The JoyMouse Network — A NeatTools Application

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Introduction

The NeatTools Joy-Mouse data flow network shown in user-mode and developer-mode allows precise positioning of the mouse cursor under control of a joystick. This can be either a standard computer joystick, or a custom one (e.g. small chin joystick for a quadriplegic) that delivers XY signals to analog inputs of an computer interface module such as TNG-3. The network manages two subsidiary inputs for control of the left mouse click and a keypress (e.g. backspace). This can be edited easily to accommodate another key or else right mouse click. Additional controls can be added as needed. The current network uses only 4 of the 16 available inputs (8 analog and 8 digital) of TNG-3. .

The mouse cursor can still be controlled by the computer mouse and related pointing devices (trackball, touchpad, etc.). This complex network exploits many of the sophisticated features of NeatTools (e.g. Multiplexers, Demultiplexers, Decoder, ClockDivider). In the linear mode (proportional-control), the mouse cursor speed increases in direct proportion to joystick deflection (once beyond a free-play zone that can be set by the user). The adjustable nonlinear profiles in the quadratic and cubic modes provide precise control of the cursor for small joystick deflections, while allowing rapid movement for large deflections. After calibration and/or adjustment, the joy-mouse network can be in the background or minimized when in operation. If the user needs to return to it, the <alt><tab> key sequence can be used to restore the joy-mouse NeatTools window in focus; this will disable cursor motion by the joy-mouse and allow the user to turn Enable off (see below).

Operation

The controls are as follows:

• There is an overall Enable switch (left center).Only when this switch is on (and the NeatTools/JoyMouse window is not in focus) will the mouse cursor respond to the joystick.
• The Joystick Type switch (lower left) selects computer or custom type of joystick as indicated by either of the red LEDs.
• When the custom joystick is used, it should be calibrated for full scale (both extremes for each of x and y) by temporarily enabling the Calibrate button (wider button below Enable button). Then, with the joystick at rest, press the momentary Sample-Hold button.

• For a custom joystick, the Button/Key Source switch (lower right) selects whether mouse button(s) and/or keyboard keys are activated by analog or digital inputs of TNG-3 (for TNG-2, only analog inputs are available).
• For a computer joystick, which has its own buttons, the Button/Key Source switch should be set to analog (because, when there are no switches connected to the digital inputs of TNG-3, the button/key states will be asserted by default, thus interfering with system operation). This coupled switch setting is done automatically when one sets Joystick Type to computer. However, this action can be (inadvertently) overridden by subsequent actuation of the Button/Key Source switch. So beware.
• The Button/Key Mode switch selects whether the mouse button(s) should be operated in single-click (Stroke/Click) or drag (Depress) mode when the signal is asserted. Normally it is best to leave this in Depress mode. (Note that the nomenclature still reflects the original intention of enabling autorepeat of keys that are kept depressed. This is not achievable by use the depress input of NeatTools key objects. Rather, pulse/timer objects would have to be included. This feature will be added only if a need arises.)
• The Resolution slider at top left controls the number of steps to be resolved from the joystick signal (horizontal or vertical) after calibration. This also affects the "gain" (see below), i.e. how fast the cursor will respond. One should first try the higher range (such as the maximum value of 32).
• The Free Play Limit Value slider delimits a range of joystick deflection that will produce no mouse cursor motion. This feature is to ensure that the mouse cursor remains stationary when the joystick is at or near the nominal rest position.
• The Profile pushbutton (upper right) selects any one of three relationships for mouse cursor velocity as a function of joystick deflection (in either horizontal or vertical dimensions on computer display): Linear, Quadratic, or Cubic. Note that the quadratic function (parabola) must be inverted (flipped) from the second to the third quadrant (i.e. mouse velocity must be negative for negative joystick deflections). Further, the functions are all displaced away from the origin according to the width of the joystick free-play zone.
• The slider pairs in the Quadratic and Cubic sections just below the Profile section determine the coefficients (actually reciprocals thereof) for the quadratic and cubic functions. The value shown in the large integer-display objects is determined as the product of the two integer values set by the sliders. This arrangement is designed to that multiples of the value of one slider can be incremented according to the value of the other slider in each pair.
• Higher values lead to weaker mouse-cursor response (lower gain) for a given joystick deflection. The choice of these parameters depends on display resolution, (disabled) user needs, type of application to be controlled by mouse, etc.