Using Ultrasonic Range Finder SRF02 as Motion Detector

Using Arduino Sensors
3

Hi Tesla!! Thanks again for your answer. You are right, but sometimes is difficult for me to explain everything... I'm using all this sensors to get a better result of motion inside a room... So each sensor will be oriented for a different direction.
If one of this sensors detects motion (PIR) or distance variation (US), it should report me 0. When it detects it should report the value 0 for some seconds.
In other hand when it not detect any movement it returns 1.

The better way is present my entire code (still have a lot of mistakes :blush: )

#include <Wire.h>

const int PIR1 = 2;
const int PIR2 = 3;
const int LED1 = 4;
const int LED2 = 5;


//Definition of variables to use
int val1 = 0;
int val2 = 0;
int count1 = 0;
int count2 = 0;

int calibrationTime = 20;  //calibration time of PIR sensors

void setup()

{
  Wire.begin();          // start the I2C bus

  Serial.begin(9600);    // open the serial port:
  
  //Definition of input/output values
  pinMode(PIR1,INPUT);
  pinMode(PIR2,INPUT);
  pinMode(LED1,OUTPUT);
  pinMode(LED2,OUTPUT);

  
  //give the sensor some time to calibrate
  Serial.println("Sensor Calibration in Progress");
  Serial.println("------------------------------");
  
  for(int i = 0; i < calibrationTime; i++){
    Serial.print(".");
    digitalWrite(LED1, HIGH);
    delay(250);
    digitalWrite(LED2, HIGH);
    delay(250);
    digitalWrite(LED1, LOW);
    delay(250);
    digitalWrite(LED2, LOW);
    delay(250);
  }

  Serial.println("");
  Serial.println("Sensor Calibration Completed");
  Serial.println("Sensor Reading Active");
  delay(100);
}

int reading = 0;
int oldreading = 0;

void loop()

{
passiveIR();
ultrasonic();
presence();

}

void passiveIR()
{
  int val1 = digitalRead(PIR1);
  int val2 = digitalRead(PIR2);

}

void ultrasonic()

{

  // step 1: instruct sensor to read centimeters
  Wire.beginTransmission(112); // transmit to device #112 (0x70)
                               // the address specified in the datasheet is 224 (0xE0)
                               // but i2c adressing uses the high 7 bits so it's 112
  Wire.write(byte(0x00));      // sets register pointer to the command register (0x00)  
  Wire.write(byte(0x51));      // command sensor to measure in "inches" (0x50) 
                               // use 0x51 for centimeters
                               // use 0x52 for ping microseconds
  Wire.endTransmission();      // stop transmitting

  // step 2: wait for readings to happen
  delay(70);                   // datasheet suggests at least 65 milliseconds

  // step 3: instruct sensor to return a particular echo reading
  Wire.beginTransmission(112); // transmit to device #112
  Wire.write(byte(0x02));      // sets register pointer to echo #1 register (0x02)
  Wire.endTransmission();      // stop transmitting

  // step 4: request reading from sensor
  Wire.requestFrom(112, 2);    // request 2 bytes from slave device #112

  // step 5: receive reading from sensor
  if(2 <= Wire.available())    // if two bytes were received
  {
    oldreading = reading;
    //Serial.print(oldreading);    
   // Serial.print(',');
    reading = Wire.read();    // receive high byte (overwrites previous reading)
    reading = reading << 8;   // shift high byte to be high 8 bits
    reading |= Wire.read();   // receive low byte as lower 8 bits
    //Serial.println(reading);    // print the reading
   // Serial.print(',');

  }

  delay(250);                 // wait before next reading:

}

void presence()
{
  int f = reading - oldreading;
  
  if(val1 == HIGH || val2 == HIGH || f >15){
    Serial.print('0');
    Serial.print(',');
  }
    
  if(val1 == LOW || val2 == LOW || f < 15){
    Serial.print('1');
    Serial.print(',');
   
   for(int i=0; i<50; i++){
   }  
  }
}

I hope you can reach my goal, if can try to explain better.

Obrigado :wink: