Wireless sensor networks

Wireless integrated network Sensors (WIRELESS INTEGRATED networks System,wins) provide distributed networking and Internet access for embedded sensors, controllers, and processors. WINS began in 1993 by the University of California and the University of Los Angeles, and 3 years later launched the first generation of WINS devices and software. Subsequently, the high-power wireless integrated micro-sensor (low power Wireless Integrated Microsensor,lwim) funded by the Defense Advanced Research Program verified the flexibility of the multi-hop, self-organizing wireless communication network. At the same time, the first generation network verifies the flexibility of micro power level wireless sensor node and network operation algorithm. At present, the basic network structure and auxiliary electronic components of WINS are not very different from wireless sensor networks.

WINS technology is used earlier than wireless sensor networks and wireless mobile sensor systems. WINS was initially primarily used in areas such as transportation, production, medical, environmental monitoring, security systems, and urban traffic control to simplify monitoring and control. By combining sensor technology, signal processing technology, low power technology and wireless communication technology, WINS is mainly used for low-power, low-speed, short-range duplex communication. In some wins architecture-based systems, sensors require continuous detection of events. All components, sensors, data converters, caches, etc. all work in the micropower stage. After the event detection, the microcontroller publishes commands to the signal processor, and then the node work protocol determines whether to alert the remote user or the neighboring wins node, and the WINS node provides the properties of the acknowledgement event. Because WINS is locally connected through a short-distance, low-rate communication device to many sensor nodes, the detached node is adopted in the network structure for multi-hop communication. In dense areas of wins, this multi-hop structure allows for link communication between nodes, thereby enhancing narrowband communication capabilities and reducing power dissipation when dense node layouts are used.

Currently, most sensor nodes are battery-powered, and the main factor restricting wins nodes is cost and power requirements. In this way, the use of low-power sensor interface, CMOS micro-power components and signal processing circuit can prolong the working time of the WINS node. The traditional WINS RF system design is based on the combination of an integrated chip and a board-level element that can drive a Q-resistor load, but a set of active and passive components will result in an increased impedance value and lower power consumption. For this reason, the impedance of each constituent system within or between the system is controlled by a high Q-value sensor introduced by each node, so that the narrow band, high output impedance of the metal oxide semiconductor circuit can be converted from the low frequency band to the corresponding band width of the high frequency band. Furthermore, in order to improve the detection range of wins in the case of strong background noise, the sensor sensitivity must be optimized.

In recent years, the embedded wireless Communication and network protocol of WINS is one of the research hotspots. Embedded wireless communication networks typically operate in Xu Ke-free 902~928 MHz bands at 2.4 GHz, including spread spectrum communication, signal encoding, and multiple access. The WINS system works under the condition of low power, low sampling frequency and limited background environment, and the WINS network supports multi-hop communication through wireless bridge and traditional wired communication network equipment. Compact geometries and lower costs make wireless integrated sensors less expensive to configure and distribute, accounting for only a small fraction of traditional wired sensor systems. At present, WINS has formed self-organization, multi-hop frequency division multiple access (Frequency Division multiple ACCESS,FDMA) and time division multiple address (Time division multiple) network protocol model. The technology of realizing micro-power wins system on a chip can build a new, embedded sensor and computing platform. Furthermore, smart wireless sensors and digital signal processing technologies will further advance wins's larger-scale applications.

The TELOSB full name is Rev. Crossbow (KOESBO) Company Telos series node. B. In a wireless sensor network, each entity element is called a sensor node. TELOSB is one of the nodes. As shown in the image on the right, the node size is about the U disk size, above the circuit board, below the battery slot. The specific parameters are as follows:TELOSB

Technical origins	University of California, Berkeley
Cpu	8MHz TI MSP430, 10KB RAM
Communication chip	CC2420
Communication Radio	2.4GHz Radio, 250Kbps high-speed data transfer
MAC protocol	IEEE 802.15.4/zigbee
External Flash	1M Flash
Antenna	Built-in, integrated inside the board
Operating system	TinyOS 1.1 or higher
Write program	Write via USB port
Power supply	Two AA batteries (No. 5th battery)
Temperature and humidity sensing components	Sensirion Sht11
Light sensing components	Hamamatsu S1087 (s1087-1)
Led	3, respectively 0 (Red), 1 (Green), 2 (Blue)

Wireless sensor networks