Development of an automatic system for the measurement of force and stroke parameters of car radio keypads

Keypads are basic components used in Human Machine Interfaces designed for electronic devices. Different shapes and force-stroke parameters are used in the respective design covering a large range of applications. Bosch Car Multimedia is a huge manufacturer of car radio and navigation systems worldwide. Most Bosch Car Multimedia products have one or more keys and the important design parameters for these keypad elements are forces and strokes usually described as force versus stroke diagram with some kind of hysteresis. Keys usually have small values of force and stroke, and these low values require a measurement system with high precision and high repeatability. This paper presents a mechatronic system developed in the described context. With this system the company is better equipped to fulfil customer specifications.