The Inductive Touch System Design Guide presents an overview of the typical sensor mechanical structure and sensor electrical design for human machine interface (HMI) button applications. The mechanical design chapter discusses several factors that impact button sensitivity, including metal selection, sensor geometry, sensitivity dependence on target-to-coil distance, and mechanical isolations. Two options of common layer stacks for inductive touch buttons are also presented. The sensor design chapter focuses on flex PCB sensor electrical requirements and considerations for optimal sensitivity.
Implementing an effective inductive touch solution requires appropriate system mechanical design and matching sensor design. The mechanical design should take into consideration the material properties, button geometry, and sensor construction and mounting. The following sections will address each of these topics.