Sleep tracking with a self-powered smart pillow
The human body needs sleep as much as food and water. Yet many people don’t get enough of it, which hurts both mind and body. People who have trouble closing their eyes could benefit from sleep monitoring, but they have limited options for doing so. In a new study in Applied materials and ACS interfacesone team describes a potential solution: a self-powered smart pillow that tracks head position.
Studies have linked chronic lack of sleep to physical illnesses, such as diabetes and heart disease, as well as mental health issues. Those who wish to better understand what is happening to them at night have two main options. They can take a sleep test done at a medical facility, or they can use an app through a smartphone or smartwatch — a much more convenient, but less accurate, choice. Recognizing the need, many groups have begun to develop new sleep monitoring systems using triboelectric nanogenerators (TENGs). These self-powered systems have taken the form of eye masks, belts, patches, and even sheets. Ding Li, Zhong Lin Wang and their colleagues wanted to adapt this approach to create a less restrictive, more comfortable version that focuses on head movement during sleep.
To build this new smart pillow, the researchers formulated a soft, porous polymer triboelectric layer. Movement between the head and this layer changes the electric field around nearby electrodes, generating a current. They linked several of these self-powered sensors to create a flexible and breathable TENG (FB-TENG) network that can be placed on a regular pillow. This system could generate a voltage corresponding to the amount of pressure applied, and it could follow the movement of a finger tracing letters. The FB-TENG could also capture the pressure distribution of a human headform as it changed position. According to the researchers, this smart pillow could have uses other than sleep tracking. For example, the system could monitor patients with diseases that affect head movement, such as cervical spondylosis, a degenerative neck disorder. Additionally, the smart pillow could be adapted to offer an early warning system for people at risk of falling out of bed, they say.
The authors acknowledge funding from the National Key Research & Development Project of the Ministry of Science and Technology of the People’s Republic of China and the National Natural Science Foundation of China.