Vector electronic control device

• US 4,694,279 A
• Filed: 10/17/1986
• Issued: 09/15/1987
• Est. Priority Date: 10/17/1986
• Status: Expired due to Fees

• Current Assignee: University Of Pittsburgh (University of Pittsburgh of The Commonwealth System of Higher Education)
• Original Assignee: University Of Pittsburgh (University of Pittsburgh of The Commonwealth System of Higher Education)
• Inventors: Meno, Frank
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Blum, Richard K.
• Application Number:
  US06/920,123
• Time in Patent Office: 333 Days
• Field of Search: 273/85 F, 273/85 G, 307/116, 318/662, 324/60 C, 328/5, 340/347 P, 340/347 DA, 340/347 AD, 340/365 C
• US Class Current: 341/6
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

An electronic control device for providing control signals having direction and magnitude represented by electrical output signals based upon employing a circuit that senses relative changes in capacitance with a few volt excitation at suitable frequency. A finger touch unbalances the equilibrium between a pair of capacitance electrodes which by means of the circuitry selectively produces signals representative of magnitude and direction, and whose rate is proportional to the degree of unbalance, and which signals are used for vector control purposes. The electrodes are positioned in a recessed slot in an encasement, which slot is accessible by fingers, and which pair of capacitance electrodes is protected by a dielectric layer.

Claims

1. In an electronic device for generating at least two interrelated electrical outputs, comprising:

at least two capacitive sensing means each for establishing a capacitor with a grounded electrical conductor positionable to conduct a capacitance when said conductor contacts said sensing means, and said sensing means having a configuration such that its capacitance changes as the position of said grounded conductor changes;

a first generating means for generating a first electrical output of selected characteristics and strength in response to said change in capacitance imposed upon one or both of said sensing means including a difference determining means for deriving the difference in capacitance between said two sensing means, and said first electrical output representing this difference and defining the direction of the displacement of said grounded conductor on one or both of said sensing means; and

a second generating means for generating a second electrical output of selected characteristics and strength in a response to said change in capacitance imposed upon one or both of said sensing means, including a deriving and amplifying means for deriving and amplifying the difference in capacitance between said two sensing means; and

rectifying means for receiving said second electrical output and for generating a third electrical output defining the magnitude of said displacement of said grounded conductor on said one or both sensing means, whereby upon relative positioning and movement of said grounded member, the direction and magnitude of said output signals may be established.

2. In a device of claim 1, including first converting means for receiving and converting said third electrical output into a digital output signal.

3. In a device of claim 1, including second converting means for receiving and converting said third electrical output into an analog output signal.

4. In a device of claim 1, inluding selective converting means for receiving and selectively converting said third electrical output into a digital output signal or an analog signal.

5. In a device of claim 1, wherein said two sensing means consists of a pair of cooperative electrodes, and further comprising:

a grounded encasement having recessed slot means located in a top surface thereof; and

wherein said two sensing means consist of a pair of cooperative electrodes, each arranged in said slot means and a dielectric layer substantially covering said electrodes, whereby said grounded conductor has access for contact with said dielectric layer through said slot means.

6. In a device of claim 5, including said electrodes having a configuration such that displacement of said grounded conductor over said dielectric layer changes the capacitance of said electrodes.

7. In a device of claim 5 including saod electrodes being generally triangular in plan and arranged along a longitudinal axis of said encasement in said slot means so that displacement of said grounded conductor over said dielectric layer changes the capacitance of said electrodes.

8. In a device of claim 5, including electronic circuit means comprising at least said first and second generating means and said rectifying means;

and

said encasement having means for carrying said electronic circuit, and includes means for electrically insulating and separating said electronic circuit from said electrodes.

9. In a device of claim 1, including said first generating means consisting of a first and second equivalent operational amplifier means, each for detecting the change in the capacitance of its associated sensing means, and each said amplifier having an AC gain.

10. In a device of claim 9, including a third operational amplifier means for receiving and comparing said AC gain signals of said first and second operational amplifier means and producing said first electrical output for said definition of said direction.

11. In a device of claim 9, including said two sensing means being an electrode designated as C₁, C₂ and first and second amplifier means associated with a different one of said electrodes, and each consisting of a capacitor C₃, C₄, respectively, and a resistor R₂, R₃, respectively, whereby said AC gain signal of said first amplifier is controlled by the equation:

space="preserve" listing-type="equation">[1+C.sub.1 /(C.sub.3 -j/2π

f R.sub.3)]

where j=√

-1 and f is the frequency in said device, and said amplifier is controlled by the equation;

space="preserve" listing-type="equation">[1+C.sub.2 /(C.sub.4 -j/2π

f R.sub.2)]

where j=√

-1 and f is the frequency in said device.

12. In a device of claim 10, including said two sensing means being an electrode designated as C₁ and C₂ respectively and said first and second amplifier means associated with a different one of said electrodes, and consisting of a capacitor C₃ and C₄ respectively, whereby said AC gain signal of said third operational amplifier means is controlled by the equation