Arduino Variable Gain Amplifier

1void setup() {
2  pinMode(2, OUTPUT);// to pin 1C
3  pinMode(3, OUTPUT);//
4  to pin 2C
5  pinMode(4, OUTPUT);// to pin 3C
6  pinMode(5, OUTPUT);// to pin
7  4C
8  Serial.begin(9600);
9}
10
11char cmd;
12
13void loop() {
14  while
15  (Serial.available() > 0) {
16    cmd = char(Serial.read());
17    
18    if (cmd
19  == '0') {
20      digitalWrite(2, 1);
21      digitalWrite(3, 0);
22      digitalWrite(4,
23  0);
24      digitalWrite(5, 0);
25    }
26    if (cmd == '1') {
27      digitalWrite(2,
28  0);
29      digitalWrite(3, 1);
30      digitalWrite(4, 0);
31      digitalWrite(5,
32  0);
33    }
34    if (cmd == '2') {
35      digitalWrite(2, 0);
36      digitalWrite(3,
37  0);
38      digitalWrite(4, 1);
39      digitalWrite(5, 0);
40    }
41    if
42  (cmd == '3') {
43      digitalWrite(2, 0);
44      digitalWrite(3, 0);
45      digitalWrite(4,
46  0);
47      digitalWrite(5, 1);
48    }
49    if (cmd == '4') {
50      digitalWrite(2,
51  1);
52      digitalWrite(3, 0);
53      digitalWrite(4, 0);
54      digitalWrite(5,
55  1);
56    }
57    if (cmd == '5') {
58      digitalWrite(2, 1);
59      digitalWrite(3,
60  0);
61      digitalWrite(4, 1);
62      digitalWrite(5, 0);
63    }
64    if
65  (cmd == '6') {
66      digitalWrite(2, 1);
67      digitalWrite(3, 1);
68      digitalWrite(4,
69  0);
70      digitalWrite(5, 0);
71    }
72    if (cmd == '7') {
73      digitalWrite(2,
74  0);
75      digitalWrite(3, 1);
76      digitalWrite(4, 0);
77      digitalWrite(5,
78  1);
79    }
80    if (cmd == '8') {
81      digitalWrite(2, 0);
82      digitalWrite(3,
83  1);
84      digitalWrite(4, 1);
85      digitalWrite(5, 0);
86    }
87    if
88  (cmd == '9') {
89      digitalWrite(2, 0);
90      digitalWrite(3, 0);
91      digitalWrite(4,
92  1);
93      digitalWrite(5, 1);
94    }
95  }
96}
97

1void setup() {
2  pinMode(2, OUTPUT);// to pin 1C
3  pinMode(3, OUTPUT);//  to pin 2C
4  pinMode(4, OUTPUT);// to pin 3C
5  pinMode(5, OUTPUT);// to pin  4C
6  Serial.begin(9600);
7}
8
9char cmd;
10
11void loop() {
12  while  (Serial.available() > 0) {
13    cmd = char(Serial.read());
14    
15    if (cmd  == '0') {
16      digitalWrite(2, 1);
17      digitalWrite(3, 0);
18      digitalWrite(4,  0);
19      digitalWrite(5, 0);
20    }
21    if (cmd == '1') {
22      digitalWrite(2,  0);
23      digitalWrite(3, 1);
24      digitalWrite(4, 0);
25      digitalWrite(5,  0);
26    }
27    if (cmd == '2') {
28      digitalWrite(2, 0);
29      digitalWrite(3,  0);
30      digitalWrite(4, 1);
31      digitalWrite(5, 0);
32    }
33    if  (cmd == '3') {
34      digitalWrite(2, 0);
35      digitalWrite(3, 0);
36      digitalWrite(4,  0);
37      digitalWrite(5, 1);
38    }
39    if (cmd == '4') {
40      digitalWrite(2,  1);
41      digitalWrite(3, 0);
42      digitalWrite(4, 0);
43      digitalWrite(5,  1);
44    }
45    if (cmd == '5') {
46      digitalWrite(2, 1);
47      digitalWrite(3,  0);
48      digitalWrite(4, 1);
49      digitalWrite(5, 0);
50    }
51    if  (cmd == '6') {
52      digitalWrite(2, 1);
53      digitalWrite(3, 1);
54      digitalWrite(4,  0);
55      digitalWrite(5, 0);
56    }
57    if (cmd == '7') {
58      digitalWrite(2,  0);
59      digitalWrite(3, 1);
60      digitalWrite(4, 0);
61      digitalWrite(5,  1);
62    }
63    if (cmd == '8') {
64      digitalWrite(2, 0);
65      digitalWrite(3,  1);
66      digitalWrite(4, 1);
67      digitalWrite(5, 0);
68    }
69    if  (cmd == '9') {
70      digitalWrite(2, 0);
71      digitalWrite(3, 0);
72      digitalWrite(4,  1);
73      digitalWrite(5, 1);
74    }
75  }
76}
77