**1. Introduction**

With the rapid development of information technology, the Internet of Everything turns more critical in the next technological revolution. Wearable devices, which have the advantages of good portability, easy to carry, and multifunctional capability, are considered as the basic hardware in the future, which show great potential on many applications, including medicine, healthcare, robotic systems, prosthetics, visual realities, professional sports, as well as entertainment. In recent years, much efforts have been devoted to developing wearable sensing technologies. Various kinds of wearable sensors have been proposed and demonstrated in lab, from single functional sensors, such as temperature [1], pressure [2], strain [3], optical [4], and electrochemical sensors [5], to multifunctional sensors, such as tactile and electronic skin [6]. Among these wearable sensors, wearable electromechanical sensors including strain and pressure sensor have attracted more and more attentions due to its clear mechanism, low cost, low power consumption, and high performance [7]. Through integrating wearable strain and pressure sensor with other sensors, tactile sensor [8] and electronic skin [9] have been realized. High-performance wearable electromechanical sensor can monitor the tiny change of strain and pressure, which is useful in many fields.

Traditional electromechanical sensor is usually fabricated with brittle materials, such as silicon and metal. Though flexibility can be improved by structural design, their performance is still limited. Thus, many new materials have been developed. The materials used in wearable electromechanical sensor consist of sensing and supporting material. Most of the progresses are focusing on the development of

new sensing materials. Structural design is also an effective strategy to improve the performance. Fabrication method is also the significant aspect. Many traditional techniques are utilized, such as screen printing, contact printing, electrospinning, and spray coating [10]. Moreover, wearable electromechanical sensor has been successfully demonstrated on a lot of applications, such as health monitoring, disease diagnosis, behavior correction, alarm of accident falls, human-machine interfaces, and even speech recognition.

The present chapter will discuss their basic working mechanism, fabrication methods, and applications of wearable electromechanical sensors and challenges facing the progress.
