#include <SoftwareSerial.h>

#define ADDetector 5
#define rxPin 3
#define txPin 4
#define LEDC 7
#define LEDA 8

SoftwareSerial mySerial(rxPin,txPin);

void setup() {
  Serial.begin(9600);
  pinMode(rxPin,INPUT);
  pinMode(txPin,OUTPUT);
  pinMode(LEDC,OUTPUT);
  pinMode(LEDA,OUTPUT);
  digitalWrite(LEDC,LOW);
  digitalWrite(LEDA,LOW);
  mySerial.begin(2400);
}

long minDetectorNoise() {
  long val=analogRead(ADDetector);
  for (int i=0;i<500;i++) {
    long tmp=analogRead(ADDetector);
    if (tmp<val) val=tmp;
  }
  return val;
}

void loop() {
  long start;
  long dist[3]; // in roughly tenths of a foot
  boolean any=false;

  for (int i=0;i<3;i++) {
    long ADMin=(minDetectorNoise()*95)/100; // Below 95 percent of min of 500 samples is a signal
    dist[i]=0;
    mySerial.print((char)0xff);
    mySerial.print((char)0x00);
    mySerial.print((char)0x5a);
    mySerial.print((char)i);
    start=millis();
//    delayMicroseconds(400);  // let detector settle from radio noise
    do {
      dist[i]++;
    }while (dist[i]<1000 && analogRead(ADDetector)>ADMin);
    if (dist[i]<1000) {
      delay(100-dist[i]/10);
      any=true;
    }
  }
  if (any) digitalWrite(LEDA,HIGH);
  else     digitalWrite(LEDA,LOW);
  for(int i=0;i<3;i++) {
    Serial.print(i);
    Serial.print("|");
    Serial.print(dist[i]/10);
    Serial.print('.');
    Serial.print(dist[i]%10);
    Serial.print('|');
  }
  Serial.println();
}