs[10][7] = { 
        { 0,0,0,0,0,0,1 },  // = 0
        { 1,0,0,1,1,1,1 },  // = 1
        { 0,0,1,0,0,1,0 },  // = 2
        { 0,0,0,0,1,1,0 },  // = 3
        { 1,0,0,1,1,0,0 },  // = 4
        { 0,1,0,0,1,0,0 },  // = 5
        { 0,1,0,0,0,0,0 },  // = 6
        { 0,0,0,1,1,1,1 },  // = 7
        { 0,0,0,0,0,0,0 },  // = 8
        { 0,0,0,0,1,0,0 }   // = 9     
        }; 
/*
 * 
 * @brief Writes digit to display 
 * @param digit (integer)
 * @return no return value
 * Written by Ahmad Shamshiri on Friday, December 7, 2018 for Robojax.com
 */        
void writeDigit(int digit) {
  // Robojax Seven-Segment Display for Arduino
  Serial.print(digit);
  Serial.print(" ");

   int digitValue;
  for (int i=0; i < 7; i++) 
  {

      digitalWrite(displayPins[i], convertHighLow(displayLEDs[digit][i]));// write the HIGH or LOW (depending on the type) to output pin
      Serial.print(convertHighLow(displayLEDs[digit][i]));// print the result to the Serial monitor

  }// for i
}//writeDigit ends here

/*
 * 
 * @brief Converts HIGH and LOW based on the "type" variable value
 * if type is 1, converts the "V" to LOW, or returns it as it is if type is 0 (zero)
 * @param v (integer)
 * @return the convertedValue
 * Written by Ahmad Shamshiri (Robojax.com) on Friday, December 8, 2018 for Robojax.com
 */  
int convertHighLow(int v)
{
  int convertedValue;
    if(type ==0)
    {
      convertedValue = 1 - v;// if common anode, change the HIGH to LOW and LOW to HIGH
    }else{
      convertedValue = v;// if common cathode, keep it the same
    } 

    return convertedValue;
}

void setup() {
  // Robojax Seven-Segment Display for Arduino
//Robojax Arduino Step-by-Step Course http://robojax.com/L/?id=338  
  for(int d=0; d<8; d++)
  {
    pinMode(displayPins[d], OUTPUT);// set pin as output
    
  }
   pinMode(dicimalPoint,OUTPUT);// define a pin for decimal point
   digitalWrite(dicimalPoint,HIGH);// turn decimal point OFF. Set to LOW if common Anode and HIGH for common cathode

  Serial.begin(9600);// initialize serial monitor with 9600 baud
}// setup ends here


void loop() {
  // Robojax Seven-Segment Display for Arduino
//Robojax Arduino Step-by-Step Course http://robojax.com/L/?id=338  
 for (int i=0; i<=9 ; i++) {
   writeDigit(i); 
   Serial.println("=====");
   delay(1000);
  }
  digitalWrite(dicimalPoint,LOW);// turn decimal point ON
  delay(3000);
 // writeDigit(4);
  // delay(3000);

}// loop ends here