1- There is a PIR sensor at the entrance and exit gate ,if a car approaches it, it will sense the infrared signal radiation, Signal is sent to the microcontroller that has a car at the entrance gate, then the microcontroller checks the number of cars inside the garage (because the garage capacity is only 3 cars) If an empty space is found, it will send a signal to servo motor rotates by +90 ° and raise it ,the metal barrier that closed the road it does the 2sec Delay until the car gets in completely and turns back at an angle of -90 ° and closes The way and all the cases are printed on the lcd and the number of cars inside the garage and whether entry is available or not By the number of cars inside.

2- In case there is no car The entry or exit area of ​​the sensor has a low signal for the microcontroller,so there are no cars ,then will be printed "car number inside equal ... " ,also, permissibility of entry is printed if the number of cars inside is less than 3, but if the number inside is 3 cars, then it is printed "It is not allowed to enter the garage is full " " Max number of car is only three cars " .

3-In the case of exit, if a car approaches the exit gate The same cycle will occur in one step, the sensor will have a High signal for the microcontroller that there is a car at the exit gate, it will be displayed on the LCD that "There is a car at the exit gate" Then the servo motor rotates at an angle of + 90 ° in order to raise the metal barrier and open the way Delay by 2sec until the car comes out, and then the servo rotates at -90 ° so that the metal barrier descends and closes the road, and the lcd displays the new number of cars inside the garage, the permissibility of entry or nothing, and so on..

• 1- PIR Passive infrared sensor 📼

• 2- LCD LM32 🖥️

• 3- Servo motor

• 4- logic state

• 5- Led 💡