A multi-dimensional matrix keyboard interfacing circuit design

Abstract

Purpose

This paper presents a novel design method for keyboard circuits. The purpose of this study is to enable a single-board computer with fewer pins to recognize a keyboard system consisting of a large number of switches. Through the study of different kinds of keyboard circuits, a general circuit schematic design method is abstracted. Several experiments are conducted to prove the feasibility of the proposed circuit design method.

Design/methodology/approach

Conventional circuit schematic diagrams are often limited to two-dimensional planes. Through investigating higher dimensional alternatives, this paper proposes to place components in high-dimensional geometry before connecting all components. A multi-pin switch construction method is proposed to allow the switches to be arranged on the vertices of high-dimensional geometry and be connected sequentially to form the keyboard system. This proposed system can allow a keyboard system consisting of a large number of switches to be recognized by a single-board computer with less available pins.

Findings

The design scheme proposed in this paper can read more switch states with limited Input/Output pins. With the increase of the number of Input/Output ports and pins, the number of simultaneously identifiable switches increases exponentially, which is suitable for sensor design of array type.

Research limitations/implications

Compared with the classical keyboard circuits, the circuit designed using the proposed method will lead to a slightly longer recognition time for each key. This can be compensated by a single-board computer with a modestly higher clock speed.

Originality/value

The circuit schematic design method based on high-dimensional geometry is introduced for the first time. The feasibility of the proposed method is verified by the original experiments. The proposed approach is of importance in guiding the design of new analog and digital sensor circuit systems.

Citation

Yu, G., Yao, Y. and Song, Z. (2020), "A multi-dimensional matrix keyboard interfacing circuit design", Circuit World, Vol. 46 No. 3, pp. 175-182. https://doi.org/10.1108/CW-10-2019-0142