Ultrafast and Low-Power Graphene Wheatstone Bridge Respiratory Sensor

This letter presents a novel respiratory sensor that is both low-power and ultrafast and was manufactured using a standard graphene foundry service. The sensor is based on four microribbon patterned graphene resistors arranged in a Wheatstone bridge configuration, with two encapsulated resistors acting as a reference and the other two nonencapsulated resistors serving as sense resistors exposed to human breath samples. The sensor has demonstrated the ability to detect various patterns of human breath, with an average fall time of approximately 500 ms ± 23 ms and a rise time of around 560 ms ± 32 ms. Furthermore, the sensor also has been tested on six volunteers and has been used to measure breath variation during chewing a mouth freshener containing menthol, indicating its potential for respiratory sensing and breath analysis. The results indicate that the sensor can be utilized as a miniature wearable device that is lightweight and has low power consumption, with a power usage of only 0.3 mW.