The Solver team SK8 consists of 8 students of the Faculty of Informatics and Information Technologies in Slovak Technical University in Bratislava who decided to deal with a currently rapidly developing topic of smart cities and IoT, smart parking. The project was developed in cooperation with external companies Unicorn Systems SK and Orange SK, so students had a chance to gain experience from IT industry. We asked team members after their presentation in the First Demo Day in Pula (see pictures below) on 28 June 2018 several questions.

Q: The concept of smart city includes many areas. What inspired you to choose smart parking?
A: We study in Bratislava, where we see traffic jams and nervous driver on daily basis. This experience and study data confirm that most of the traffic jams are caused by drivers looking for a place to park. This has led us to the opinion, that after finishing this project, it will be actually deployable and it won’t be just a prototype to be abandoned like most of the school projects. Also, we were impressed by new IoT technologies, with which we haven’t had a chance to get acquainted with yet. Last but not least, we were in favour of the project by our STU and Unicorn co-mentors having with good reputation and experience in the field.
 

Q: Could you introduce the infrastructure of IoT devices you used?
A: Sensors we use were developed in parallel with our project by the affiliated STU faculty – Faculty of Electrical Engineering and IT (FEI) in a team project as well. The sensors are capsule shaped devices 15 cm long and 5 cm in diameter, their life expectancy is 7 years. They are embedded in the surface of  the parking spot and can evaluate whether a car has parked or just left based on the changes in electromagnetic field. Then they send a short message about the change in occupancy along with other data, such as battery status, signal strength or temperature. These messages are then stored into MQTT (Message Queuing Telemetry Transport), which our server is subscribed to. Finally, server processes these messages and updates status in a database.

Q: There are already similar solutions using cameras or ceiling sensors. Why did the  new technology arise? And why haven’t you used the sensors just mentioned?
A: Camera systems are a good option for wide, big parking lots with no obstacles or say, squared shaped parking lots (so one camera can monitor a wide area). Ceiling sensors are a good option in garages. But in fact, there aren’t only such parking lots, and if you want to monitor for example a long street with trees and other obstacles, camera solutions are getting expensive. Also in comparison with other sensor solutions, sensors we use are wireless and significantly smaller, so their installation is easier. You just need to drill just a small hole, put sensor inside and that’s it, sensor is almost ready for operation.
 

Q: You have just mentioned: ”life expectancy of a sensor is 7 years”, is it really better than wired solutions?
A: We assume so, because installation of one sensor takes only a few minutes. In MQTT, the  messages we receive include also battery status, so we can react on some sudden changes.
 And also in 7 years, we expect battery technologies to be better than nowadays.
 

Q: How will people use the processed data sent by sensors?
A: We developed a web application, which allows users to search and visualize current state of parking lots on a map. In current view of parking lot, users can see which spot is empty and which is not along with other data about parking lot and parking spots, such as price list or average parking lot occupance in week.
 

Q: Why have you decided to develop a web application rather than a mobile application?
A: For MVP, we chose web app mainly due to time constraints, because this was a school project and basically, developing 2 applications (web + mobile) could have been backfiring. In addition, today´s web applications offer high responsive potential, so despite the fact, that 90 % of expected users may use mobile devices, we opted for the responsive web. However, it is not the full answer to this question, we came across a number of issues with mobile option. These problems are currently being solved by redesigning of application. We have  also received a request from the customer to develop a mobile application, so the mobile version is highly likely to be created too.

Q: Does your application also allow users to view statistical data about parking?
A: Yes, but these functions are only accessible to the city and parking providers. After logging in as a parking provider, the user simply switches the view from the current to the historical one and application displays various parking statistics covering the last three months. So far, we keep only last three months mostly because of storage reasons, There  wasn’t any requirement for storing these data for a longer period. In history view, it is also possible to visualize different charts and heat maps about parking lot occupancy, e.g. a statistics on weekly of occupation of parking lots for drivers.
 

Q: Does this mean that users can sign in in different roles?
A: Yes, the application distinguishes the following roles: public, registered user, parking provider, magistrate (city authority), police inspector and admin. Different roles have access to different data from different parking lots. For example, admins are interested in the status of sensors, city and parking providers are interested in statistics on parking lot occupancy, public users are interested in current occupancy and price and police is interested in how long a vehicle parked.
 

Q: Which role was your key focus?
A: So far, top priority is given to the city and public users, since the cities demand to implement the solution. I should also mention, that most parking providers are now sceptical about the price data and see them as an unnecessary cost, but we hope that real operation numbers will convince them as well.
 

Q: Is there any demand for your solution?
A: Yes, as mentioned earlier, this project raised interest, because it’s got good implementation potential. First order came from one Slovak city asking for a mobile application. With the second Slovak city there is an agreement to implement this solution for testing purposes.
 

Q: When can we park with your application for the first time?
A: The exact date is not given yet, but soon. There are some real sensors drilled in STU FEI parking lot, which are in pilot version.
 

Q: How do you plan to develop the project in the future?
A: According to the plan  is the redesign of mobile version of application, which is in progress. The next step is to implement payment gateways, so that drivers can buy tickets online, then it is extending of user profiles (adding license plate number), in the distant future, we can talk about predictions of occupancy and other data mining methods. In connection with this, one topic for the bachelor thesis was announced in our faculty for the next year. Also, the application processes only data from our sensors, but we should extend the solution to process data from existing parking monitoring devices.