Interest in advancing the capabilities of flexible and wireless sensors is at an all-time high, owing to their widespread applications in healthcare, wearable electronics, robotics, and the internet of things (IoTs). However, the currently developed wireless wearable sensors require additional antennas to achieve wireless or real-time functions. The sensors operated with radio frequency signals (RF) can only provide limited positioning accuracy and are often ineffective in underwater conditions.
Northumbria University researchers have now developed a wearable sensor capable of wirelessly transmitting information via acoustic waves through air and water. With enough flexibility to be fitted into a wearable patch, researchers believe the flexible acoustic wave device could have multiple uses in healthcare and the water industry.
The research team was led by Professor Richard (YongQing) Fu, a professor in the Faculty of Engineering and Environment, University of Northumbria, and Professor Jin Xie at Zhejiang University in China.
In order to develop their device as a wearable patch, the team first identified surface materials that are flexible enough to withstand tiny vibrations capable of transmitting and receiving information. According to them, their design is multifunctional and could be used to wirelessly transmit information on a patient’s heart rate during hospital treatment.
During the lab tests, the sensors have also proven effective through the water. The distance measurement is achieved based on the phase differences of transmitted and received acoustic signals within a range of 100 cm, with a maximum error of 3 cm.
This study offers new insights into the communication and positioning applications using flexible acoustic wave devices, which are promising for wireless and wearable sensor networks. It could have practical applications, including diagnosing the location of a maintenance issue, such as a blockage, from within a metal water pipe.
“We feel it is a real breakthrough to have used a multifunctional and flexible sound wave device, operated based on electricity resulting from pressure and heat (piezoelectricity), for achieving integrated sensing, acoustic communication, and positioning functions,” Professor Fu explained.
“Based on this new methodology, this type of sensor could serve as an acoustic transmitter and receiver (transceiver) without any additional antenna, thus reducing the complications and size of the system,” Professor Xie added. “Because of the low velocity of the acoustic waves, the acoustic ranging and positioning can be directly performed, significantly improving precision when compared to those based on Bluetooth and Radio Frequency Identification (RFID).”