TEKNIK ELEKTRONIKA

cabled’ in consumer electronic and the PC scene in particular. Just when we all thought radio was a thing of the past, it came back with a vengeance and is now carrying data instead of just audio or TV signals.

 

Wireless is inevitably tied to RF design technology, a nightmare for many electronics designers who like to stick to DC, programming and the odd signal reaching up to a megahertz or so. Fortunately much of the black magic associated with RF in connection with data transmission can be left to specialized designers who over the past years have come up with small, cheap and off the shelf modules, making the RF link transparent.

 

The choice of modules currently depends on the transmission distance: a few centimeters using Near Field Communication (NFC) or Radio Frequency Identification (RFID), tens of metres with the Bluetooth, Wi-Fi or ZigBee systems, or indeed thousands of kilometres using a module for receiving GPS data.

 

In accordance with the principle of the Elektor Toolbox series, we’ve brought together technical documentation (spec. sheets, application notes, user guides, etc.) on various devices according to the frequency and/or protocol used. All of the documents are PDF files. Browsing around the DVD is made easy by an HTML menu. Finally, this Wireless Toolbox DVD contains a collection of articles on this topic (RFID, xBee, DCF77, GPS, infrared, etc.) that have appeared in Elektor magazine.

 

This DVD packs 1.2 gigabytes worth of technical documents!

 

Contents: Antennas

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With more and more phone users switching to DSL or cable networks and using mobile phones instead of landline phones, there is a growing scarcity of fixed telephone lines that are compatible with conventional analogue modems. To  remedy this situation, eDevice has developed the WireX machine-to-machine wireless communication converter, which it claims is the first mass-market communication converter for machine-to-machine links. According to eDevice, installation is easy and users with a data volume of 1 MB per month can reduce their communication costs by more than 50% by switching from a dedicated phone line to WireX.

 

The WireX converter allows legacy equipment with embedded analogue modems to be communicate using a mobile telephone network (GSM or GPRS) instead of the conventional telephone system. It is designed for to be installed directly by the end user and does not require any changes to the existing legacy device; the user only needs to disconnect the phone cable from the wall and plug it into the WireX adapter. The data previously transferred over the phone link is then automatically transmitted over a GSM or GPRS network using phone line emulation.

 

In the home environment, WireX can be used with various types of existing devices equipped with analogue modems, including remote patient monitors, telecardiology monitors, alarm and security systems, and TV set-top boxes. In a SOHO or small business environment, it can be used to convert point-of-sale equipment, energy metering systems, and security and access control devices to wireless communication.

 

Image: eDevice

  

 

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Cambridge Consultants Ltd. has launched software to provide wireless connectivity between a medical device and online health services conforming to the Continua Health Alliance standard. The product combines a wearable mobile phone from Qualcomm Inc. with Cambridge Consultants’ Vena software stack. This arrangement enables data collection from Continua-certified devices over the Continua Personal Area Network (PAN) interface and data transmission over the Continua Wide Area Network (WAN) interface to online health services.

Qualcomm Wearable Mobile Device 1X, 1X EV-DO and UMTS modules support a variety of 3G networks and provide integrated GPS capability, an accelerometer and Bluetooth technology. With data and voice support, a standard USB 2.0 interface, defined APIs and a development kit, the modules are claimed to provide unprecedented functionality and streamlined 3G connectivity for M2M and CE devices.

The Vena wireless healthcare software stack embeds the Bluetooth Health Device Profile (HDP) and IEEE 11073 standards for the exchange of information between health devices. According to Nick Vassilakis, a business development consultant at Cambridge Consultants, the Vena software stack is designed to use emerging industry standards and enable the rapid development of compact, low-cost wireless health care devices.

The Continua Health Alliance is a non-profit, open industry coalition of healthcare and technology companies with more than 200 member companies. The Continua Design Guidelines specify how to use existing standards to build interoperable personal health care solutions. The group's version 1.5 design guidelines add the definition of the WAN interface and include two additional wireless technology standards for low-power radios.

Image: Cambridge Consultants

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The Tinytag wireless data logging system distributed by Priggen Special Electronic (PSE) consists of a receiver connected to a PC and a number of wireless logger modules, called Tinytag radio loggers. Each wireless logger is a self-contained, battery powered unit that can receive, log, store and transmit data to other logger modules, as well as the central receiver.

The maximum line-of-sight range of each logger is 200 metres, but thanks to the data relay function of the loggers, there is effectively no limit to the number of loggers in the system or how far away they are. Data will always find its way back to the PC because it can be relayed from one logger to another logger in range until it finds its way to the receiver. The self-configuring loggers dynamically adjust to obstructions. If a logger is unable to find a path back to the receiver, its data is stored up to 2 weeks locally until a path becomes available.

This combination of features delivers a very robust wireless network which ensures that data is never lost during transmission. The radio software has mechanisms for third party software integration using Modbus or HTTP accessible CSV files. The software is also fully compatible with wired Tinytag products. Data from the receiver can be accessed over a network, and alarm messages can be forwarded via e-mail or text messaging.

The loggers are housed in rugged waterproof (IP67) enclosures for operation in harsh industrial environments and outdoors. They are available in versions for connecting one, two or four external temperature sensors, or with a built-in temperature and humidity sensor. A variety of thermistor probes and a compost probe are available as accessories.

Operation of the wireless system is licence-free in the European Union at 869.8 MHz. Versions for Australia and America are also available. The user replaceable alkaline batteries have an operating life of up to one year, and low battery level is indicated.

Typical applications for the wireless data logger system are monitoring chiller chains, warehouses and buildings, capturing environmental data, and monitoring composting processes.

Image: PSE


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wireless IC solution designed to reduce the cost and complexity of one-way wireless links used in a wide range of consumer, industrial and automotive systems. The new Si4010 system-on-chip (SoC) RF transmitter enables developers to optimize remote keyless entry (RKE), garage door opener, remote control, building automation and security device designs for the lowest system cost and highest performance while ensuring one-way link integrity.

The Si4010 RF transmitter is the industry's first single-chip remote control IC requiring only one external bypass capacitor, a printed circuit board, battery and external case with pushbuttons to create a complete wireless remote control. Based on a patented crystal-less architecture, the Si4010 achieves

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Bandwidth demand and tall buildings make running a wireless network in certain cities challenging.Cities such as New York and San Francisco can strain wireless networks
They have a large concentration of iPhone owners who love to complain in the press
PC World: Test shows AT&T's network almost always faster than competitors
Spokesman: AT&T adding more bandwidth to support faster speedsEditor's note: Business Insider is contributing a series of columns to CNN.com that challenge commonly held beliefs about the tech world.
(Business Insider) -- Here's the truth about AT&T's wireless network: On the whole, despite what you've heard, it's not actually that bad. It's just bad for the wrong people in the wrong places -- mostly tech- and media-types in New York and San Francisco, California.
Those two cities in particular -- and parts of other big cities, like downtown Chicago, Illinois -- are sort of the perfect storm for AT&T.
There's a huge concentration of Apple iPhones, owned by tech- and media-savvy folks who demand a ton of bandwidth, and love to complain loudly on Twitter and in the press. And there are tall buildings, landlords and construction processes that make running a wireless network more challenging.
That helps explain why there are so many dropped calls and pokey mobile Internet connections in those cities, and also why there are so many angry tweets and news articles.
And that's why even Apple CEO Steve Jobs has come to AT&T's side, defending how his partner has tried to beef up its infrastructure in its most troubled markets. At a recent press event, Jobs said that when AT&T wants to add a cell tower in Texas, it may only take three weeks. But in San Francisco, on average, it takes three years.
"No one wants a cell tower in their back yard, but everyone wants perfect reception," Jobs said, according to a rough transcript.
The rest of the country, overall, isn't such a mess for AT&T. How can we tell? One way is to look at AT&T's customer turnover statistics to see if people are fleeing from AT&T and its supposedly terrible service. The reality is that they are not.
During AT&T's second quarter, its monthly "churn" -- the percent of customers who leave every month -- was 1.29 percent. If you exclude prepaid subscribers, who tend to switch carriers or discontinue their service more often than average, AT&T's monthly churn was even lower, at 1.01 percent. Those are both record lows for the company and represent improvement over the same period last year.
How do those stats compare to the rest of the wireless industry? You'd think that Verizon Wireless -- whose network has a stellar reputation compared to AT&T's -- would have much, much lower churn. Not quite.
Verizon Wireless customers are indeed more loyal than AT&T's, but barely. Its monthly churn last quarter was 1.27 percent, only a hair below AT&T's. If you exclude prepaid subscribers, it was 0.94 percent -- again, better than AT&T's, but not by much. For comparison, Sprint was almost twice as bad, and T-Mobile was more than twice as bad as AT&T and Verizon.
If things were that bad at AT&T -- and comparatively, that much better at Verizon Wireless -- you'd expect a greater difference in their churn rates.
Another recent study leans in AT&T's favor. A 3G wireless performance test carried out by PC World showed that AT&T's network was almost always faster than its competitors, and that its reliability was on par. Both measurements showed significant improvements over its 2009 tests. But indeed, AT&T's performance and reliability in New York and San Francisco weren't as strong as in other cities, such as Seattle, Washington, or Baltimore, Maryland.
Anecdotally, I've noticed similar things traveling around the country with an iPhone and 3G-enabled iPad. Last weekend in Maine, my 3G connection seemed much snappier than it typically does in New York. I was even able to stream a Netflix video to my iPad in a moving bus -- something I can't even do reliably when I'm stationary in Manhattan.
AT&T pours billions of dollars -- between $18 billion and $19 billion this year alone -- into trying to improve its network. For example, it's going cell site by cell site to add more bandwidth to support faster speeds, a process that will continue through this year and next, an AT&T spokesman says.
Many of the carrier's improvements have focused on New York and San Francisco. For instance, AT&T has doubled the capacity of its network in New York over the past year, and is in the process of doubling its capacity in San Francisco. It has also installed specialized indoor systems in high-traffic areas, including Grand Central Station and Yankee Stadium in New York.
As a result, mobile download speeds in New York are up 31 percent over the last six months, according to internal testing data. Blocked calls are down almost 40 percent in Manhattan so far this year, and dropped calls are down 23 percent, AT&T says.
The company has also complemented its strained 3G network with more free wi-fi hot spots for its customers, including a network recently installed in New York's Times Square, one near Wrigley Field in Chicago and all Starbucks locations.
In addition to adding 400 percent more 3G capacity at AT&T Park in San Francisco, it has also doubled the number of wi-fi hot spots there. In those situations, the idea is that customers could hop on wi-fi to send emails or access the Internet, taking a load off cell networks.
To be sure, despite these improvements, the company obviously still has a lot of problems in New York and San Francisco. And because of the concentration of tech and media industry types there, we'll probably see the "AT&T sucks" rants and "attfail" tweets for the foreseeable future.
At least until Verizon Wireless gets Apple's iPhone. Then we'll know if this whole mess is really AT&T's fault or just the unique situation of having to support millions of iPhones in use at one time.
But in reality, things aren't as terrible for AT&T as you've been led to believe. It's just really bad in the wrong places, for the wrong people.
Copyright © 2010 Business Insider.
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