Illustration of hair cells from the organ of Corti in the cochlear of the inner ear. Image: SPL

Single-wire sensors

12 January 2024

A research team led by Dr Yang Zhengbao from the Hong Kong University of Science and Technology have developed a one-wire reconfigurable sensor matrix that is capable of conforming to three-dimensional curved surfaces and resistant to cross-talk and fractures. 

Sensor matrices are combinations of multiple sensors arranged to produce a unique response pattern. They are used in robotics, aviation, health care and industrial machinery. Conventional sensor matrix systems are difficult to reconfigure, feature complex wiring and lack robustness.

Inspired by the way that the human brain processes sounds of different frequency, Yang and his colleagues reduced the number of output wires to a single wire by superimposing the signals of all sensor units with unique frequency identities. To demonstrate the advantages of this approach the team built a pressure sensor matrix and a pressure-temperature multimodal sensor matrix. Yang also showed how the technology could be used in monitoring strain distribution in an airplane wing. The findings are published in Science Advances.

The technology works by assigning a unique frequency to each sensor unit and using the sensor unit signal to modulate the amplitude of the frequency signal. This is similar to the way that distinct frequencies are processed by hair cells in the human cochlea. 

Comparison of sensor array schemes, fabricated 10 × 10 nonstretchable pressure sensor array and multimodal pressure-temperature sensor array prototypes. Image: Yang et al, Science Advances

Amplitude-modulated signals of different frequencies are then superimposed onto a single conductor and a Fast Fourier Transform algorithm is used to decipher the individual signals. The method allows the decoding system to process information from all sensor units simultaneously.

The sensor units are connected through a shared redundant network to allow reconfiguration and facilitate quick repairs. This design feature is inspired by the multiple synaptic connections between hair cells in the human ear and neurons. This feature would be useful in rapidly changing environments such as responsive robotics or adaptable wearable devices.