Blo - Multimodal Interaction
with User’s Forced Exhalation
Information and Interface Design,
National Institute of Design, R&D Campus,
Abstract: “Blo” is a multifunctional digital input device The blow of air has different parameters like
that accepts forced exhalation from mouth and its pressure, temperature, duration etc which are sensed
variations thus adding a new dimension to the human- by the use of different sensors  placed in the
computer and human-machine interaction. This new device categorized on the use and the scenario in
attempt has a potential to tap our natural actions to which it is used. These sensors record different
address certain challenges faced in conventional readings and send the data to the microprocessor for
methodologies and introduces new possibilities of
processing which in turn controls the
applications. This paper introduces you to the concept
of Blo in a detailed way and discusses the various operations/performance of the devices.
scenarios in which Blo can be used.
Blow of air can be taken as an input in
addition to the text input for better usability features.
Keywords: multimodal interface, forced exhalation, This design can be embedded in different gadgets as
impairments, sensors. an added accessibility feature. New product can be
designed mostly like handheld to take the blow of air
as input and perform different actions when
I. INTRODUCTION connected to different devices.
The predominant mode of human computer
interaction  has not changed substantially since the II. ANALYSIS OF HUMAN BREATH
creation of the windows, icons, menus and pointers
more than thirty years ago. In many ways, they are Human respiratory system has two cycles –
still convenient and efficient ways for interaction. inhalation and exhalation .
However research and considerable work on Inhalation is initiated by the diaphragm and
voice/speech input, handwriting, sketching, and supported by the external intercostal muscles. When
gesture based inputs is done as naturalness in the diaphragm contracts, the ribcage expands and the
interactivity can provide much better learnability, contents of the abdomen are moved downward.
flexibility, memorability, convenience and efficiency. Exhalation is generally a passive process; however,
active or forced exhalation is achieved by
Blo is a design which uses human breath the abdominal and the internal intercostal muscles.
(blow of air) taken as Blo-input [I would use ‘Blo-
input’ in place of “blow of air from mouth” in the During this process air is forced or
following pages] which aids in interaction between exhaled out. The lungs have a natural elasticity as
humans and the computers/machines. This enables they recoil from the stretch of inhalation, air flows
users to use a natural way to interact with the back out until the pressures in the chest and the
electronic gadgets and computers or sometimes even atmosphere reach equilibrium.
to perform the electrical and mechanical operations. During forced exhalation, as in blowing out
This is a new interface that connects the instincts of a candle, expiratory muscles including the abdominal
human blowing in various situations. muscles and internal intercostal muscles generate
abdominal and thoracic pressure, which forces air out
of the lungs. Hence the air exhaled has the
temperature of the Body and the relative humidity, wiping away the dust, flying kisses to loved ones,
close to (water vapor) 6 %. moving light things (like the pen which is about to
roll off the desk), soothing wounds to make feathers
Some of the characteristics (variable parameters) that
float in the air, which was one of my favorite pastime
human breath has are:
during childhood. If we see, in many cultures
blowing off air is a major part in the people’s daily
Humidity / Relative humidity – it varies with the
life that we can easily connect to.
temperature of the air blown.
Temperature – the blown air has certain temperature
by placing the input device far or near and also by IV. SCENARIOS
increasing the aperture formed by the lips and
muscles near the mouth.
Pressure – the pressure at which we can blow the air The Blo concept appears more meaningful and useful
is variable, we can exert more pressure or less as I project the scenarios where it can be used. Of
pressure by controlling the intercostal muscles of course the design of the concept and device would
lungs. vary according to the scenario.
Duration – the duration for which we can blow the Some of the user groups that would be involved in
air is variable. However a limit of 2-3 seconds is different scenarios are:
considered comfortable Users with multiple disabilities and impairments like
Focus – the focus can be varied by controlling the hearing/speaking/visual impairments, paralyzed/
muscles near the mouth, by controlling the aperture movement impairments.
formed by the lips and by positioning the mouth. Users in wet conditions/ electrically conducive
Chemical Compound: Our breath consists of certain environments.
taste /flavor compounds  [refer Table (1)] mixed in Children.
the water vapors (lemon flavor / mint / alcohol) Mobile phone users.
Aromatic Fragrance Occurrence Structure Wheel chair for paralyzed or users with limbic
Compound movement restriction: Usually when the user cannot
move limbs needs an automatic wheelchair with an
electric motor fitted, with which s/he can move and
Citronellal Lemon Lemon reach his/her destinations. Those wheel chairs usually
have push buttons /joystick to operate which can be
found difficult for the users.
By using the Blo they can start/stop/turn the
Eugenol Clove Clove wheel chair with the air-Blo input. The interface can
be a simple mouthpiece projected before the user
immediately after s/he occupies the chair.
A new language for users with multiple
Ethyl Sweet, Wine impairments by integrating symbols/visuals/vocals
acetate solvent integrated with the Blo signs patterns [similar to
telegram’s Morse code]. For the users with hearing
Table (1).Aromatic Chemical Compounds and speaking disabilities Blo-inputs (a pattern)
transformed into visuals or others can bring
excitement and completeness to the communication.
III. BLOW – PART OF OUR DAILY LIVES
A Blo design can be used to switch On/Off
power or operate electrical equipment in wet or
The most soothing thing that my mother would do electrically conducive environments like drilling or
when suddenly some dirt hits my eye, was to blow mining without actually being in physical contact.
some air onto her sari and place it on my eye. Electrical appliances in kitchen are mostly touched
Birthday parties are never complete without blowing with wet hands which lead to hazards like short
off the candles. My father would clean his circuit and electric shock as seen in Figure (1.a) &
motorcycle mirror by blowing vapor onto it and then (1.b). Blo would make the interface hands free and
cleaning it with cloth. The list of such common and thus preventing the hazards (washing machine,
natural instincts would go from providing warmth, microwave ovens, lights, mixers).
(Water on switchboard)
(Blo-input to the mobile)
Figure (1.a) & (1.b) Switch boards in kitchen prone to short circuit
A game for children to generate patterns of
colors by varying the pressure of the blown air /
(Sending message display)
humidity of blown air. A wide range of spectrum can Figure (2.a) & (2.b) Sending Message via Mobile using Blo
be produced and being an interactive game for
children by relating air to color it explores a new
possibility. This could also be an alternative to play V. HOW DOES BLO WORK ?
Holi - A festival of colors in India or Abroad by
integrating it with the networking and wireless
Blo works by taking the blown air input from user
communication technology. This virtual coloring can
that is sensed by the sensors against different
protect people from getting hurt/can save lot of
parameters like temperature, pressure, humidity,
water/can be played across the globe.
duration of the flow, chemical compounds.
Generating colors on the basis of taste: For
The data is then recorded in the microprocessor (like
example if lemon is tasted and air is blown into the
arduino , PC etc.) and the values which fall in the
Blo device, the compounds in the vapor have certain
threshold limits are considered and processed.
chemical compounds that are detected by the sensor
According to the program the different values
and a color pertaining to lemon and thus yellow can
recorded give different outputs. Figure (3) shows the
be projected. Similarly with other flavors various
system design of Blo.
colors can be mapped. The game interprets the taste
Of course the sensors used, the processor,
the program depends on the scenario in which Blo
device is used. Since the work is in the conceptual
Remotely operating mechanical operations
phase I would prefer to provide the technical
with much less effort: Increasing/ Decreasing the
specifications, samples later after prototyping.
speed of fan, closing / opening the door can be done
through simply blowing the air.
Clearing the text on PC monitors, usually
we have the tendency to wipe of the dust by blowing
air. Similarly we can use the act to clear off the text
on the screen.
Sending the text message in mobiles (See Figure 2.a
& 2.b) are others which strongly connect to the
human behaviors or natural actions.
There are several possible listening or input modes
Always listening – The device is always ready to take
the Blo-input and responds with the appropriate
Push to blow – The device can be made ready to
accept the Blo-input by pushing a button, especially
in the computer applications and mobile usage
scenario to send messages, to clear text etc.
Blow the air after pressing a button and the device is
active and taking the input till the button is pressed
again. This is useful in coloring game scenario where
the user can switch on the device, play and again put
Figure (3). Blo-System Design
Screen layout, colors, and background music also
VI. MODES AND FEATURES OF BLO create moods in multimodal user interfaces. A
background music acknowledging the Blo-input and
color and visual display would enhance the
Some of the features incorporated on Blo to make the interactivity.
users comfortable during the interactions. 
Users need to know when the device is listening to VII. FUTURE DEVELOPMENT
them speak and when the device is not listening.
Operational status can be presented as an LED light
indicating the operational status of the device and By integrating it with touch/text and voice we can
also indicating the power status and in case of battery enhance interface model since its appeal is very
usage the status can be displayed as how much longer natural to human and as it can blend well. The
the device will be operational. combination of the other modalities gives a greater
Also since Blo device is used by users with control and more combinations to interact with
visual impairments a vibration technique can be used machines. It can really help in the multitasking
to denote the power status.eg: when the device is low environments, where the user is restricted to limited
on charge it vibrates with a warning tone. limbic actions, with respect to the human-computer
interaction Blo can bring an easy, natural and hands
free way to control better and have richer interaction.
Alternate Option: Further work can be done in making a simple
If the user doesn’t want to use Blo in any case there language by observing the patterns in Blo-inputs.
is an alternate option to operate or perform the Development of more applications in different
activity through other input modes (push buttons, text environments (automotives, learning etc.) simplifying
input etc) provided according to the scenario. or enhancing the interactivity.
I would materialize this concept by building a
Response time: prototype. Later would take it forward by doing a
Response times greater than 5 seconds will user experience study to evaluate the effectiveness of
significantly reduce usage. If a response time exceeds this multimodal interaction.
this limit, the user is informed that the computer is
busy processing the request.
Human being today is surrounded by various
technology and gadgets thus in turn increasing the
possibilities of new interfaces and interactivity. A
good design is the one that puts least information
load and that uses the existing natural actions/habits
Blo is an idea on these lines which can bring many
more possibilities and enhancements in the Human
Computer/Machine Interaction field. It can open the
doors of new applications by capturing the natural
actions of the human behavior without any
enforcement on the users. It qualifies as a universal
design as it considers users across ages, cultures, sex,
The usability factor here has been addressed by
considering various conditions and situation;
however it can be further maximized by coupling it
with other modalities in interface.
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