Among a huge variety of plastic components manufactured for the automotive industry, there is a vast set of buttons, each of which is normally composed of 52 parts coupled to rubbers, metal parts, and electrically conductive connections that, altogether, allow an electrical control signal to be sent to the ECU to activate the desired functionality (e.g., opening a door window).
The present work proposes the replacement of this type of components by a single part, also made using injectable plastic, coupled with low-cost touch electronics. For this purpose, the sensitivity of a high set of touch, matrix and multifunction sensors (with particular focus on capacitive type sensors) was investigated, which, tightly coupled with the injected plastic, allow highly sensitive human touch detection and thus the corresponding control or functionality activation. A study of the integration of sensors in the plastic injection process (subject to high pressures and temperatures) is carried out and subsequently verified its correct operating functionality. This work also analyzes the communication protocol between the new touch sensor and the control unit (ECU) and demonstrates its implementation and correct operation controlling door windows and rear mirrors in a real utility vehicle tested in a factory environment.
The proposed solution allows the creation of more appealing touch designs, compared to current discrete integrated component approaches, and enhances the reduction of its environmental impact throughout the life cycle, the reduction of materials and resources used, and the reduction of weight and its effect on emissions and the autonomy of electric vehicles and, finally, the recyclability of the final product, thus contributing to the development of more sustainable industrial solutions in the automotive industry.