Simple Bluetooth Car with Android App

1/*
2 * Control 4 DC motors with Smartphone via bluetooth
3 */
4  
5int motor1Pin1 = 4;
6int motor1Pin2 = 5; 
7int enable1Pin = 3; 
8int motor2Pin1  = 12; 
9int motor2Pin2 = 13;
10int enable2Pin = 11; 
11int state;
12int flag=0;        
13int stateStop=0;
14void setup() {
15    // sets the pins as outputs:
16    pinMode(motor1Pin1, OUTPUT);
17    pinMode(motor1Pin2, OUTPUT);
18    pinMode(enable1Pin,  OUTPUT);
19    pinMode(motor2Pin1, OUTPUT);
20    pinMode(motor2Pin2, OUTPUT);
21    pinMode(enable2Pin, OUTPUT);
22    // sets enable1Pin and enable2Pin high so  that motor can turn on:
23    digitalWrite(enable1Pin, HIGH);
24    digitalWrite(enable2Pin,  HIGH);
25    // initialize serial communication at 9600 bits per second:
26    Serial.begin(9600);
27}
28
29void  loop() {
30    if(Serial.available() > 0){     
31      state = Serial.read();   
32      flag=0;
33    }   
34    // if the state is 'F' the DC motor will  go forward
35    if (state == 'F') {
36        digitalWrite(motor1Pin1, HIGH);
37        digitalWrite(motor1Pin2, LOW); 
38        digitalWrite(motor2Pin1, LOW);
39        digitalWrite(motor2Pin2, HIGH);
40        if(flag == 0){
41          Serial.println("Go  Forward!");
42          flag=1;
43        }
44    }
45    
46    // if the  state is 'R' the motor will turn left
47    else if (state == 'R') {
48        digitalWrite(motor1Pin1,  HIGH); 
49        digitalWrite(motor1Pin2, LOW); 
50        digitalWrite(motor2Pin1,  LOW);
51        digitalWrite(motor2Pin2, LOW);
52        if(flag == 0){
53          Serial.println("Turn  LEFT");
54          flag=1;
55        }
56        delay(1000);
57        state=3;
58        stateStop=1;
59    }
60    // if the state is 'S' the motor will Stop
61    else if (state == 'S' || stateStop == 1) {
62        digitalWrite(motor1Pin1,  LOW); 
63        digitalWrite(motor1Pin2, LOW); 
64        digitalWrite(motor2Pin1,  LOW);
65        digitalWrite(motor2Pin2, LOW);
66        if(flag == 0){
67          Serial.println("STOP!");
68          flag=1;
69        }
70        stateStop=0;
71    }
72    // if the  state is 'L' the motor will turn right
73    else if (state == 'L') {
74        digitalWrite(motor1Pin1,  LOW); 
75        digitalWrite(motor1Pin2, LOW); 
76        digitalWrite(motor2Pin1,  LOW);
77        digitalWrite(motor2Pin2, HIGH);
78        if(flag == 0){
79          Serial.println("Turn  RIGHT");
80          flag=1;
81        }
82        delay(1000);
83        state=3;
84        stateStop=1;
85    }
86    // if the state is 'B' the motor will Reverse
87    else if (state == 'B') {
88        digitalWrite(motor1Pin1, LOW); 
89        digitalWrite(motor1Pin2,  HIGH);
90        digitalWrite(motor2Pin1, HIGH);
91        digitalWrite(motor2Pin2,  LOW);
92        if(flag == 0){
93          Serial.println("Reverse!");
94          flag=1;
95        }
96    }
97    //For debugging purpose
98    Serial.println(state);
99}