Pointing stick having chip resistors

Abstract

A device for generating conditioned electrical signals in response to forces applied to the device. The device includes a shaft attached to a substrate. Several strain sensitive resistors are mounted on the substrate around the shaft for generating an electrical signal representative of a magnitude and direction of force applied to the shaft by a user. Several apertures are in the substrate, each aperture is located between a pair of strain sensitive resistors. The apertures concentrate the stress on the resistors. A signal conditioning device is mounted to the substrate and is electrically connected to the resistors for conditioning the electrical signal. The signal conditioning device receives the electrical signal in an analog form and provides a conditioned signal as an output in a digital form. The device is mounted to a keyboard base. An alternative embodiment is shown using a cavity instead of apertures in the substrate.

What is claimed is:  
     
         1 . A pointing device for generating an electrical signal, comprising: 
 a) a shaft, having a first and second end;    b) a substrate having the first end of the shaft attached thereto;    c) a plurality of strain sensitive resistors, mounted on the substrate around the first end, for generating an electrical signal representative of a magnitude and direction of force applied to the shaft by a user; and    d) a plurality of apertures extending through the substrate, each aperture located adjacent at least one of the strain sensitive resistors.    
     
     
         2 . The device according to  claim 1 , wherein at least one circuit line is disposed on the substrate and is electrically connected to the resistors.  
     
     
         3 . The device according to  claim 1 , wherein the substrate has a bore passing therethrough, the first end of the shaft being mounted in the substrate bore.  
     
     
         4 . The device according to  claim 1 , wherein the device is attached to a mounting bracket that is adapted for connection with a keyboard base.  
     
     
         5 . The device according to  claim 1 , wherein the keyboard base has an aperture and the second end of the shaft extends through the keyboard aperture.  
     
     
         6 . The device according to  claim 1 , wherein a signal conditioning circuit is mounted on the substrate and is electrically connected to the resistors for conditioning the electrical signal, the signal conditioning circuit being adapted to receive the electrical signal as an input and provide a conditioned signal as an output.  
     
     
         7 . The device according to  claim 1 , wherein a plurality of terminals are mounted on the substrate and are electrically connected to the resistors.  
     
     
         8 . A device for generating electrical signals in response to forces applied thereon by an operator, the device operable to be connected to an external circuit, comprising: 
 a) a shaft, having a first and second end;    b) a substrate having the first end of the shaft attached thereto;    c) a plurality of strain sensitive resistors affixed on the substrate, the resistors disposed around the shaft, the strain sensitive resistors operable to generate an electrical signal representative of a magnitude and direction of force applied to the shaft by the operator; and    d) a plurality of apertures passing through the substrate, each aperture located beside one of the resistors.    
     
     
         9 . The device according to  claim 8 , wherein a signal conditioning circuit is mounted to the substrate and is electrically connected to the resistors, the signal conditioning circuit adapted to receive the electrical signal as an input an provide a conditioned signal as an output.  
     
     
         10 . The device according to  claim 9 , wherein the substrate is a printed circuit board.  
     
     
         11 . The device according to  claim 10 , wherein at least one circuit line is located on the printed circuit board and is connected to the resistors.  
     
     
         12 . The device according to  claim 11 , wherein a terminal is located on the printed circuit board and is connected to the circuit line.  
     
     
         13 . The device according to  claim 12 , wherein the substrate has a cavity disposed on a second substrate surface and the resistors are disposed on a first substrate surface such that each resistor is partially disposed above the cavity.  
     
     
         14 . An electronic control device for allowing a user to control the movement or operation of a responsive electronic system, comprising: 
 a) a shaft having a first and second end;    b) a substrate having four apertures extending therethrough, the second end of the shaft attached to the substrate;    c) four strain sensitive resistors mounted to the substrate, each resistor being located adjacent one of the apertures; and    d) a plurality of circuit lines connecting the four strain sensitive resistors into a bridge circuit that is adapted to generate an electrical signal representative of a direction of mechanical force applied to the shaft by the user.    
     
     
         15 . The device according to  claim 14 , wherein a signal conditioning circuit is mounted to the substrate and is electrically connected to the bridge circuit, the signal conditioning circuit adapted to receive the electrical signal as an input an provide a conditioned signal as an output.  
     
     
         16 . The device according to  claim 14 , wherein the substrate is a printed circuit board.  
     
     
         17 . The device according to  claim 16 , wherein a terminal is located on the printed circuit board and is connected to the circuit line.  
     
     
         18 . The device according to  claim 16 , wherein the substrate has a first and second side.  
     
     
         19 . The device according to  claim 18 , wherein the second end of the shaft is attached to the first side and the resistors are attached to the second side.  
     
     
         20 . The device according to  claim 18 , wherein the second end of the shaft is attached to the first side and the resistors are attached to the first side.