by Bryan Bergeron, Editor
Afundamental application of electronics is transformation —
from power supplies that transform AC to DC to microprocessors that transform binary code to text, graphics, and
sound. While transformations at many levels may be critical to
Table 1. Sensory Transformation Matrix showing
Vibration Pressure Hearing Vision
Frequency Light Organ
Additional headers not listed at the top also include: Proprioception, Taste,
Smell, Temperature, and Pain.
the function of a device or application, it’s the high-level
sensory transformations that hold the greatest potential to
change the world. I’m talking about the high-level transformation
of sensory experiences, illustrated at one level by Craig Lindley’s
article on a digital color organ in this issue.
Transforming sensory data from one form to another has
both entertainment and pragmatic value. For example, a color
organ that transforms sound amplitude and/or frequency to
colors can serve as an entertainment device and as an aid to
configuring the graphic equalizer front-end of a stereo system.
More significantly, sensory transformation may be used to augment normal senses and to supplement damaged sense organs.
Consider the matrix of potential sensory transformation in Table
1 as an aid to exploring how sensory transformation can be applied
to correct a sensory deficient or to augment a person’s normal abilities. The matrix is an over-simplification to the extent that each sense
may take on several variables or may be modulated. For example,
hearing may involve the perception of pitch, amplitude, and direction, and vision can encompass color, intensity, movement, and size.
A prominent feature of the transformation matrix is that it is
sparse — with a few prominent exceptions, sensory transformation is largely unexploited. There is the familiar light organ that
transforms sound to either fluctuations in LED bar graphs or
dynamic displays in Apple iTunes or Microsoft Media Player.
Computer-controlled haptics interfaces provide virtual screen
objects with realistic mass, elasticity, and momentum. Flight
attitude indicators supplement a pilot’s vestibular system by
showing attitude and an artificial horizon. As suggested by the
matrix, useful transformations can be performed within a
given sense, such as augmenting hearing by transforming high
frequency audio signals into signals within the normal range of
human hearing, or transforming infrared light to visible light.
One reason for the relatively few sensory transformations in
everyday use is the lack of appropriate sensors and transducers.
My latest focus in esoteric sensors is on the various light sensors
from Texas Advanced Opto-Electronic Solutions (TAOS,
www.taosinc.com) and Texas Instruments ( www.ti.com), including light-to-voltage and light-to-frequency chips and a variety of
color sensors. Light-to-frequency chips convert light intensity to
a microcontroller-compatible pulse train with a frequency
proportional to light intensity. With a microprocessor on the
sensor output, light intensity can be easily converted to sound,
color shift, smell, or pressure, given an appropriate transducer.
Another reason for the lack of sensory transformations is the
difficulty in determining what is practical and useful in everyday
life. One area of active research and development is medicine.
Consider a diabetic with the inability to detect pain in his feet
because of the loss of sensation (diabetic neuropathy). Because
of this loss of sensation, diabetics often neglect sores, cuts, and
bruises on their feet, resulting in infections and, in some cases,
gangrene. However, pressure sensors in the shoes or shoe inserts
of a diabetic could transform a sudden pressure gradient — ordinarily perceived as pain — into a prick or modest electric shock
on the leg, an audible alarm, a flashing light, or even an odor.
Study the matrix in Table 1, devise your own applications,
and then dive in with the appropriate sensors, transducers, and
microcontrollers. And don’t be constrained by the matrix — many
useful assistive devices add new senses. For example, a talking
compass or GPS provides direction and location information that
a normal person can’t determine from his innate senses.
If you’d like a ready source of inspiration, google “synesthesia.”
People with this condition experience sensations seemingly unrelated to the initial stimulus. For example, a particular sound may evoke
the visualization of a color — akin to a built-in light organ. NV