Meet the joystick that’s also a rotary encoder
KEY TAKEAWAYS:
- The Series 293 delivers three forms of HMI in a single device
- Electromechanical solutions are evolving in response to manufacturers’ needs
- Experience in serving the high-reliability market ensures quality
User interaction is a constant in embedded design, but the way we implement human-machine interfaces is evolving. Technology like edge AI and voice recognition is ramping up. It promises an intuitive way to initiate or confirm simple tasks. But it still has limitations in almost every operating environment and currently lacks the accuracy or depth of control needed to operate complex equipment.
Medical devices, industrial controls and even many consumer products rely on precise user instruction, where multiple intents are communicated concurrently. Normally, control needs to be fast and decisive; emerging technologies, like large language models, simply can’t provide that today.
Engineers working on complex applications continue to choose trusted electromechanical solutions that avoid ambiguity but still offer flexibility. The go-to solutions today are not dissimilar to those of a decade ago. That indicates how important these technologies are, still. Incumbent technologies have been proven in the field, with some innovation but perhaps little evolution.
New solutions that combine genuine innovation with demonstrable evolution can make a real impact here. This is why the 3-in-1 joystick from CTS delivers. It combines three proven HMI modals in a single device that will feel instantly familiar yet distinctly modern.
Why a 3-in-1 joystick encoder?
Joysticks are widely used. They offer reliable and intuitive control, particularly when the actuation can be directly observed by the operator, who becomes part of the feedback loop.
Rotary switches provide a method for proportional control in a linear direction. Operators relate rotating a control directly to increasing or decreasing a parameter in predictable amounts.
Tactile switches provide the simplest form of activation, normally with some mechanical feedback that gives the operator assurance that a request has been initiated.
Each of these types of control mechanisms may be present in various types of equipment; in some, all three will be used in combination. For those applications, the Series 293 from CTS may be the solution.
The Series 293 combines all three into a single device. The joystick operates in the usual way, with X and Y axes, but it also adds a Z axis push-button. In addition, the joystick can be rotated to provide a variable input. All three functions work independently and simultaneously, making it unique in the market.
How does the Series 293 provide rotary encoding?
There are typically three ways to implement rotary encoding: a potentiometer, optically, or magnetically using the Hall effect. Rotary encoding based on potentiometer technology requires a physical electrical contact to a variable resistor, which comes with considerations related to wear and electrical noise. Optical encoders and Hall effect switches are non-contact technologies but with differing interface requirements.
The simplest non-contact encoding technology uses optical emitters and receivers, coupled to transistors, producing a digital signal that toggles as the switch rotates. This is how the Series 293 implements rotatory encoding.
The rotary position is encoded using two outputs, A and B. Both outputs toggle between high and low logic levels, depending on the angle of rotation. Each output will toggle four times per rotation, creating a pattern that repeats every 72 degrees. The A and B outputs are out of phase by 90 degrees, so there are four logic states per 72 degrees of rotation, meaning the smallest resolvable angle of rotation is 18 degrees. The direction can be inferred by which output leads a transition.
The electrical functionality of the Series 293 3-in-1 joystick encoder
Why did CTS develop the Series 293?
The Series 293 is a new product group for CTS, but it leverages the company’s experience in developing electromechanical devices such as tactile switches, as well as position sensing using potentiometers, encoders, and Hall effect switches.
The subcomponents of the Series 293 are already manufactured in-house by CTS, so developing an integrated solution was a natural extension. The 3-in-1 solution was originally developed in response to a customer's need to make medical devices. The device's tactile nature suits the application and the environment.
Since introducing the Series 293, CTS says it has also seen significant interest from the industrial sector, where requirements are similar but operating conditions differ. This may lead to variants of the Series 293 as standard products, but CTS points out that it can also develop customer-specific solutions based on the Series 293.
Conclusion
Many applications need a joystick, a rotary encoder and a push-button input. OEMs currently integrating all three of these control modals will find the Series 293 a welcome innovation. A single device offers three forms of control that can be software-defined to create any number of configurations. Avnet’s FAEs are on hand to help customers explore those possibilities.
Learn more about Avnet’s supplier partner, CTS. Download the CTS Series 293 3-in-1 joystick encoder datasheet from here: CTS Series 293 Joystick Encoder
