Self-powering smart pillow tracks your head during sleep

Studies have linked chronic lack of sleep to physical ailments, such as diabetes and heart disease, as well as mental health issues.

People who struggle to sleep can either take a sleep test, or they can use an app through a smartphone or smart watch – a much more convenient, but less accurate choice.

Recognising the need, many people have begun developing new sleep monitoring systems using triboelectric nanogenerators (TENGs). These self-powering systems have taken the form of eye masks, belts, patches and even bed sheets.

In a new study in ACS Applied Materials & Interfaces, Ding Li, Zhong Lin Wang and their colleagues describe how they wanted to adapt this approach to create a less restrictive, more comfortable version that focuses on the movement of the head during sleep.

To construct this new smart pillow, the researchers formulated a flexible, porous polymer triboelectric layer. Movement between the head and this layer changes the electric field around nearby electrodes, generating a current.

They strung together several of these self-powering sensors to create a flexible and breathable TENG (FB-TENG) array that can be placed atop an ordinary pillow. This system could generate voltage that corresponded to the amount of applied pressure, and it could track the movement of a finger tracing out letters. The FB-TENG also could capture the pressure distribution of a fake human head as it shifted position.

This smart pillow could have uses beyond tracking sleep, the researchers say. For example, the system could monitor patients with diseases that affect the movement of the head, such as the degenerative neck disorder cervical spondylosis. What’s more, the smart pillow could be adapted to offer an early warning system for those at risk of falling out of bed, they say.