Standardization of Light Emitting Diode Feedback on Metered Solar Home Systems

Abstract

Light Emitting Diodes (LEDs) are used in a variety of devices ranging from watches to solar home systems, as status indicators or communicative tools. They are typically designed to produce light in different colors and intensities. However, the communicative output varies across devices of similar or different functions. This variation and the sense that there is a wide array of expressions that can be employed, makes it hard for users of the devices to deduce the feedback easily. To address this gap, this paper discusses the effectiveness of a standardized light-based interface for metered solar home systems, which has been redesigned using a structured Human Computer Interaction (HCI) design process. The study makes use of the UFuRT (User, Function, Representation and Task analyses) framework to evaluate the use of these devices ethnographically and contextually among solar home-system owners in the Rift Valley region of Kenya. To understand how solar home systems users utilize multicommunicative LEDs, 111 solar home system owners participated in in-person interviews. The results indicate that, on average, 51% of solar-home system owners cannot correctly interpret or do not know the LED feedback of the device they own. The quantitative and qualitative data collected from the in-person sessions was used to design a simulated standardized interface of a metered solar home system. The effectiveness of this newly designed interface was measured by interviewing another set of 43 solar home system users. The results indicate that, on average, up to 63% of solar system owners correctly interpret the LED feedback mechanisms of a standardized design. Further, up to 86% of solar system owners correctly interpret specific feedback mechanisms of a standardized design. With these findings, the study concludes that using a HCI framework to standardize the interface design of LED-touting devices increases the expressivity and user understanding of feedback relayed by these devices. Thus, manufacturers and industry governing bodies need to consider a universal vocabulary of light-based design that can be widely adopted to solve device usage challenges.