RX-Code

#include <RH_ASK.h>
#include <SPI.h> // Not actualy used but needed to compile

// defines pins numbers
#define trigPin   9
#define echoPin   10
#define buzzer1   11 //change receiver needs Pin 11
#define ledPin    2
#define ldr_pin   7
#define buzzer2   13

long duration;
int distance;
int safetyDistance;
int ldrStatus;
int mss = 0;
uint8_t buf[RH_ASK_MAX_MESSAGE_LEN];
uint8_t buflen = sizeof(buf);

RH_ASK driver;

void setup() {
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input
  pinMode(buzzer1, OUTPUT);
  pinMode(ledPin, OUTPUT);
  pinMode(ldr_pin, INPUT);
  pinMode(buzzer2, OUTPUT);
  if (!driver.init())Serial.println("init failed");
}


void loop() {
  //1: Turn buzzer ON to find device
  //2: Turn buzzer OFF for 5 seconds
  rx433();
  US();
  LDR();
  if (mss == 1) {
    digitalWrite(buzzer1, HIGH);
    digitalWrite(buzzer2, HIGH);
  }
  else if (mss == 2) {
    digitalWrite(buzzer1, LOW);
    digitalWrite(buzzer2, LOW);
    delay(5000);
  }
  if (safetyDistance <= 20)   // You can change safe distance from here changing value Ex. 20 , 40 , 60 , 80 , 100, all in cm
  {
    digitalWrite(buzzer1, HIGH);
    digitalWrite(ledPin, HIGH);
  }
  else if (safetyDistance > 20) {
    digitalWrite(buzzer1, LOW);
    digitalWrite(ledPin, LOW);
  }

  if (ldrStatus == 1) {
    digitalWrite(buzzer2, HIGH);
  }
  else if (ldrStatus == 0) {
    digitalWrite(buzzer2, LOW);
  }

  delay(100);
}


void US() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;
  safetyDistance = distance;
  Serial.print("Distance: ");
  Serial.println(distance);

}

void LDR() {
  ldrStatus = digitalRead(ldr_pin);
  Serial.print("Light: ");
  Serial.println(ldrStatus);
}

void rx433() {
  if (driver.recv(buf, &buflen)) // Non-blocking
  {
    int i;

    // Message with a good checksum received, dump it.
    driver.printBuffer("Got:", buf, buflen);
    mss = atoi(buf);
  }
  Serial.print("mss is set to :");
  Serial.println(mss);
}