ZigBee Networks

Zigbee networks are called personal area networks (PAN). Each network contains a 16-bit identifier called a PAN ID.

ZigBee defines three different device types – coordinator, router, and end device.

Coordinator – Responsible for selecting the channel and PAN ID. The coordinator starts a new PAN. Once it has started a PAN, the coordinator can allow routers and end devices to join the PAN. The coordinator can transmit and receive RF data transmissions, and it can assist in routing data through the mesh network. Coordinators are not intended to be battery-powered devices. Since the coordinator must be able to allow joins and/or route data, it should be mains powered.

Router – A router must join a ZigBee PAN before it can operate. After joining a PAN, the router can allow other routers and end devices to join the PAN. The router can also transmit and receive RF data transmissions, and it can route data packets through the network. Since routers can allow joins and participate in routing data, routers cannot sleep and should be mains powered.

End Device – An end device must join a ZigBee PAN, similar to a router. The end device, however, cannot allow other devices to join the PAN, nor can it assist in routing data through the network. An end device can transmit or receive RF data transmissions. End devices are intended to be battery powered devices. Since the end device may sleep, the router or coordinator that allows the end device to join must collect all data packets intended for the end device, and buffer them until the end device wakes and is able to receive them. The router or coordinator that allowed the end device to join and that manages RF data on behalf of the end device is known as the end device’s parent. The end device is considered a child of its parent.

Read more

API Operation in xbee

API operation is an alternative to transparent operation. The frame-based API extends the level to which a host application can interact with the networking capabilities of the module. When in API mode, all data entering and leaving the module is contained in frames that define operations or events within the module.

Transmit Data Frames (received through the DIN pin (pin 3)) include:

• RF Transmit Data Frame

• Command Frame (equivalent to AT commands)

Receive Data Frames (sent out the DOUT pin (pin 2)) include:

• RF-received data frame

• Command response

• Event notifications such as reset, associate, disassociate, etc.

The API provides alternative means of configuring modules and routing data at the host application layer. A host application can send data frames to the module that contain address and payload information instead of using command mode to modify addresses. The module will send data frames to the application containing status packets; as well as source, and payload information from received data packets.

The API operation option facilitates many operations such as the examples cited below:

->Transmitting data to multiple destinations without entering Command Mode

->Receive success/failure status of each transmitted RF packet

->Identify the source address of each received packet

RF modules that contain the following firmware versions will support API operation: 1.1xx (coordinator) and 1.3xx (router/end device).

Read more

XBee

The XBee/XBee-PRO ZNet 2.5 OEM (formerly known as Series 2 and Series 2 PRO) RF Modules were engineered to operate within the ZigBee protocol and support the unique needs of low-cost, low-power wireless sensor networks. The modules require minimal power and provide reliable delivery of data between remote devices. The modules operate within the ISM 2.4 GHz frequency band and are compatible with the following:

• XBee RS-232 Adapter

• XBee RS-232 PH (Power Harvester) Adapter

• XBee RS-485 Adapter

• XBee Analog I/O Adapter

• XBee Digital I/O Adapter

• XBee Sensor Adapter

• XBee USB Adapter

• XStick

• ConnectPort X Gateways

• XBee Wall Router.

Read more

RESISTORS

A resistor is a two-terminal electrical or electronic component that opposes as eletric current by producing a voltage drop between its terminals is accordance with ohm's law V=IR The electrical resistance is equal to the current through the resistor where the temperature remains the same. Resistors are used as part of electronic network and electronic circuit.




since the elecronics are moving under the influence of a constant force should be accelerated to higher and higher velocities their motion should contiued ecen after we switch off the electric field kepping the circuit complete as already told it does not happen the speed of the electrons does not increase continousely and the current stop as soon as the electric field is switched off.

thus the eletrons of a conductor during their motion face opposition to their free flow similar in many respect to meachanical friction is diffrent for diffrent material it also changes with the size of the conductor

CAUSE OF RESISTANCE:-

When a potential difference is applied across a conductor as electric field is set up across its two ends when it is free electrons gets accelerated during their motion. The motion opposed the opposition offered by the atoms as a result of which the electrons are showed down is termed as the resistance of the conductor. Thus resistance is the opposition to the flow of current through a conductor

LAWS OF RESISTANCE:-

• Varies directly as the length of the conductor
• It is inversely proportional to the area of cross section
• It depends upon the nature of material of the conductor

Read more

samsung corby

Hybrid Design and Easy UI

The hybrid Touch & QWERTY form factor offers optimal versatility and ease of use. You can text friends and family with total ease and convenience using ergonomically designed slide out QWERTY keypad. With finger-friendly Touch Wiz users can effortlessly navigate through their favorite features. Online widgets give you instant access to all your favorite online contents with just a quick touch of the icon.

Perfect Texting and Email:

You will appreciate the ease with which you can do email, SMS and MMS. With B3410’s threaded message box, users’ messages are more organized and fun to read, an especially useful tool for socially active young people. The QWERTY keypad makes typing messages especially convenient, a must for high-volume texters.

Comprehensive SNS and IM Support:

With connection support for SNS, IM and Bluetooth, you can keep up to date with family and friends with maximum convenience. Whether sharing photos, sending a quick note, or just chatting about the day’s events, B3410 lets you do it all with speed and ease.

Versatile Music Player

You will enjoy listening to your favorite songs on the go with built-in music player. You will be impressed with the ease with which you can record favorite songs from FM radio just by pressing the shortcut key.

Read more

New Electronic Technology Advances Fuel Cell Developments

Researchers at Virginia Polytechnic Institute and State University, working under a research grant managed by the National Energy Technology Laboratory, developed a highly efficient converter that can boost low DC (direct current) voltage produced by solid oxide fuel cell stacks to the higher voltage required for conversion to AC (alternating current) for household and commercial applications. The boost is significant because it provides another technological step in reducing the efficiency, size, and cost of fuel cells.
Virginia Tech, which is applying for a patent on the technology, developed its converter in the Department of Energy’s Solid State Energy Conversion Alliance (SECA) Program, created to hasten the development of solid oxide fuel cells so they could be affordably marketed for power generation.

The significance of Virginia Tech’s work is that it facilitates the downsizing of the fuel cell stack and boosts net power output, while at the same time reducing the size and cost of the electronic systems behind it—key technical objectives for maturing solid oxide fuel cell technology to commercial-market self-sustainable status," according to NETL Project Manager Don Collins.

Virginia Tech’s device, when combined with highly efficient switching and digital control techniques, converts 22 volts to 400 volts at 97 percent energy efficiency. The device is able to boost voltage and reduce 120-hertz ripple current to 2 percent without the costly, bulky capacitors or additional converters that are customarily used. The net effect is that fuel consumption, the size of fuel cell systems, and costs are reduced, thereby taking a significant step toward SECA’s goal of 40–60 percent overall fuel cell efficiency at a cost of $400 per kilowatt by 2010. SECA studies indicate that each 1 percent improvement in inverter efficiency can reduce fuel cell stack costs by $5–$10 per kilowatt
Once their costs are reduced to the $400 per kilowatt level and efficiency goals are attained, fuel cells can be used as power generation resources in a variety of ways, such as onsite power for houses and commercial properties, transportation, and modular application by utilities. In addition, the flexibility of solid oxide fuel cells to be combined with turbines as ultrahigh efficiency hybrids contributes significantly to the Administration’s FutureGen concept, a plan for the zero-emission, high-efficiency power plant of the future.

Read more

Do you want to make a big profit from china electronics

We are integrated high-tech enterprise specializing in the development, manufacturing and sales of Eletronic products in China. We have over ten years of experience in this industry. And our excellent service has been successfully established and highly recognized in the domestic market as well as abroad. The Huge brand of our products comply with Europe environmental friendly standard, EC and enjoys the users favor of Europe, USA and South-east Asia, etc, which annual output is about thousands and millions of pieces! Our commitment is to satisfy your requirement, please trust that we will be your reliable business partner for our good reputation, good quality and competitive price! If you are interested in our product, pls feel free to contact with us or visit our website.

china smart phone t4288 WIFI GPS cheap smart phone t4288 WIFI EDGE GPS Quad band. 1. 624MHz CPU, hardwired decode VIDEO,support to play 640 * 480 very fluently 2. WIFI-support, EDGE, interesting and easy operation menu 3. Quad-band for you to use all around the world 4. 3 months to change a new color one, 15 months super-long warranty

ZOHOH W52 dual sim Bluetooth java TV WIFI 2.4 inch screen At first glance ZOHOHw52, seemingly without striking appearance is indeed difficult to impress us. However, is this somewhat undistinguished-looking phone, but with that you can not imagine too powerful features. The ZOHOw52 body like you can experience the wifi bring your surfing pleasure. Built-in Java2.0 and gravity sensing acceleration, support for analog TV, and opera Mini Theater, ZOHOw52 full range of entertainment functions. 2 million pixels, dual cameras, comes with lens protector as well as flash and other devices, which greatly satisfy the needs of photography enthusiasts.

Languages allow the choice of friends in 20 countries have the opportunity to experience full-featured ultra-powerful mobile

Sciphone i68 Apple's series mobile phones starting from CECT599 a single card developed to P169-9 dual-card single. In June launched the first Sciphonei68 is Apple's series mobile phones, into the dual sim dual standby dual Bluetooth ranks.

Read more