Tracking sleep with a self-powering smart pillow

Sleep is as important to the human body as food and water. Many people, however, do not receive enough, causing both mental and physical harm. People who have trouble sleeping might benefit from sleep monitoring, but they only have a few alternatives. One team offers a potential solution in ACS Applied Materials & Interfaces: a self-powered smart pillow that tracks the position of the head.

Chronic lack of sleep has been related to physical disorders such as diabetes and heart disease, as well as mental health difficulties, according to studies. Those looking to have a better understanding of what happens to them at night have two basic possibilities. They may either do a sleep test in a medical institution or use an app on their smartphone or smart watch, which is considerably more convenient but less precise. Many groups have begun creating novel sleep monitoring devices employing triboelectric nanogenerators, recognizing the necessity (TENGs). Eye masks, belts, patches, and even bed sheets have been used to power these self-powered devices. Ding Li, Zhong Lin Wang, and their colleagues aimed to modify this method to make it less restrictive and more pleasant, focusing on head movement during sleep.

The researchers created a flexible, porous polymer triboelectric layer to make this novel smart cushion. The electric field around neighboring electrodes is changed by movement between the skull and this layer, creating a current. They connected many of these self-powered sensors to form a flexible and breathable TENG (FB-TENG) array that can be put on top of a regular cushion. This technology was able to create voltage in proportion to the amount of applied pressure, as well as follow the movement of a finger drawing letters. 

The FB-TENG was also able to record the pressure distribution of a moving imitation human head. According to the researchers, this smart pillow might be used for more than just tracking sleep. The device might, for example, track people with disorders that impair head movement, such as cervical spondylosis, a degenerative neck ailment. Furthermore, they claim that the smart pillow might be modified to provide an early warning system for people who are at danger of slipping out of bed.