The prototype of the parking system consist of four HC-SR04 ultrasonic sensors, two Arduino Mega, and an ESP-8266 Wi-Fi module as part of hardware components. For the software parts, Google Sheets acts as a simplified database, and Google HTML Service web page were used to display the availability of parking spaces in real-time.
This system make use of HTTPS Redirect library from electronicsguy. The files used and modified in this system are GoogleDocs.ino and GoogleScript.gs. The original files are located in the HTTPSRedirect directory.
This system was developed on July 2018.
This system makes up of three main parts; the Input & Processing Unit, the Communication Unit, and the Output & Database.
Each parking space consist of one HC-SR04 ultrasonic sensor which acts as an input to determine whether the parking space is vacant or occupied. The sensor operates at 40 kHz, 5V, and 15mA of current. Also, the range of the detectable distance from the sensor is between 2cm to 4m.
Each sensor is connected to an Arduino Mega microcontroller board which acts as a processing unit for the system. The board can be powered by either an external AC-to-DC adapter or by an USB cable type A/B to provide a constant power supply to the system.
There are many methods of communication available in order to make the system to be able to communicate with the Google Sheets via Internet. In this system, the methods of communication used is ESP8266 ESP-01 Wi-Fi module. The module provides the capability to wirelessly connect to a Wi-Fi network to transmit and receive data. It uses 2.4 Hz Wi-Fi (802.11 b/g/n) specification that supporting WPA/WPA2. As the module itself is a microcontroller chip, it needs to be programmed first in order to use it.
The data from sensors are stored in the Google Sheets which acts a simplified database. Google Sheets can be scripted using Google Apps Script to create and modify spreadsheets. Google Apps Script is a JavaScript cloud scripting language that is executed on Google Cloud.
In the system, Google Sheets is used to store and keep track of the data regarding the parking availability. To display the data in a more user-friendly format, the Google HTML Service is used to create user interface in the form of web pages. Hence, Google Apps Script acts as a link between ESP8266 Wi-Fi module & Google Sheets, and also between Google Sheets & the web page.
This how the output on the Google Sheets will looks like:
And this is how the output display in the web page.
