Wireless wearable sensors are collections of independent devices with computational, sensing and wireless communication capabilities. Research in this area has been growing in the past few years given the wide range of applications that can benefit from such a technology. Wearable technology is ubiquitous to the user. Thus, it has the potential to be significantly disruptive to the user's daily life. Miniaturized and flexible wireless sensors are mostly easier to integrate into everyday objects and show very high mechanical robustness. Continuous miniaturization of electronic components has made it possible to create smaller and flexible electrical devices which can be worn and carried all the time. The potential miniaturization degree is derived according to different hardware technologies. The results are verified by prototype implementations. In this paper, the development of a flexible wireless platform with embedded passive components for wearable sensor described. The target of this paper is not only miniaturization but also moving toward flexible system which enables freedom in design and application. The system incorporates a main board, sensor board, energy source and extension sensors. Concept development, design, and non-electrical features are discussed in this paper.