Light is an essential element of building design that influences human health, comfort, performance, and well-being. Humans' daily rhythms in behavior and physiology, such as wake/sleep patterns, have evolved under natural light-dark cycles over millions of years. Nowadays, as we spend a large proportion of our time in the built environment, we are exposed to less light during daytime hours and more light during nighttime hours than what we would have naturally received across day and night. Thus, inappropriate and insufficient personal light exposure during the day and night can negatively affect this standard rhythm and is associated with a range of psychological, physical, and mental health issues. While most lighting design recommendations and standards have been limited to addressing the energy and visual aspects of light, this trend has been criticized, and current standards acknowledge the link between light and human health. Moreover, lack of low-cost and reliable tool to track and monitor the characteristics of light exposure as a stimulus that affects the human circadian system is evident.
This dissertation proposed a novel user-centric lighting assist tool consisting of a low-cost and wearable spectrometer to measure light spectrum and an interactive dashboard to visualize the collected data in meaningful and easy to understand quantities. Three studies covering the proposed tool are presented to 1) develop a low-cost and wearable spectrometer using Artificial Neural Networks (ANNs); 2) examine practical applicability of wearable spectrometer in the real-world environment ; and 3) develop and test the usability of an interactive dashboard for continuous tracking of personal lighting conditions. The first study examines the performance, accuracy, and fabrication challenges of developing a low-cost, wearable and wireless spectrometer to measure Spectral Power Distributions (SPD) of light sources using ANNs. Neural network was identified as an effective method for improving the accuracy of the developed spectrometer. Additionally, the developed spectrometer offers real-time communication that enables it to be integrated into IoT-based intelligent lighting systems for tailoring indoor lighting systems according to individual circadian needs. The second study examines the practical applicability of developed spectrometer to continuously record personal lighting conditions of office workers in real-world environment. The study provides insights for enhancing occupants health and well-being within the built environment. The third study examines the potential of a web-based app to enable healthier living with light. By engaging the end-user directly throughout the entire process of design and development of the interactive dashboard, the study identified the interactive dashboard as a useful and usable tool for end-users.
This dissertation is one of the first attempts to develop a low-cost and wearable spectrometer together with an interactive application to provide vital information regarding the non-visual effects of light on health by real-time tracking of personal lighting conditions. The findings of this dissertation demonstrates the importance of an affordable and accessible human-centric lighting assist tool as a powerful driver of promoting healthy behavior change in buildings, outlining new directions in the design of buildings that are not only comfortable and energy efficient, but also healthier for their occupants.