Wireless sensor networks testbeds and state-of-the-art multimedia sensor nodes

In recent years, Wireless Sensor Networks (WSNs) attracted researchers' attention. This has led to advancements made in both hardware design and software components. The research at the hardware level has resulted in a variant of WSN called Wireless Multimedia Sensor Networks (WMSNs). WSNs have application in battlefields, industrial process monitoring, and environmental monitoring, to name but a few. Furthermore,WMSNs have the potential for real-time object detection and recognition. It can be used to locate misplaced items, assisted living, helping people with cognitive impairments, species detection, and providing real-time images for many other surveillance-based applications. Thus, such networks need to operate in a diverse environment. Researchers invariably test their designed algorithms and protocols using simulation tools. Simulators do not accurately model the environment in which such networks are deployed. Therefore, there exists many WSNs and WMSNs testbeds. These testbeds enable researchers and programmers to validate the performance of their algorithms and protocols on a physical network. In this paper, we provide a detailed description of various state-of-the-artWSN testbeds.We have evaluated these state-of-the-art testbeds on a set of metrics. Furthermore, we survey the state-of-the-art in wireless multimedia sensor nodes hardware along with their eminent features.