Keywords

1 Introduction

Text-based communication is very popular in today’s generation as it is quick, context-free and recordable. However, in order to communicate via text, one must have the receiver’s contact information, such as their phone number or email address. Therefore, messages cannot be sent to an indefinite number of people. In case of location-aware apps, it may be useful if one can send a message to all those present in a particular area.

The system is an Android mobile application which, upon installation, can be used to send messages to those in the vicinity of the user as long as the receiver or receivers themselves have the same application. Thus, its main purpose is to provide location-specific information in real-time.

This is comparable to natural human communication in the real world, where one can even approach strangers for help or to know more about the location. In such a case, one can even know the response of the person immediately by observing their facial expressions, which is not possible with text-based communication. Thus, the system combines the advantages of verbal and text-based communication to provide a convenient means of communication among people in a specific area.

This app facilitates communication among those who have met for the first time and are at a similar location, without the need for exchanging contact information first. Thus, this method has been developed for extremely short exchanges. Moreover, the information provided in the messages will be kept as a record and can be used later.

Thus, the focus is on the receipt of useful information rather than on the sender-receiver relationship or on the socializing aspect which is still possible in case there are some interested parties. Even if communication may have been initiated via the cyber-space, since the users are within eyeshot of each other in the real world, they may use this initial contact to further communicate verbally as well. Therefore, this system can be used to supplement verbal communication or provide an alternative to it in case verbal communication is not convenient or desired.

2 Features of the Ninja Messenger

This app has been created using native Android code, that is, using Android studio, the recommended IDE for Android app developers. The main language used for the code is Java, with XML being used for the GUI. We have incorporated the latest Android material design concepts and suggestions into the app. The SQLite database is used to store the messages for later reference.

There are three methods by which a user can send messages. Each method can be used in different situations as they serve different purposes.

  1. 1.

    Shuriken mode

In this mode, the sender can send a message to another user who is in their direct line of sight by pointing the mobile device in the direction of the intended receiver and sliding one’s finger across the screen after the message is typed. This method is helpful for direct, context-free, short-term communication.

  1. 2.

    Noroshi mode

This mode is for sending the same message simultaneously to all users within a certain radius of the sender’s device. Upon writing the message, the sender must aim the mobile device at the sky and perform the sliding gesture. One can think of this as the messaging equivalent to making an announcement on a loudspeaker, without the noise.

  1. 3.

    Makibishi mode

In this mode, after the message is typed, the sender directs his or her mobile device at the ground. The message is received by any user who passes that point during the life span of the message (Fig. 1).

Fig. 1.
figure 1

A pictorial representation of the three modes of message transmission

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3 Applications

The applications of this mobile app may vary depending upon the mode being used. One general application for all 3 modes would be advertising. This app could be convenient for sending location-specific advertisements such as information about nearby shops, restaurants, tourist spots, et cetera or available special offers and discounts in those places (Table 1).

Table 1. Information on the effects of the power of sliding
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  1. 1.

    Shuriken mode

The advantage of this form of communication is that it can be used for a one-time communication with a stranger without having to provide one’s own contact information.

For example, when asking for directions, the user could use this app to receive the directions in writing in case they forget or get confused and need to double-check. In this case, the user is more interested in the information than developing a relationship with the sender.

Another situation is when the sender does not want to disrupt the peace of the area by calling out to the receiver or does not want those around to hear the message intended only for the receiver. In such a situation, a text could be more convenient than speech-based communication.

  1. 2.

    Noroshi mode

In any specific room such as a classroom or an office, a user may send a text to all those in the room to ask if anyone has some time to help the sender with some project or assignment.

Another case could be to raise awareness or send notices which concerns everyone in a particular location. This could be useful in case of any sudden news of possible danger in an area.

  1. 3.

    Makibishi mode

This mode can also serve the purpose of providing area-specific information. However, it is different as its focus is a specific location point. Since the message will be received by anyone who passes a particular point, there may be different kinds of messages left at different points by the sender even in the same room.

One interesting application would probably be to construct treasure-hunt type activities. Other applications include providing information or route guides at points where the road branches off or at the entrances or exits of shops, malls, offices, et cetera.

4 GUI of the App

The following are some screenshots of the application (Fig. 2).

Fig. 2.
figure 2

The login page

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5 System Requirements

Firstly, the user must own a smartphone which has an Android OS, preferably version 5 or above with the app installed (Fig. 3).

Fig. 3.
figure 3

This is an example of what will show on the map when two devices are near one another.

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Secondly, the app requires location permissions since the tracking of those in the nearby areas is mainly done using the GPS (Fig. 4).

Fig. 4.
figure 4

Page with the Shuriken mode selected. The interface is similar for the Noroshi and Makibishi modes as well. The blank space will be filled in with the history of recorded messages once the user starts using the app.

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Thirdly, the app should have access to the Internet so that the messages can be transmitted. This can be in the form of Wi-Fi, GPRS, etc. (Fig. 5).

Fig. 5.
figure 5

Upon pressing the floating action button, the screen shown on the left will appear and upon pressing the “done” button, the message is displayed in the form of a cardview which can then be swiped in order to send the message. Also, depending upon the mode, some relevant instructions about the direction in which the user needs to swipe will appear.

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Lastly, for the determination of the orientation and intensity of the sliding gesture, a 3D acceleration sensor and magnetometer must be present in the mobile device.

6 Conclusion and Future Work

Thus, this app has the potential to provide a convenient means of communicating even with strangers for a brief moment without the need for exchanging contact information. Moreover, the information provided in the messages will be kept as a record and can be used later.

Apart from incorporating the basic functions described in this paper, there is scope for many more added features, the most important being the security features. It is possible that certain persons may try to misuse the app. They may send spam mail or advertise aggressively through the app. In such a case, we would like to add the feature of reporting such behavior or straightaway blocking such a user.

Secondly, in the Makibishi mode, when a person receives a message by passing through a specific location point, he or she may want to find out more about the contents of the message. For this purpose, they may want to directly contact the sender of the message. Hence, an option to send a direct message to the concerned person may be facilitated.

Apart from modifications, we also plan to test the app practically. This means that volunteers will be asked to install the app and use all of its features. Then they will be questioned about the ease of understanding and maneuvering of the app and what questions arose during its use. We would also like to find out what scenarios the users felt they could use the app in. Also, we hope to receive feedback about the user interface.

The feedback will help with the analysis of the comfort and convenience of using this app. After receiving feedback from the volunteers, some modifications might be required.

The potential users of the app may be anyone with a smartphone running the Android OS. Although the iOS version of the app may be developed in the future to reach a larger group of smartphone users.