This design mainly applies Zigbee wireless technology in LED lighting engineering, which solves the problem of serious power consumption and short service life of incandescent lamps. At the same time, it solves the complicated wiring, high power consumption, waste of resources, distance limitation and maintenance in lighting engineering. Difficult problem. Based on Zigbee technology, it has the advantages of short distance, low power consumption, low data rate, low cost and low complexity. It designs a smart home LED lighting wireless control system based on Zigbee technology. Mainly using Zigbee wireless ad hoc network technology, it realizes the wireless control of LED lamp switching and brightness adjustment, and the function can be divided into single lighting control and local lighting control.
At present, China has vigorously promoted the policy of replacing incandescent lamps with LED lamps, and it will be implemented within five years. This policy solves the problem of serious lighting power consumption and short service life. In addition, the engineering wiring is complicated and complicated to install, and it is difficult to move control. The problems of high consumption, long construction period, and difficult maintenance in the later period still need to be solved. The wide application of Zigbee technology provides a solution to the current problems, and it is convenient and quick for family life and office buildings. Comprehensive management personnel achieve high efficiency and security purposes. In this paper, a design scheme combining Zigbee wireless ad hoc network technology and LED energy-saving lamps is proposed to realize the functions of continuous adjustment and remote control of the brightness of LED lamps. The software and hardware design system is introduced in detail.
1 Zigbee wireless technology
Zigbee technology is a wireless communication technology between various electronic devices used in short-range and low transmission data rates. It is developed based on the 802.15.4 wireless standard approved by IEEE. An application outline shared between different manufacturers. Zigbee-compatible products operate at 2.4 GHz, a worldwide free open frequency band that provides 16 transmission channels, each of which automatically selects the channel with the cleanest interference minimum for data transmission. In the network layer, the star and mesh topology can be adopted. According to the different functions of the node, it can be divided into the central coordinator Coordinator, the routing node Router and the terminal node FFD. Among the three topologies, it is not easy in the star network. To implement Zigbee's advanced features, routing, each Zigbee device can only communicate directly with PANC. The mesh network is the most complex, allowing routing, and the route of the route is the best path automatically calculated. After the network is established, any device fails, and the devices in the network recalculate the route of the route so that it does not affect the network. The device is communicating normally.
Therefore, the system adopts a tree network structure, which is simple and easy to implement.
1.1 Advantages and features of Zigbee
1) Low power consumption is the most advantageous place for Zigbee technology. In the communication state, the Zigbee terminal consumes several tens of milliwatts. In the power-saving mode, the power consumption is only a few tens of μW, and a dry battery can work for nearly one year.
2) Reliability: Avoid collision mechanism, and reserve dedicated time slots for communication services requiring fixed bandwidth to avoid conflicts when sending data; node modules have automatic dynamic networking functions, and the information transmitted is throughout Zigbee. The network transmits by means of automatic routing, thus ensuring the reliability of information transmission.
3) Large network capacity: On the same WPAN, there can be 65 536 ZigBee devices, which can transmit information through multiple hops, and have wireless network self-healing function.
4) The effective range is large: the effective range is between 10~75 m, if the preamplifier can reach the communication distance of 1 000 m.
5) Low cost: Zigbee data transmission rate is low, the protocol is simple and patent fees are free, so the cost is reduced.
1.2 Zigbee Wireless Networking Principle
In the network layer, ZigBee defines three roles: The first is the central coordinator, which is responsible for establishing the network and allocating the nodes of the network; the second is the router, which is mainly responsible for finding the network and establishing And the routing path of the repair data, and is responsible for forwarding the data, the router can communicate with the coordinator, or can communicate with the terminal node, and the communication can also be communicated between the routes; the third is the terminal node (FFD), which can only choose to join The formed network can send and receive data information with the router, but cannot forward information and does not have routing function. The communication diagram is shown in Figure 1.
Figure 1 Communication diagram
Working principle: Each terminal node or router in the system controls one light or multiple lights, each node has a separate network address, and the handheld control terminal sends a command to the coordinator through the wireless module, and the coordinator will receive the command. Send to each node by wireless transmission.
Lead Free Piezoelectric Elements
The Co-Al Co-doped Barium Titanate
Lead-free Piezoelectric Ceramics was successfully developed by Yuhai company
through repeated experiments. By Researching the influence of Co-Al Co-doping
on the structure and properties of Barium Titanate-based piezoelectric
ceramics, the formulation and preparation technology of Barium Titanate-based
piezoelectric ceramics were optimized. Yuhai`s BaTiO3 was prepared by conventional
solid-phase sintering method, with the piezoelectric constant d33 (>170pC/N),
dielectric loss tgδ≤0.5% and mechanical coupling coefficient Kp≥0.34.
Barium titanate lead-free piezoelectric
ceramics are important basic materials for the development of modern science
and technology, which was widely used in the manufacture of ultrasonic
transducers, underwater acoustic transducers, electroacoustic transducers,
ceramic filters, ceramic transformers, ceramic frequency discriminators, high
voltage generators, infrared detectors, surface acoustic wave devices,
electro-optic devices, ignition and detonation devices, and piezoelectric
gyroscope and so on.
Application: military, ocean, fishery, scientific research,
mine detection, daily life and other fields.
China Patent of Yuhai company`s BaTiO3
Chinese Patent No.: ZL 2011 1
0126758.6
Name: Lead-free Barium Titanate
Piezoelectric Material with Addition of Cobalt and Aluminum
Lead free piezo material BaTiO3
Lead-free Material
Properties
BaTiO3
Dielectric Constant
ɛTr3
1260
Coupling factor
KP
0.34
K31
0.196
K33
0.43
Kt
0.32
Piezoelectric coefficient
d31
10-12m/v
-60
d33
10-12m/v
160
g31
10-3vm/n
-5.4
g33
10-3vm/n
14.3
Frequency coefficients
Np
3180
N1
2280
N3
Nt
2675
Elastic compliance coefficient
Se11
10-12m2/n
8.4
Machanical quality factor
Qm
1200
Dielectric loss factor
Tg δ
%
0.5
Density
Ï
g/cm3
5.6
Curie Temperature
Tc
°C
115
Young's modulus
YE11
<109N/m3
119
Poison Ratio
0.33
Piezo Element,Piezo Ceramic Elements,Piezoelectric Ceramic,Pzt Tubes
Zibo Yuhai Electronic Ceramic Co., Ltd. , https://www.yhpiezo.com