Designing Wi-Fi connectivity into your embedded "Internet thing"

Embedded systems for a large variety of applications--including appliances, automation systems, medical devices, entertainment systems, and energy management--today already use or can potentially use a wireless interface.

And just like using an available wired connectivity mechanism, they also can choose from a number of available wireless systems. Zigbee, Bluetooth and proprietary wireless mechanisms have been used in numerous deployments, but there is a growing trend toward standard IP-based 802.11

Wireless LAN, or Wi-Fi as it is also known, as the primary wireless interface in embedded systems. This has not happened as a natural evolution--rather there has been a concerted effort from manufacturers of Wi-Fi devices, and from the Wi-Fi Alliance, in enabling ease of integration of Wi-Fi in embedded environments.

In this article we look at what defines ease of integration of Wi-Fi and how embedded-system designers can easily build systems with Wi-Fi connectivity. We examine hardware and software integration as well as the optimization of Wi-Fi parameters for robust and energy-efficient connectivity for these applications.

Building special purpose Internet "things"

Embedded devices are built for a specific purpose and are, by definition, based on a microcontroller as the core functional block interfaced to multiple peripheral modules providing specialized functionality with limited memory resources. These devices often need to communicate with external monitoring or control systems, and when this communication is based on the universal TCP/IP mechanism, they form a part of the rapidly growing ‘Internet of Things.’

Whatever the application of an embedded device may be, the development of the device can be complex. Hardware functionality, software procedures and system-level considerations would all have to be optimally handled. Microcontroller vendors, therefore, spend much effort in creating development or evaluation kits that greatly ease the software and hardware integration efforts.

The possibility of having Wi-Fi connectivity in an embedded system enables a plethora of new applications the system can address. However, since Wi-Fi was created to provide high speed data connectivity for networking market to start with, integration such technology into embedded devices poses many challenges.

Wi-Fi integration into embedded devices is a fairly recent trend; designers have to face a number of new considerations that involve hardware and software, as well as system-level aspects such as regulatory certification.

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A19 LED bulbs: What’s under the frosting?

Standard A19 format light bulbs, found today in most lamps and luminaires, are now available in LED versions that retail between $20 and $40 per 40-W- or 60-W-equivalent bulb. Some bulbs are dimmable, some not, and some only with specific dimmers. They all advertise 25,000 to 50,000 hours’ expected lifetime, based on three to four hours’ daily usage. If you use them appropriately and sparingly, you might expect your light bulbs to outlive you.

Each of the bulbs comes in a specially designed package, unlike tungsten filament and CFL bulbs, which ship in nondescript shrink wrap. The fancy packaging adds to the overall cost.



These bulbs clearly are not yet positioned as commodity items; they are expensive and are expected to last. But the price of electronic gadgets has dropped so much of late that longevity is no longer the main concern. So why is a common light bulb more expensive to buy than a cheap digital camera?

Looks count in a category as simple as light bulbs, and each of the bulbs we examined has a unique appearance. For example, the GE bulb has a ceramic neck and fins and a glass bulb, and is more costly than those using plastic and metal.

All of the bulbs have a small printed-circuit board contained within the neck, relying heavily on large electrolytic capacitors and transformers. The reliability factor of LEDs has increased tremendously.



All of the bulbs have a small pc board within the neck, relying heavily on large electrolytic capacitors and transformers.

Information is shared by www.irvs.info