// MCU BASIC: https://www.basic4mcu.com
// DateTime : 2018-06-02 오후 10:18:56
// by Ok-Hyun Park
//
#include <SoftwareSerial.h>
SoftwareSerial BTSerial(4,5);
//
int relay1=9,relay2=10;
int trig=2,echo=3;
//
int cnt=0,inData;
unsigned long duration;
float distance;
//
void setup(){
  pinMode(relay1,OUTPUT); pinMode(relay2,OUTPUT);
  pinMode(trig,OUTPUT); pinMode(echo,INPUT);
  pinMode(8,OUTPUT);
  BTSerial.begin(9600);
}
//
void loop(){
  if(BTSerial.available()){
    inData=BTSerial.read();
    if(inData=='a'){ DOWN(); cnt=0; } //4초간 역방향으로 작동
  }
  //
  digitalWrite(trig,HIGH); delayMicroseconds(10); digitalWrite(trig,LOW);
  duration=pulseIn(echo,HIGH); distance=duration /58;
  //
  if(inData=='a'){
    if(distance>15){
      if(++cnt==100){ // 100초 동안 물체가 감지되지 않았다면 // 10초=100ms*100
        digitalWrite(relay2,HIGH); delay(4000); digitalWrite(relay2,LOW); // 4초 정방향
        inData=0; cnt=0;
      }
    }
    else{ // 15cm 이내에 물체가 감지되면
      cnt=0; inData=0;
    }
  }
  //
  delay(100); //100ms
}
//
void DOWN(){
  digitalWrite(relay1,HIGH); delay(4000); digitalWrite(relay1,LOW);
}