INTRODUCTION
Skin put allows the users to simply tap their skin in order to controls the various features
like audio systems, video games, making phone calls, and navigate hierarchy browsing
systems. In Skin put, a keyboard, menu, or other graphics are projected on a user's
palm and forearm from a pico-projector embedded in the armband. The acoustic
detector in the armband then simply determines which part, the user activates by touch
which was displayed on the user's screen. As shown in figure 1, the researchers explain
the variations in the bone density, size, and mass, as well as the filtering effects from
the soft tissues and joints, which mean different skin locations, are acoustically distinct.
The software then matches sound frequencies to specific skin locations, which allows
the system to determine which "skin button" the user pressed.
Figure 1 shows the use of human skin as a touch screen. The Skin put has been
publicly demonstrated as a armband. This prototype has ten small cantilevered Piezo
elements which are configured to be highly resonant, sensitive to frequencies between
20 and 80 Hertz (Hz).
RELATED WORK
Skin put is an amazing bluetooth-enabled device which was developed by scientists
from Mellon and Microsoft that allows the users to use their skin as a touch screen to
control their phone, MP3 player or gaming options. It is operated by using a bio-acoustic
sensor that has capability of sensing and this technique allows your body to be used as
an input surface. When the user tap their finger on their skin, the impact thus creates
acoustic signals which is measured by the device. To capture these signals created,
scientists develops a bio-acoustic sensing array which has capability to listen for impact
and then classifies them .
BIO-ACOUSTICS
The mechanical phenomena that enable the Skinput, have a specific focus on the
mechanical properties of the arm which is demonstrated here. Skin put sensor and the
processing techniques that are used to segment, analyze, and classify bio-acoustic
signals are discussed in this section. Some of the acoustic energy produced when skin
is tapped with finger is radiated in the air as sound waves; this energy is not captured by
the Skinput system. Among this acoustic energy transmitted through the arm, the most
readily visible waves are transverse waves, which are created by the displacement of
the skin from the impact of finger. When shot with a high-speed camera, they seem to
appear as some ripples, which then propagate away from the point of contact. Then the
amplitude of these ripples is dependent on both the tapping force and the volume and
compliance of soft tissues under the area of the impact. This is demonstrated in figure 2
below.
SENSING
To capture the rich variety of acoustic information, many sensors have been introduced,
including terms for instance, bone conduction related microphones, and some
microphones are coupled through conventional galvanometers, stethoscopes, and
accelerometers. Foremost, most of the mechanical sensors are constructed in order to
provide comparatively flat response curves over the wide range of frequencies which is
relevant to the signal. This is the requisite property for wider range of applications where
a faithful representation of an input is desired. However because only a certain set of
frequencies is captured through the arm as a response of tap input, a flat response
curve( as shown in figure 3) leads to the capture of undesirable frequencies and thus to
a high signal to noise ratio (SNR).
Additionally, the figure 4 clearly shows accuracy levels for different position sets.
Moreover, the conventional cantilevered sensors were generally less sensitive towards
the forces which are parallel to the skin (e.g., routine shearing motions as a result of
stretching). Thus, the random stretching of the skin resulted by many routine
movements (e.g., reaching for a doorknob) tends to be attenuated as per the property of
the skin structure. However, the sensors up to a large extent are responsive to the
induced motion perpendicular to the skin plane - perfect for capturing the frequencies of
transverse surface waves and longitudinal waves emanating from interior structures of
the skin. Eventually, this sensor design is comparatively inexpensive and can be
manufactured in a very small form factor.
ARMBAND PROTOTYPE
The final prototype as shown in figure 5 above includes two arrays of five sensing
elements, gathered into an armband (prototype) form factor. The idea to have two
sensor packages was motivated by some focus on the arm for the touch input. In
particular, when placed on the upper arm (above the elbow), it was expected to gather
the acoustic information from the gazed area in addition to the sensible area on the
underside of the arm, with better acoustic coupling to the Humerus, which is the main
bone that runs from shoulder to elbow.
PROCESSING
In this section, the processing of the armband design is discussed. The audio stream
was divided into segments of individual taps using an absolute exponential average of
all the specified channels. This stage is incorporated with set of several examples of
each input location. The results observed must be considered as a baseline. For a
better collection of acoustic information, it is advised to place the sensor arrays just
below the elbow, on the forearm.
FUTURE SCOPE
Presently, the acoustic detector can detect up to large extent five skin locations with an
accuracy of 95.5%, which refers to a sufficient and reliable versatility for many
nowadays mobile applications. These useful results render this armband prototype
suitable for inclusion in future devices, for instance an arm-mounted portable audio
player. The prototype system can be imagined to use wireless technology like Bluetooth
to transmit the commands to the device being controlled by it (such as a phone, iPod, or
a computer -figure 6) in easiest way. The researchers say that this system also works
well when the user is walking or running.
CONCLUSIONS
In this paper, the work has been incorporated in order to appropriate the human body as
an input surface. This includes tapping the skin (input surface) with different parts of the
finger and simultaneously distinguishing between materials and objects. The work has
been done to describe a portable and reliable, wearable bio-acoustic sensing array (the
armband) in order to detect the gazed locations resulted from the finger taps on the
forearm and hand. The results from the experiments have described that this system
performs very well for a series of skin gestures, even when the user is moving. In
addition, the observed results demonstrate other practical applications of the project's
approach, which we hope to further explore in future.
DIAGRAMS
FIGURE-6:- WIRELESS & SKINPUT

Claim-
Here we are claiming to use the human skin as a touch screen which will bring a
change in electronic era. As today's users are annoyed using tiny touch screens on
mobiles, tablets and other electronic gadgets. They need a change in this area and we
tried here to bring a change. They might get attract here in this new technology and
want to use it in their daily life.