Abstract—The purpose of this research is to design a Parking
Guidance System (PGS) for UBINUS Anggrek Campus’ parking
building by using Real Time Operating System (RTOS), PIC32,
Communication Protocol RS485, and ultrasonic sensor. The
system design consists of several main parts, which are Master
Controller (PC) as the main system controller, Sensor Controller
as the controller for three ultrasonic sensors, and also RS485-toRS232
Converter as the data communication converter from
Sensor Controller to Master Controller (PC), vice versa. The
experiments that will be done consists several things, such as
measuring and researching UBINUS Anggrek Campus’ parking
building, measuring the range that can be measured by sensor,
determining the safest distance for sensors to avoid interference,
and also measuring the time needed for Master Controller (PC)
to update data from Sensor Controllers. The result shows that
this system can be implemented well in UBINUS Anggrek
Campus’ parking building without worrying any interference
that might occur and sensor can measure well in a distance of 10
– 280 cm. Implementing RTOS into PGS can update data from
each Sensor Controller with the average time of 1045 ms from
the scale of 133 – 2600 ms. In our system one PIC32
microcontroller can handle up to three ultrasonic sensors reliably
because of using RTOS task scheduling