Dongguk University researchers develop battery-free wearable sensor

Researchers at Dongguk University in South Korea have developed a self-powered, flexible neuromorphic device designed to mimic biological tactile sensing. The device, which utilizes a graphene-channel ion-gel-gated transistor (g-IGT) integrated with triboelectric nanogenerators (TENGs), can detect touch, vibration, or body movement and convert that mechanical energy into electrical pulses to power its own processing.

This architecture eliminates the need for an external battery, as the mechanical motion itself drives the artificial synaptic responses. The device demonstrates various levels of memory: sensory memory decays in approximately 70 milliseconds, short-term memory lasts between 0.2 and 0.45 seconds, and repeated stimulation can extend memory effects beyond two seconds.

Additionally, the system exhibits spike-rate-dependent plasticity (SRDP), meaning its response changes based on the frequency of incoming pulses. This learning-like behavior remains stable even when the flexible device is bent. In laboratory tests, the researchers successfully applied the system to a single-layer neural network for human-activity recognition, identifying various movements such as walking and sitting.