The two most popular types of non-contacting joystick technologies are induction and Hall effect. Both offer highly reliable output at reasonable costs. In addition, the gear train used to drive potentiometers is eliminated, enhancing the reliability of the joystick even more. Inductive joysticks work on the principle of varying an induced field in a set of secondary coils by changing the relative position of a primary coil or ferrous shaft to the secondary coils. Protection from outside electrical fields is provided by an internal detection system. The size and number of coils limit how small these joysticks can be practically manufactured.

Hall-effect joysticks operate on the principle of varying voltage output by disturbing a current flow through interjection of a magnetic field. An advantage of Hall-effect technology over inductive technology is miniaturization of the output device and redundancy at a very modest cost. When properly designed and packaged, Hall-effect devices offer very high resistance to electromagnetic and radio frequency interference. Because the increase in reliability comes at little-to-no increase in cost, these joysticks can be used in all of the applications where the more-traditional potentiometertype joysticks fit.

Continuing evolution

As equipment or vehicle operator cabs has become more sophisticated and ergonomic, electric joysticks have evolved even further with the adaptation of a variety of hand grips to them. Providing an operator the ability to perform multiple tasks by manipulating a variety of switches on a handgrip coupled to the input shaft of the joystick is a means of significantly increasing productivity. By using grip-mounted switches to accomplish high-frequency tasks, equipment operators no longer must avert their attention or reposition their body to activate a switch that previously was difficult to reach.

Electric joysticks are specifically designed with hollow input shafts to provide wire routing from the handgrip down through the joystick. Joysticks are manufactured as single, dual or 3-axis control ( X, Y and twist). The handgrip can provide a platform for additional proportional axes by installing a thumb wheel pot, analog rocker or thumb-operated miniature joystick.

With the wide variety of joysticks available, there is sure to be at least one for virtually any application. A discussion of your specific application with the joystick manufacturer will ensure the best joystick choice. Find a company that manufactures a full range of joysticks and is willing to spend the time to suggest a solution.

Joystick categories

Large, hand controls Small, finger-operated
Displacement Force Displacement Force
Discrete Proportional Proportional Discrete Proportional Proportional
Switch Potentiometer
Encoder
RVDT
Inductive
Hall effect
Inductive
Strain gauge
LVDT
Switch Potentiometer
Hall effect
Inductive
Thick film
Strain gage

For more information, contact the author at (800) 333-5762, email glarocque@jrmerritt.com, or visit www.jrmerritt.com.