Displaying Key Pressed on Serial Monitor

1//Read input from keypad and write key pressed to serial terminal
2
3//variable  declarations
4int button1 = 0;
5int button2 = 0;
6int button3 = 0;
7int  buttonA = 0;
8int button4 = 0;
9int button5 = 0;
10int button6 = 0;
11int  buttonB = 0;
12int button7 = 0;
13int button8 = 0;
14int button9 = 0;
15int  buttonC = 0;
16int buttonAst = 0;
17int button0 = 0;
18int buttonHash = 0;
19int  buttonD = 0;
20
21char ast = '*';
22char hash = '#';
23char Alfa = 'A';
24char  Bravo = 'B';
25char Charlie = 'C';
26char Delta = 'D';
27
28void setup() {
29  // put your setup code here, to run once:
30  Serial.begin(9600);   //configure  serial port to 9600 baud
31  
32  //set pins 2-5 as output
33  for (int i = 2;  i < 6; i++){
34    pinMode(i, OUTPUT);
35  }
36  
37  //set pins 6-9 as input
38  for (int i = 6; i < 10; i++){
39    pinMode(i, INPUT);
40  }
41}
42
43void  loop() {
44  // put your main code here, to run repeatedly:
45  
46  digitalWrite(2,  HIGH);   //set pin 0 high
47  //check if input pins go high (button pressed)
48  button1 = digitalRead(6);
49  button4 = digitalRead(7);
50  button7 = digitalRead(8);
51  buttonAst = digitalRead(9);
52  digitalWrite(2, LOW);    //set pin 0 low
53  
54  if(button1 == 1){
55    delay(150);   //wait until switch settles
56    
57    Serial.println(1);
58  }
59
60  if(button4 == 1){
61    delay(150);   //wait  until switch settles
62
63    Serial.println(4);
64  }
65
66  if(button7 ==  1){
67    delay(150);   //wait until switch settles
68
69    Serial.println(7);
70  }
71
72  if(buttonAst == 1){
73    delay(150);   //wait until switch settles
74
75    Serial.println(ast);
76  }
77
78  digitalWrite(3, HIGH);   //set pin 0 high
79  //check if input pins go high (button pressed)
80  button2 = digitalRead(6);
81  button5 = digitalRead(7);
82  button8 = digitalRead(8);
83  button0 = digitalRead(9);
84  digitalWrite(3, LOW);    //set pin 0 low
85  
86  if(button2 == 1){
87    delay(150);   //wait until switch settles
88    
89    Serial.println(2);
90  }
91
92  if(button5 == 1){
93    delay(150);   //wait until switch settles
94
95    Serial.println(5);
96  }
97
98  if(button8 == 1){
99    delay(150);   //wait until switch settles
100
101    Serial.println(8);
102  }
103
104  if(button0 == 1){
105    delay(150);   //wait  until switch settles
106
107    Serial.println(0);
108  }
109
110  digitalWrite(4,  HIGH);   //set pin 0 high
111  //check if input pins go high (button pressed)
112  button3 = digitalRead(6);
113  button6 = digitalRead(7);
114  button9 = digitalRead(8);
115  buttonHash = digitalRead(9);
116  digitalWrite(4, LOW);    //set pin 0 low
117  
118  if(button3 == 1){
119    delay(150);   //wait until switch settles
120    
121    Serial.println(3);
122  }
123
124  if(button6 == 1){
125    delay(150);   //wait  until switch settles
126
127    Serial.println(6);
128  }
129
130  if(button9 ==  1){
131    delay(150);   //wait until switch settles
132
133    Serial.println(9);
134  }
135
136  if(buttonHash == 1){
137    delay(150);   //wait until switch settles
138
139    Serial.println(hash);
140  }
141
142   digitalWrite(5, HIGH);   //set pin 0  high
143  //check if input pins go high (button pressed)
144  buttonA = digitalRead(6);
145  buttonB = digitalRead(7);
146  buttonC = digitalRead(8);
147  buttonD = digitalRead(9);
148  digitalWrite(5, LOW);    //set pin 0 low
149  
150  if(buttonA == 1){
151    delay(150);   //wait until switch settles
152    
153    Serial.println(Alfa);
154  }
155
156  if(buttonB == 1){
157    delay(150);   //wait until switch settles
158
159    Serial.println(Bravo);
160  }
161
162  if(buttonC == 1){
163    delay(150);   //wait until switch settles
164
165    Serial.println(Charlie);
166  }
167
168  if(buttonD == 1){
169    delay(150);   //wait until switch settles
170
171    Serial.println(Delta);
172  }
173}
174