This document proposes a virtual numeric keyboard for mobile devices using echo sound techniques. Sensors would detect finger positions over a projected virtual keyboard and send data to a microcontroller via Bluetooth. The microcontroller would compare sensor data to predefined key positions and types. An Android app would display the corresponding key on the mobile screen. Formulas are provided to calculate distance from ultrasonic sensor data. The technique aims to enable virtual typing with low implementation costs and no harm to users.

1. Virtual Numeric Keyboard for mobile devices using Echo
Sound Technique
Mr. Harshal Prakash Ahire, Mr. Amid Feroz Patel
KJ's, Trinity College of Engineering and Research Pune-48, Maharashtra India
harshalahire9@gmail.com, amidsaif@gmail.com
A B S T R A C T
As we all are aware about the scope of virtual world, mobile phones are also trying to get virtual.
Many companies are doing the research to make the virtual keyboard and virtually operate able
mobile phone In this paper we proposed a new technique in which we are going to create a virtual
keyboard for the mobile device, this keyboard is will be virtual and we will able to communicate
with phone just typing on the virtual keyboard. This approach of implementing the virtual
keyboard is having less implementation cost as compare to other approaches, as well as it is not
harmful to the user who is going to use it. We are going to create a virtual keyboard in which we
will show the numeric keypad, which will have the numbers 0-9. The user is going to type
virtually and that number will be get printed on the mobile phone screen.
Index Terms: Virtual Keyboard, Echo Sound Technique, Formulae and Calculation.
I. INTRODUCTION
In this paper we are going to Design the virtual keyboard for the mobile device which is going to reduce
the human efforts to do the operation on mobile device such as typing, etc. In this approach keyboard will
be projected on the ground, we will be using the echo sound technique to do the operations hence we are
going to make the use of ultrasonic sound sensors.
Ultrasonic sensors are used to calculate the distance. We are going to calculate the distance of finger
whichever placed on the virtual keyboard. The Sensors are going to calculate the distance of the finger
placed. The distance will be store in the database and will get compared with the calculated or defined
data. After comparing data generated by sensor with the data present in the database, the defined key is
going to type on the mobile device.
The Ultrasonic Sensors which we are going to use is having capacity to sense the distance of obstacle in
range of 200cms. The sensors will be connected to a microcontroller which will be going to send the data
to the mobile phone.
II. EXPLANATION
A. Virtual Screen
We are going to use the projector of the mobile device to create the virtual screen, this virtual screen is
important because we are going to type on this screen only, we are going to use the reflectors to make the
screen visible to human being in well format. The angle of the reflector is the most important thing,
because if there is a little difference in the angle of the reflector the output will get changed. The Virtual
screen which is projected on the ground will exactly same as that of the mobile screen. The distance of
the each key is different from each other and the key size is of each key is fixed and same for more
information [Figure: 2 and 3].

2. B. Sensors
Sensors are the main thing of the project, we are going to take the user data via sensors only, sensors are
going to record the data and transfer the data to the microcontroller, the ultrasonic sensors are having
capability take or read the data in “Parabolic” manner. It is making a parabola from the sensors in range
of around 200cms. The data captured by the sensors will be in the form of centimetres. The data of each
key is having one starting point and one ending point as well as the edges of the key are defined in the
code only so it is going to capture the data and compare it with the database, and the most suitable
output will be displayed on the output screen, for more information [Figure: 2].
C. Microcontroller
We are going to use one microcontroller, this microcontroller is going to send the data which is capture
by the sensors. This data is sent to the mobile device via Bluetooth. Microcontroller is having the physical
connections with the sensors as well as with the Bluetooth module. The physical connection is done with
the help of wires. These wires are fixed in breadboard and the hardware device, for more information
[Figure: 1].
D. Android App
The device will require and android app which can display the required output on the mobile screen. The
output will be in the form of keys ranging from “0-9”. The Android app is expected to show the exact key
which will be pressed by the human on the virtual keyboard.
III. Algorithm to Implement
Step 01: START
Step 02: Switch the projector on and make the settings of the reflector.
Step 03: Turn on the App of the mobile.
Step 04: Switch on the sensor.
Step 05: Check the Connections of the hardware are fine or not.
Step 06: Connect the Bluetooth module to the Mobile device.
Step 07: Check all connections of hardware as well as the Bluetooth Connection, IF they are not
working properly go to Step no: 2.
Step 07: Now whole project is working so we are able to do the operations.
Step 08: Now we are able to write on the virtual keyboard, and it will get printed in the mobile device.
Step 09: Switch of the App
Step 10: Switch of Sensors.
Step 11: Switch off Projection
Step 12: END
IV. FORMULAE AND CALCULATIONS
I. Formula for calculating the distance of the finger from sensor in centimetres is:
Distance = microseconds / 29 / 2;
Explanation: microseconds is nothing but the time required by the waves to go from the sensor and again
come back to receiver by getting reflected from an obstacle.

3. It’s divided by 2 because we have to calculate the one-way distance means the time required by the wave
to travel till finger. And we have divided by 29 because we have to convert that time in distance.
Fig 1: Mobile Device With all Hardware

4. Figure 2: Mobile Device with Virtual Keyboard as well as with Hardware
Figure 3: Virtual Numeric Keyboard
V. FUTURE WORK
We are planning to do all operations of mobile phone virtually, like calling, watching movies, playing
games, and all operations of mobile phone.
VI. CONCLUSION
From this paper we get how to create the Virtual Keyboard for Mobile Device and this created device is
efficient to use in any conditions as well as it is in budget of a common man.
VI. REFERENCE
[1] Mr. Amid Feroz Patel, Mr. Harshal Prakash Ahire, Projection Virtual Keyboard and Virtual Screen
for Mobile Phone, International Journal of Advance Foundation and Research in Computer
(IJAFRC) Volume 2, Special Issue (NCRTIT 2015), January 2015. ISSN 2348 – 4853.
[2] Muhamaad Haroon Yousaf, Ha_z Adnan Habib, Kanza Azharm Fawad Hussain, Muhammad
Rizwan, Malik Muhammad AsimTowards the develpment of virtual keyboard: An activity
recognition aaproach, Life Science Journal 2013;10(10s).
[3] Ha_z Adnan Habib, Muid Mufti Real time mono vision gesture based virtual keyboard system,
IEEE transaction on consumer Electronic , vol 52, no.4.
[4] Camillo J. Taylor Virtual Keyboards, Published IEEE November 23 /- 1993.

5. [5] Samit Bhattacharya , Debasis Samanta and Anupam Basu Performance models for automatic
evaluations of virtual scanning keyboards, IEEE transaction on neural Systems and rehabilitation
engineering vol.16,no.5,october 2008.
[6] Sayan Sarcar, Soumalya Ghosh, Pradipta kumar saha, Debasis samanta Virtual keyboard
design:State of arts and research issues ,proceedings of 2010 IEEE students technology
Symoposium 34 April 2010, IIT Kharagpur.
[7] Miroslav Hagara Jozef Pucik , Peter KullaAccuracy of 3D camera based virtual keyboard, 978-
14799-3715-8/14 copyright 2014 IEEE.
[8] Syed Ashklaq Hussain Shah Ali Ahmed, Ifekhar Mahmood, Khurram khurshid Hand gesture based
user interface for computer using a camera and projector, 2011 IEEE international conference on
signal and image processing applications.
[9] Ming he, jun Cheng and Dapeng tao Touch sensitive interactive projection system, 2014 IEEE
international conference on security pattern analysis and cybernetics(SPAC).
[10] Huan du, Thierry Oggier, Felix Lustenberger, Edoardo Charbon A virtual Keyboard based on true -
3D optical ranging, Zurich , Switzerland.
[11] Jun Hu; Guolin Li; Xiang Xie; ZhongLv; Zhihua Wang Bare-_ngers Touch Detection by the Button's
Distortion in a Projector-Camera System ,, inCircuits and Systems for Video Technology, IEEE
Transactions on , vol.24, no.4, pp.566-575, April 2014 doi: 10.1109/TCSVT.2013.2280088.
[12] Nirav Shah, Saumya Lehera Virtual keyboard projection, International Journal of Students
research in Technology and Management Vol 2(01), Jan – Feb 2014, ISSN 2321-2543,pg 2628.
[13] Miroslav Hagara Jozef Pucik Speci_cation of Camera parameters for virtual key board, 978-1-467-
35517-9.