“…These sleep tracking systems include technologies that remotely measure physiological signals from the user, without direct body contact, such as smart home sensors (e.g., Google Nest hub 2) and undermattress sleep trackers (e.g., the Withings Sleep Analyzer). Additionally, many sleep-tracking systems are in the form of wearable or portable systems capable of collecting signals, such as actigraphy wristbands (e.g., Ancoli-Israel et al, 2003;Lichstein et al, 2006;Martin & Hakim, 2011;Morgenthaler et al, 2007;Sadeh, 2011), smartwatches (e.g., Alfeo et al, 2018;Chang et al, 2018;De Zambotti et al, 2018;Phan et al, 2015;Sun et al, 2017), smart rings (Altini & Kinnunen, 2021;Chaudhry et al, 2020;Malakhatka et al, 2021;Mehrabadi et al, 2020;Koskimäki et al, 2018), and EEG-based systems such as headbands (Arnal et al, 2020;Koushik et al, 2019;Mota-Rolim et al, 2019;Onton et al, 2016).…”