void setup() {

  Serial.begin(9600); //Sets up the serial connection to the serial monitor
int ONE = 23;
int TWO = 22;
int THREE = 21;
int FOUR = 20;
pinMode(ONE, OUTPUT); //set pin 23 to OUTPUT
pinMode(TWO, OUTPUT); //set pin 22 to OUTPUT
pinMode(THREE, OUTPUT); //set pin 21 to OUTPUT
pinMode(FOUR, OUTPUT); //set pin 20 to OUTPUT
int FIVE = 11;
int SIX = 10;
int SEVEN = 9;
int EIGHT = 8;
pinMode(FIVE, INPUT); //set pin 11 to INPUT (read mode)
pinMode(SIX, INPUT); //set pin 10 to INPUT (read mode)
pinMode(SEVEN, INPUT); //set pin 9 to INPUT (read mode)
pinMode(EIGHT, INPUT); //set pin 8 to INPUT (read mode)
}
void loop() {
digitalWrite(23,HIGH); //Ties pin 23 high for matrix detection
if (digitalRead(11) == HIGH) {Serial.print("D4  ");} //Prints "D4" to serial monitor
if (digitalRead(10) == HIGH) {Serial.print("C4  ");} //Prints "C4" to serial monitor
if (digitalRead(9) == HIGH) {Serial.print("A4  ");} //Prints "A4" to serial monitor (note pin 9 and 8 are wired backwards woops)
if (digitalRead(8) == HIGH) {Serial.print("B4  ");} //Prints "B4" to serial monitor (note pin 9 and 8 are wired backwards woops)
digitalWrite(23, LOW);
Serial.println();
delay(100);

digitalWrite(22,HIGH); //Ties pin 23 high for matrix detection
if (digitalRead(11) == HIGH) {Serial.print("D3  ");} //Prints "D3" to serial monitor
if (digitalRead(10) == HIGH) {Serial.print("C3  ");} //Prints "C3" to serial monitor
if (digitalRead(9) == HIGH) {Serial.print("A3  ");} //Prints "A3" to serial monitor (note pin 9 and 8 are wired backwards woops)
if (digitalRead(8) == HIGH) {Serial.print("B3  ");} //Prints "B3" to serial monitor (note pin 9 and 8 are wired backwards woops)
digitalWrite(22, LOW);
Serial.println();
delay(100);

digitalWrite(21,HIGH); //Ties pin 23 high for matrix detection
if (digitalRead(11) == HIGH) {Serial.print("D2  ");} //Prints "D4" to serial monitor
if (digitalRead(10) == HIGH) {Serial.print("C2  ");} //Prints "C4" to serial monitor
if (digitalRead(9) == HIGH) {Serial.print("A2  ");} //Prints "A4" to serial monitor (note pin 9 and 8 are wired backwards woops)
if (digitalRead(8) == HIGH) {Serial.print("B2  ");} //Prints "B4" to serial monitor (note pin 9 and 8 are wired backwards woops)
digitalWrite(21, LOW);
Serial.println();
delay(100);

digitalWrite(20,HIGH); //Ties pin 23 high for matrix detection
if (digitalRead(11) == HIGH) {Serial.print("D1  ");} //Prints "D3" to serial monitor
if (digitalRead(10) == HIGH) {Serial.print("C1  ");} //Prints "C3" to serial monitor
if (digitalRead(9) == HIGH) {Serial.print("A1  ");} //Prints "A3" to serial monitor (note pin 9 and 8 are wired backwards woops)
if (digitalRead(8) == HIGH) {Serial.print("B1  ");} //Prints "B3" to serial monitor (note pin 9 and 8 are wired backwards woops)
digitalWrite(20, LOW);
Serial.println();
delay(100);


}