Wireless sensors are not difficult to understand; students majoring in electronics-related fields are quite familiar with them. To help you better understand wireless sensors, this article will introduce wireless sensor networks and the advantages of wireless sensors. If you are interested in wireless sensors, please continue reading.
I. Wireless Sensor Networks
1. Introduction to Sensor Networks
Wireless networks can be divided into two types. One type has infrastructure, requiring fixed base stations. For example, cellular networks like mobile phone communication require tall antennas and high-power base stations. The other type is infrastructure-free networks, including mobile ad hoc networks and wireless sensor networks (WSNs). These networks have distributed nodes without fixed base stations. Note that they still have base stations, just not dedicated fixed ones. Ad hoc networks refer to wireless self-organizing networks, and terminals in mobile ad hoc networks move quickly. Nodes in wireless sensor networks, on the other hand, are stationary or move very slowly. The official definition of a wireless sensor network is that it is a wireless network composed of a large number of stationary or moving sensors in a self-organizing and multi-hop manner. From this, we can see that sensor networks are mainly responsible for three functions: data acquisition, processing, and transmission, corresponding to sensor technology, computer processing technology, and wireless communication technology, respectively. Since sensor network nodes generally communicate wirelessly, the term "sensor network" refers to wireless sensor networks.
In a sensor network, some or all nodes can move slowly, and the topology dynamically changes as nodes move. Nodes communicate using an ad hoc method, with each node acting as a router and possessing the ability to dynamically search, locate, and restore connections. From the user's perspective, the wireless sensor network system architecture consists of sensor nodes, a sink node (similar to a gateway), and a management node. Functionally, each sensor node has dual functions of information acquisition and routing. It not only collects and processes local information but also stores, manages, and integrates data forwarded from other nodes, while collaborating with other nodes to complete various functions. The diagram below illustrates a sensor network system principle. A large number of sensor nodes are distributed across the monitoring area, forming a network through self-organization. After initial processing, the sensor nodes transmit the detected information to the sink node via multi-hop relay, and then the information is transmitted to the management node (the end user) via satellite, the internet, or other means. End users can also manage and configure the sensor network through the management node, such as issuing monitoring tasks.
A sensor node consists of a processor, an RF section, and a detection section. The processor handles computation and control functions, the RF section handles wireless communication transmission, and the detection section handles data acquisition. A convergence node, on the other hand, does not require a detection section; it only needs a processor and an RF module. However, convergence nodes typically have a more powerful processor module, including enhanced computing, storage, and communication capabilities. It can be an enhanced sensor node with sufficient power supply and more memory and computing power, or it can be a gateway device with a wireless communication interface (responsible only for data conversion). It facilitates data exchange between the sensor network and external networks.
II. Advantages of Wireless Sensors
For sensor systems, wireless configuration is a significant advantage.
First, the wireless configuration eliminates the risk of wire damage. Wires are susceptible to damage in harsh operating environments where vibration, wire fatigue, or high temperatures may occur. For rotating axis measurements, the wireless system eliminates the need for slip rings. Additionally, wires crossing hinge joints and link ends are also prone to damage.
While wireless sensing systems may be more expensive, they are faster to install and have a lower overall installation cost (especially in remote areas). Wireless systems also offer easier data acquisition, facilitating on-site diagnostics and the implementation of after-sales solutions.
From early challenges to today's practical applications
In the early days of wireless sensors, data loss and gaps could occur due to distance and intermittent issues. Through continuous development, this technology now employs improved radio communication and proprietary protocols to overcome these previous problems.
In the early stages of this technology's development, battery life was very short. This problem has been solved by introducing improved lithium-ion batteries and advanced power management solutions.
Today, wireless sensing technology has reached the level of standard applications in the industrial field. Wireless sensing systems have many advantages and their applications have become very widespread, including original equipment manufacturers (OEMs) and test and measurement applications; oil and gas; industrial machinery and manufacturing; off-highway vehicles; and aerospace and defense.
However, like all new technologies, wireless sensor technology initially lacked readily available standards, leading to a degree of uncertainty. Currently, several associations and organizations are working to develop standards for wireless sensors in various environments. Furthermore, in the early stages of using wireless sensors, their prices were prohibitive. Now, as wireless sensors are integrated into overall systems, their cost-effectiveness has significantly improved.
