Sensor Enables 'Smart Diapers,' Other Health Monitors

Penn State News

Adrienne Berard

February 2, 2023

Researchers at Pennsylvania State University (Penn State) and China's Hebei University of Technology have developed an electrode sensor that could be used to create wearable, self-powered health monitors. The low-cost hydration sensor can be drawn with a pencil on paper treated with sodium chloride; it exploits how paper reacts to humidity changes, using the pencil's graphite to interact with water molecules and the sodium-chloride solution. The paper can be connected to a computer to act as an environmental humidity detector. For wireless applications, the drawing is connected to a tiny lithium battery that powers data transmission to a smartphone via Bluetooth. The researchers used the technology to create a "smart diaper" that can detect wetness and signal for a change by integrating four sensors between the garment's absorbent layers.