How Does a Potentiometer Work in Ruggedized Joysticks?

Joysticks have far-reaching applications. They are today used in almost all fields including aircraft controls and other heavy machinery control in a variety of industries. Simply put, ruggedized joysticks work as control input devices. However, to get a better understanding of how these devices work, you must first understand how the potentiometer (the sensor) works.

Put simply, ruggedized joysticks are input devices. They are made up of a stick (lever) that pivots on a base. When you move the stick, a message is relayed to the device that is being controlled. This results in a corresponding movement. However, this is not possible without a sensor that converts the analog input into digital output. The most commonly used sensor is the potentiometer.

In earlier joysticks, the joystick was connected directly to cables and rods that were connected to the ailerons and elevator. Today, joysticks are more sophisticated. The devices integrate into fly-by-wire systems which convert a joystick input into an electrical signal for the control surfaces. This means the joystick doesn’t have any physical rods or cables. Modern joysticks thus convert mechanic inputs into electrical signals with the help of a potentiometer.

A potentiometer is a manually-adjustable three-terminal resistor. The resistor has a rotating or sliding contact which forms an adjustable voltage divider. The work of this sensor is to measure the electromotive force by balancing it against the potential difference that is produced by passing a known current through the known variable resistance. Potentiometers fall into one of two categories: rotary and linear.

If a joystick has multiple axes, this means the joystick will have multiple sensors that sit below the shaft. The circuit is normally connected to contact terminals. The contact terminals allow electrical signals to be sent to the processing unit.

With industrial joysticks, the potentiometer is connected to each of the joystick shafts. In this way, pivoting the shaft will rotate the contact arm. The potentiometer will produce a corresponding turn when the stick is moved. The varying resistance of the potentiometer is what alters the electrical current in the circuit. The potentiometer will thus translate the physical position of the stick into an electrical signal. The electrical signal is then passed to the joystick port and onto the computer. The computer will then translate the analog electrical signal and convert it into a digital signal that is communicated to the hardware being controlled.

The quality of a joystick is measured by how seamlessly the physical input is converted into an electrical signal. A smooth translation is a result of good joystick design and integration.

Ruggedized Joysticks