Mouth-operated control device

A light-sensitive device is placed so as to receive a portion of the ambient light energy present within the mouth of the operator. The amount of ambient light impinging upon the sensing device is then modulated by movement of the lips and teeth of the operator, controlling some external process.

FIELD OF THE INVENTION 
The present invention relates to general-purpose control devices which 
translate some type of bodily motion into corresponding variations in 
electrical signals or parameters, specifically motions of the mouth. 
BACKGROUND OF THE INVENTION 
A variety of devices are known for translating bodily movements of one kind 
or another into variations in electrical signals or parameters. The most 
common of these are manually-operated rotary and linear potentiometers, 
manipulated by the hand(s) of the operator. While this is in many cases 
satisfactory, in some instances the hands of the operator are unavailable 
for these tasks, as in the case of a musician, both of whose hands may be 
occupied in the manipulation of an instrument. To circumvent this problem, 
control devices have been mounted in pedals for manipulation by the feet. 
This often proves clumsy in practice, as foot dexterity in most persons is 
less developed than manual dexterity. There are also instances where both 
the hands and the feet of the operator are unavailable, as in the case of 
musicians playing instruments which require both hand and foot operation, 
the case of disabled persons who have lost the use of hands and feet, and 
the case of persons operating complex machinery requiring the use of hands 
and feet. 
There exist in the art several devices which sense eye movements and/or 
blinking. U.S. Pat. No. 3,379,885 by C. L. Nork and U.S. Pat. No. 
4,081,623 by A. W. Vogeley illustrate two such devices. These are 
generally awkward and obtrusive in use, requiring a head-mounted apparatus 
aimed at the eye(s). They are often binary in nature, generating only 
pulse-type signals indicating only that an eye movement has or has not 
occurred. Furthermore, they are relatively costly, precluding their use in 
general, consumer-oriented products. 
Several types of mouth-operated devices are also in common use, 
particularly in the field of electronic musical instrument control. One 
type requires the operator to blow or suck on a hollow tube, causing a 
flow of air or a pressure variation which is sensed electronically. 
Another type requires the operator to "bite", with varying intensity, on a 
pressure-sensitive device. These mouth-operated devices overcome the 
limitations of the manual, pedal, and ocular devices previously mentioned, 
but all involve relatively expensive and/or "exotic" technology. In 
certain cases, particularly the control of resonant filters in spectral 
shaping of electronic musical instruments, their particular mode of 
operation may lack "naturalness", due to a lack of correspondence between 
the mouth movements of the operator and the resultant "vocal" qualities of 
the filtered instrument. 
Control by spoken sounds is also well-known, however, simple, inexpensive 
sound-operated devices are generally limited to binary, on-off type 
operation. More elaborate speech-operated devices are available in the 
form of computerized speech-recognition systems which can distinguish 
between various spoken words, but these are costly, problematic in 
high-noise environments, and provide discontinuous control functions, i.e. 
separate on-off outputs for each recognized utterance. Another type of 
voice-activated controller is the vocoder, which can superimpose the 
spectral weighting of spoken utterances onto an instrument's sound. 
Vocoders are well-suited to tonal modification of electronc musical 
instruments, but are complex and costly, and are not general-purpose 
control devices. 
SUMMARY OF THE INVENTION 
It is the object of the invention to provide a means of control by movement 
of the mouth. 
It is a further object of the invention to provide such a means of control 
whereby continuously variable control may be achieved, rather than 
discrete, on-off control, if so desired. 
It is a further object of the invention to provide such a means of control 
which, when used to control frequency-selective filters acting upon the 
output of electronic musical instruments, can afford a degree of 
correspondence between the operator's mouth movements and the resultant 
"vocal" quality of the filtered sound, i.e. the operator's facial 
expression will appear to be producing a vocalization similar to the sound 
being produced by the instrument. 
It is another object of the invention to provide such a means of control 
that may be fabricated from commonly available parts, is manufacturable at 
low cost, and which is highly commercial. 
These and many other objects and advantages of the present invention will 
be readily apparent to one skilled in the art to which the invention 
pertains from the claims and from the perusal of the following detailed 
description in connection with the appended drawings. 
In accordance with the aforementioned objects the present invention 
comprises a light-sensitive device whose electrical characteristics are 
dependent upon the amount of light impinging upon its surface, which is 
placed within or coupled optically to the interior of the mouth of the 
operator, who may then vary the amount of ambient light impinging on the 
sensor by opening and closing his or her mouth in varying degrees.

DRAWING REFERENCE NUMERALS 
1 Replaceable Mouthpiece 
2 Light-Sensitive Device 
3 Sensor Housing 
4 Wiring 
DETAILED DESCRIPTION OF THE INVENTION 
With reference to the cross-sectional view shown in FIG. 1, the preferred 
embodiment of the invention comprises a light-sensitive device 2 
encapsulated within a translucent housing 3, which protects it from 
moisture. The light-sensitive device may be any one of a number of such 
well-known and commonly available devices, including photo-conductive 
cells, silicon or other photovoltaic cells, and phototransistors. Wiring 4 
connects the sensor to whatever circuitry is to be controlled. In 
applications where wires are unacceptable, they may be replaced by 
suitable wireless transmission means, e.g. a radio control system. 
Replaceable mouthpiece 1, composed of translucent material, preferably 
soft, slips over the housing and is held by friction or other means. While 
the mouthpiece could be made integral with the housing, replaceability 
provides a measure of protection from disease transmission by allowing 
mouthpieces to be changed between operators. The shape of the embodiment 
as shown in cylindrical, but may be any shape, preferably one which is 
found to be comfortable and easily held in the mouth. 
OPERATION 
Referring to the pictorial views shown in FIGS. 2 and 3, the sensor or 
light transmissive means is positioned partly or entirely within the 
operator's mouth such that the amount of ambient light impinging upon the 
sensor may be varied by movements of the operator's lips and/or teeth. 
FIG. 2 shows the operator's mouth open, admitting ambient light, while 
FIG. 3 shows the operator's mouth closed, blocking ambient light. Coarse 
control of the sensor's response is achieved by varying the degree to 
which the device is inserted within the mouth of the operator. This 
adjustment can compensate to a large degree for variations in ambient 
light level, and in practice has been found to be made intuitively by the 
operator by manipulation of the teeth and lips to find the optimal 
operating point. While the simplest configuration as shown in the Figs. is 
one where the device is held by the teeth of the operator, the device may 
alternatively be held by any type of external stand or frame. With the 
device thus held, the operator need no longer hold his or her teeth 
clenched on the device, and the mouth may be opened to a greater degree 
for modulating the light falling on the sensor or for speaking or singing. 
Thus the reader will see that the mouth-operated control device of the 
invention provides a simple, low-cost, means of obtaining continuous 
control of an electrical parameter which may be used to control any 
external system. Furthermore, it can be seen that unlike previous 
mouth-controlled devices, the operator's mouth may open and close freely 
in the manipulation of the device, so that when the invention is used to 
control frequency-selective filters acting upon the output of musical 
instruments, the operator's facial expression can appear to be producing a 
vocalization similar to the sound being produced by the instrument. 
While the above description contains many specificities, these should not 
be construed as limitations on the scope of the invention, but rather as 
an exemplification of one preferred embodiment thereof. Many other 
variations are possible. For example, the housing and mouthpiece could be 
combined and formed as one piece; a radio transmitter could replace the 
wiring; the light-sensitive device could be remotely located from the 
operator's mouth and ambient light from the mouth conducted to the sensing 
device by light-transmissive means, e.g. fiber optic material; the 
invention could be combined with any of the prior art types of mouth 
sensors; the device could be made with an integral holder which would 
support it around the operator's head or neck, and so forth. Accordingly, 
the scope of the invention should be determined not by the embodiment 
illustrated, but by the appended claims and their legal equivalents.