1. //L293D
2. //Motor A
3. const int motorPin1  = 5;  // Pin 14 of L293
4. const int motorPin2  = 6;  // Pin 10 of L293
5. //Motor B
6. const int motorPin3  = 10; // Pin  7 of L293
7. const int motorPin4  = 9;  // Pin  2 of L293
8.  
9. #define TIME_WAIT 15000
10.  
11. void setup() {
12.   //Set pins as outputs
13.   pinMode(motorPin1, OUTPUT);
14.   pinMode(motorPin2, OUTPUT);
15.   pinMode(motorPin3, OUTPUT);
16.   pinMode(motorPin4, OUTPUT);
17. }
18.  
19. void left_stop() {
20.   digitalWrite(motorPin1, LOW);
21.   digitalWrite(motorPin2, LOW);
22. }
23.  
24. void right_stop() {
25.   digitalWrite(motorPin1, LOW);
26.   digitalWrite(motorPin2, LOW);
27. }
28.  
29.  
30. void stop() {
31.   left_stop();
32.   right_stop();
33. }
34.  
35. void left_forward() {
36.   digitalWrite(motorPin1, LOW);
37.   digitalWrite(motorPin2, HIGH);
38. }
39.  
40. void left_backward() {
41.   digitalWrite(motorPin1, HIGH);
42.   digitalWrite(motorPin2, LOW);
43. }
44.  
45. void right_forward() {
46.   digitalWrite(motorPin3, LOW);
47.   digitalWrite(motorPin4, HIGH);
48. }
49.  
50. void right_backward() {
51.   digitalWrite(motorPin3, HIGH);
52.   digitalWrite(motorPin4, LOW);
53. }
54.  
55. void forward() {
56.   left_forward();
57.   right_forward();
58. }
59.  
60. void backward() {
61.   left_backward();
62.   right_backward();
63. }
64.  
65. void left_rotate() {
66.   left_backward();
67.   right_forward();
68. }
69.  
70. void right_rotate() {
71.   left_forward();
72.   right_backward();
73. }
74.  
75. void left_circle() {
76.   left_stop();
77.   right_forward();
78. }
79.  
80. void right_circle() {
81.   right_stop();
82.   left_forward();
83. }
84.  
85. void wait() {
86.   delay(TIME_WAIT);
87.   stop();
88. }
89.  
90. void loop() {
91.   forward();
92.   wait();
93.   backward();
94.   wait();
95.   left_rotate();
96.   wait();
97.   right_rotate();
98.   wait();
99.   left_circle();
100.   wait();
101.   right_circle();
102.   wait();
103.   stop();
104.   delay(2000);
105. }