// declare integer variables 
 int 
PIR = 
 0 
 ; 
 int 
temp = 
 0 
 ; 
 int 
IR = 
 0 
 ; 
 int 
gas = 
 0 
 ; 
 void 
 setup 
 ( 
 ) 
 { 
 // declare inputs 
 pinMode 
 ( 
 6 
 , 
INPUT ) 
 ; 
 pinMode 
 ( 
 7 
 , 
INPUT ) 
 ; 
 pinMode 
 ( 
 5 
 , 
INPUT ) 
 ; 
 pinMode 
 ( 
 4 
 , 
INPUT ) 
 ; 
 // declare outputs 
 pinMode 
 ( 
 13 
 , 
OUTPUT ) 
 ; 
 pinMode 
 ( 
 12 
 , 
OUTPUT ) 
 ; 
 pinMode 
 ( 
 11 
 , 
OUTPUT ) 
 ; 
 pinMode 
 ( 
 10 
 , 
OUTPUT ) 
 ; 
 // begin the serial port with a baud rate of 9600 
Serial . 
 begin 
 ( 
 9600 
 ) 
 ; 
 } 
 void 
 loop 
 ( 
 ) 
 { 
 // declare variables 
PIR = 
 digitalRead 
 ( 
 4 
 ) 
 ; 
temp = 
 analogRead 
 ( 
 5 
 ) 
 ; 
IR = 
 digitalRead 
 ( 
 7 
 ) 
 ; 
gas = 
 analogRead 
 ( 
 6 
 ) 
 ; 
 // if else statements 
 if 
 ( 
temp >= 
 500 
 ) 
 { 
 digitalWrite 
 ( 
 12 
 , 
HIGH ) 
 ; 
Serial . 
 println 
 ( 
 "fan on" 
 ) 
 ; 
 } 
 else 
 { 
 digitalWrite 
 ( 
 12 
 , 
LOW ) 
 ; 
Serial . 
 println 
 ( 
 "fan off" 
 ) 
 ; 
 } 
 if 
 ( 
PIR == 
 1 
 ) 
 { 
 digitalWrite 
 ( 
 13 
 , 
HIGH ) 
 ; 
Serial . 
 println 
 ( 
 "lights on" 
 ) 
 ; 
 } 
 else 
 { 
 digitalWrite 
 ( 
 13 
 , 
LOW ) 
 ; 
Serial . 
 println 
 ( 
 "lights off" 
 ) 
 ; 
 } 
 if 
 ( 
gas >= 
 200 
 ) 
 { 
 digitalWrite 
 ( 
 10 
 , 
HIGH ) 
 ; 
Serial . 
 println 
 ( 
 "gas leak" 
 ) 
 ; 
 } 
 else 
 { 
 digitalWrite 
 ( 
 10 
 , 
LOW ) 
 ; 
 } 
 if 
 ( 
IR == 
 1 
 ) 
 { 
 digitalWrite 
 ( 
 11 
 , 
HIGH ) 
 ; 
Serial . 
 print 
 ( 
 "signal received" 
 ) 
 ; 
 } 
 else 
 { 
 digitalWrite 
 ( 
 11 
 , 
LOW ) 
 ; 
 } 
 delay 
 ( 
 30 
 ) 
 ; 
 // delay 30 milliseconds to let things settle 
 }