 const unsigned short DEBUG = OFF; //debug information on Serial
 boolean bootError = false;
 const unsigned short MAX_VALIDATION_EFFORTS = 5; //max amount of efforts to try and reconnect to the network if you have failed in setup()
+
+/* Sonar (presence detection) declarations */
+Sonar sonar;
+const unsigned short TRIG_PIN = A2; //ultrasonic sensor's trigger pin
+const unsigned short ECHO_PIN = A1; //ultrasonic sensor's echo pin
+const unsigned short US_VCC = A3; //the pin that will provide the voltage to the ultrasonic sensor
+const unsigned short US_GROUND = A0; //pin that will provide ground to the ultrasonic sensor
+unsigned long lastMeasurement = 0;
+const unsigned short US_INTERVAL = 100; //frequency in milliseconds of measurements by the ultrasonic sensor
 
 void setup() {
   keyboard.begin(DataPin, IRQpin);

      lcd.print("Check WiFi");
    }
  }
  lastKeyStroke = millis(); //start considering keystrokes as soon as setup() is finished
}

void loop() {

#include <PS2Keyboard.h>
#include <SoftwareSerial.h>
#include "Vars.h"
#include <Smartcar_sensors.h>

/* LCD screen declarations */
#define I2C_ADDR 0x3F // I2C address for the green 16x2 LCD screen (0x27 is the address of the blue i2c screen)
