AVR based parking system - Simple Arduino Based Automated Parking Lot System - page 9

Figure 1.6: A flowchart of the AVR program
In the beginning of the program, needed libraries, suitable symbols for each microcon-
troller pins and then needed variables are defined. Then the program goes into the main
function and does the following work for one time:
1. It gets the current time and date from RTC ( A Real Time Clock is connected to AVR
)
2. The zero (0) number is stored as initial content of all variables related to the entrance
and exit time of each parking slot.
3. It computes the total number of vacancies in the parking lot
Then the program calls several functions, each one performing a specific task, such as dis-
playing data on the LCD, computing the number of available cars, controlling the LEDs
etc. The important functions are explained in following sections.