Wheeled Self-Balancing Robot | Arduino L293D & HC SR-04

1int ip3=2,ip4=3;
2int t=8,e=9;
3
4
5void setup() {
6  pinMode(t,  OUTPUT);  //trigger pin
7  pinMode(e, INPUT);  //echo pin
8  
9  pinMode(ip3,OUTPUT);
10  pinMode(ip4,OUTPUT);
11
12
13}
14
15
16float distance(){
17  
18  float  duration, cm;
19  
20  digitalWrite(t, LOW);
21  delayMicroseconds(2);
22  digitalWrite(t,  HIGH);
23  delayMicroseconds(5);
24  digitalWrite(t, LOW);
25  
26  duration  = pulseIn(e, HIGH);
27
28
29  cm = duration/ 29 / 2;
30  
31  return cm; //returns  distance in centimeters
32}
33
34
35void loop() {
36  
37  float dis = distance();
38
39
40  if (dis>27){
41    digitalWrite(ip3,LOW);
42    digitalWrite(ip4,HIGH);
43  
44  }else if(dis<27){
45    digitalWrite(ip3,HIGH);
46    digitalWrite(ip4,LOW);
47  }
48
49
50}
51