Adilson S. Cardoso
ECE4007-L01/Dr. Wit Smith
Group Name: Cerebral Palsy
Wearable computing and input devices
Introduction
Everyday we use our hands to interact and maneuver with our environment in a
variety of tasks such as cleaning, typing on keyboard computer, writing, and grabbing
objects. A considerable amount of research effort has been and is continually devoted to
developing technologies for studying interaction and manipulation and for augmenting
our abilities to better perform many of these tasks [1]. “Wearable computer” is a
particular area of research that focuses on how to interface the user with a computer
without using the traditional input/output devices, mouse, keyboard and monitor.
“Wearable computers are generally composed of small sized PC, display mounted on
head, wireless communication hardware and an input device. Wearable computers are the
next generation of portable computers. Worn by people, they provide constant access to
various computing and communication resources” [2]. This report will focus specifically
on the state-of-the art input devices for wearable computers, identify commercial
available technologies, and the building blocks for implementing an input device such as
a data gloves for wearable computers.
Commercial Applications
In most applications, computers and its input devices are used to access or send
information while performing a specific task. In contrast, the wearable computer is not
the point of focus like the mouse, keyboard, or monitor, rather the wearable computer
input device it is used as a tool [3]. Wearable computers, in particular data gloves, have
been increasingly employed in the areas of teleoperations and robotic control, surgery
training of medical applications, entertainment sports of virtual reality systems, industrial
manufacturing of CAD/CAM applications, maintenance applications such as aircraft
cabin application and so on [4].
“Glove-based systems are used to interact with computer-generated (typically
virtual reality) environments. Using a computer screen or a head-mounted display, the
user, who can be located either on site or remotely over the Internet, can visualize
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environments or artifacts that are being designed before their actual construction or
manufacturing, eliminating the need for expensive mockups. In the industrial world,
Daimler-Benz and Boeing were among the first to develop virtual reality systems for
design [2]. Daimler-Benz’s testers could select between different furnishing options and
models for Mercedes interiors using Data Gloves [3]. Boeing’s designers and maintainers
could evaluate and test the military aircraft Joint Strike Fighter using “CyberGloves.”
Designers could “walk” around a virtual aircraft as if they were on a carrier deck and
simulate maintenance tasks (i.e., loading a weapon or removing a part)” [1].
One particular wearable input device that is considered futuristic is the
“Lightglove.” According to its inventors, “Lightglove” uses light generated from the
device LED or infrared to scan the palm while sensing the wrist, hand and finger motion.
The acquired data is interpreted wirelessly by a computer into either on-screen cursor
control or key closures, and it can also be used as a long distance on/off switch for
practically all electronics [5]. However, the company Lightglove.com, the product will
not be accessible to the consumer market until further notice due to manufacturing
capabilities[5]. The “Lightglove” can be used with any existing computer system that has
wireless capability (i.e. Bluetooth). The device is also easy to configure, easily
maintained, and most importantly provides excellent feedback response. However, there
are many other glovelike wearable input devices that employ other sensor technologies,
such as Reusch Sonic Control Glove, Digital Data-Entry Glove, CyberGlove,
and
SCURRY.
Underlying Technology
The most commonly used sensors in the development of glove based input
devices for wearable computers are, acoustic tracking sensor, optical tracking sensor,
magnetic tracking sensor and resistance tracking sensor. The acoustic sensor uses high
frequency audio signals to track the movements of the fingers; however, this type of
sensor is prone to acoustic reflections [2]. An optical tracking sensor usually employs
LED or infrared signal as the source and a photocell sensor as the receiver to measure the
intensity of the signal. As for the Magnetic tracking sensor, it uses a source element
radiating a magnetic field, and a sensor acquires the signal and reports its position and
orientation with respect to the source. The accuracy of measurements will diminish due to
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metallic objects in the environment that interfere with magnetic fields of the source. The
resistance tracking sensors use variable resistance material whose resistivity is varied
according to the bending degree of the sensor. The main drawback of resistance tracking
sensors is that the sensors are susceptible to fast wear and tear which may output
erroneous data [4]. An example of the optical tracking sensor is the state-of-the-art
“Lightglove” wearable computer input device described in the previous section. The
device communicates with a computer using a Bluetooth 2.0 transmitter; it has fully
integrated software and hardware and uses a rechargeable lithium battery. According to
product description “Lightglove” is an excellent product concept because it is easy to
handle user friendly, and it has quick feedback responses when interacting with computer
for various applications (i.e., playing a virtual piano, controlling a mouse click, typing on
a keyboard).
Building Blocks for Implementation
When designing wearable input devices such as glovelike tool, usually both
hardware and software are required. Signal processing is required to translate the input
signals from sensors into the the microcontrollers. Analog to Digital Converters (ADCs)
are also used with operational amplifiers and low-pass filters to condition the signals
from sensors (i.e. gyroscopes, pressure sensors, accelerometers, MEMS inertial sensors,
optical sensors) before feeding it to microcontrollers [6]. To wirelessly transmit the data
computed by the microcontroller to a computer transceivers are used. The most common
are the RF (at 2.4 GHz), Bluetooth and optical transceivers. As for power sources lithium
batteries are the optimal sources of power with a typical power consumption of 34mA at
3.3V [6]. For non wireless devices, USB ports are used for both power and device
communication.
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References
[1]
Dipietro, L.; Sabatini, A.M.; Dario, P., "A Survey of Glove-Based Systems and
Their Applications," Systems, Man, and Cybernetics, Part C: Applications and
Reviews, IEEE Transactions on , vol.38, no.4, pp.461-482, July 2008.
[2
Wang, K. Chen and Y. S. Ong, “Advances in Natural Computation” in An
Improved Information Retrieval Method and Input Device Using Gloves for
Wearable Computers, Changsha, China: Springer Science & Business 2005, pp.
1179-1184.
[3]
Albrecht Schmidt, Hans-w. Gellersen, Michael Beigl, Ortwin Thate “Developing
user interfaces for wearable computers: Don’t stop to point and click”. In
International Workshop on Interactive Applications of Mobile Computing
(IMC2000). Warnemünde, Germany.
[4]
Chin-Shyurng Fahn; Herman Sun, "Development of a data glove with reducing
sensors based on magnetic induction," Industrial Electronics, IEEE Transactions
on , vol.52, no.2, pp. 585-594, April 2005.
[5]
Light Glove, “Virtual PC Remote with light buttons,” [Company Website],[cited
2008 September 3rd], Available HTTP: http://www.lightglove.com/infofr.htm
[6]
Yoon Sang Kim; Byung Seok Soh; Sang-Goog Lee, "A new wearable input
device: SCURRY," Industrial Electronics, IEEE Transactions on , vol.52, no.6,
pp. 1490-1499, Dec. 2005.
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