1 System Description
Human-machine interfaces are a common part of many applications and typically require electro-mechanical
components for implementing buttons and dials. Many push buttons use a mechanical switch that has an
electrical contact that connects when the button is pressed. This interaction provides a point of wear and
tear that can breakdown overtime. Implementing buttons with switches like this also means having to seal the
button surface in applications that operate in harsher environments such as industrial or automotive applications.
Otherwise, this also allows for dirt or dust to get inside the mechanical button which can further reduce the
product lifetime.
Other HMI components like dials also suffer from wear and tear. Dials traditionally use an encoder or
potentiometer to determine the rotational change of the input. These components have mechanical components
that can breakdown over time similar to push buttons.
In this reference design, inductive sensing is used to implement seamless touch buttons that provide a contact
free implementation while also enabling variable force touch functionality. Additionally, hall-effect sensing is
used to implement a contactless dial to reduce the wear and tear that comes with devices like potentiometers
and rotary encoders. This design includes a 3D-printed housing that provides the button surface and rotational
push-button dial.
Since buttons and dials are a common component on many human-machine-interfaces, these technologies
can be used in a wide variety of applications. For automotive applications, inductive touch buttons provide a
force sensitive response that works with gloves on. Additionally, being able to design with a button on different
surfaces provides flexibility to the overall design. These same benefits also apply to other implementations such
as industrial HMI and appliances.
System Description
2
Inductive Touch and Magnetic Dial Contactless User Interface Reference
Design
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