#define ftrig_pin 5
#define fecho_pin 4
#define ltrig_pin 3
#define lecho_pin 2
#define rtrig_pin 6
#define recho_pin 7
#define lmotor 10
#define rmotor 9
void setup()
{
  Serial.begin(9600);
  pinMode(ftrig_pin,OUTPUT);
  pinMode(fecho_pin,INPUT);
    pinMode(ltrig_pin,OUTPUT);
  pinMode(lecho_pin,INPUT);
    pinMode(rtrig_pin,OUTPUT);
  pinMode(recho_pin,INPUT);
}
void loop(){
  analogWrite(lmotor,255);
  analogWrite(rmotor,255);
  digitalWrite(ftrig_pin,HIGH);
  digitalWrite(ltrig_pin,HIGH);
  digitalWrite(rtrig_pin,HIGH);
  delayMicroseconds(10);
  digitalWrite(ftrig_pin,LOW);
  digitalWrite(ltrig_pin,LOW);
  digitalWrite(rtrig_pin,LOW);
  int duration_f,duration_l,duration_r;
  duration_f=pulseIn(fecho_pin,HIGH);
  duration_l=pulseIn(lecho_pin,HIGH);
  duration_r=pulseIn(recho_pin,HIGH);
  Serial.print("forward distance:\n");
  Serial.println(duration_f/58);
    Serial.print("left distance\n");
  Serial.println(duration_l/58);
    Serial.print("right distance:\n");
  Serial.println(duration_r/58);
  if((duration_f/58)<20)
  {
    analogWrite(lmotor,0);
    analogWrite(rmotor,0);
    delay(5000);
  }

  if((duration_l/58)>12 && (duration_r/58)>12)
  {
    analogWrite(lmotor,0);
      analogWrite(rmotor,255);
      delay(10000);
  }
  else if((duration_l/58)>12 && duration_f>30)
  {
    analogWrite(lmotor,125);
    analogWrite(rmotor,255);
    delay(1000);
  }
  else if(duration_r>12 && duration_f>30)
  {
  analogWrite(lmotor,255);
  analogWrite(rmotor,255);
  delay(1000);
  }
  else if(duration_l>12)
  {
    analogWrite(lmotor,125);
    analogWrite(rmotor,255);
    delay(1000);
  }
  else{
        analogWrite(lmotor,255);
    analogWrite(rmotor,125);
    delay(1000);
  }
}