Toward Green and Flexible Human-Machine Interfaces: Personalized DIY Paper-Based Capacitive Macro Touchpads

Plastic-based Human-Machine Interfaces (HMIs) offer convenience and affordability, but they often lack the customization options needed to cater to diverse user needs. In contrast, macro keypads and touchpads are gaining popularity due to their ability to be customized for specific tasks, form factor, software integration, and adaptability to various digital tasks, such as gaming, content creation, and productivity tasks. Due to their non-biodegradability and short serviceable lifespan, portable electronics and HMIs have significantly contributed to electronic waste (e-waste), with projections indicating that e-waste production will reach 110 million tonnes by 2050. To address these waste issues, green HMIs are needed that can be customized for various digital applications and have a minimal environmental footprint. This paper presents green paper-based capacitive macro (PCM) touchpads, customizable for various digital applications. The PCM touchpad's form factor can be tailored to specific needs, and its functionality can be personalized both digitally and through physical customization. The PCM touchpads, equipped with capacitive touch sensors, serve as versatile HMI, enabling seamless interaction with various digital applications on mobile devices and laptops. The PCM touchpads are manufactured using a simple, solvent-free, and environmentally friendly technique that involves directly cutting and pasting readily available materials onto a flexible paper substrate. This allows for easy customization and personalization of PCM touchpads for various applications within home settings, as required materials, such as paper, copper tape, and microcontrollers, are readily accessible. The PCM touchpads, made from biodegradable materials such as paper, can be easily disposed of, reused, recycled or repurposed, reducing their environmental impact. The performance of the PCM touchpad was evaluated by customizing it for a variety of digital applications, including a miniature game console, smartphone control, PC conferencing application control, and PC game control. PCM touchpads, customizable for various digital applications, even in home settings, offer a sustainable solution. As green HMIs, they contribute to the circular economy by reducing electronic and plastic waste. This aligns with the Sustainable Development Goals of the United Nations, which promote responsible and environmentally conscious production practices.