Author Archives: Andi

Is your anti-virus software really effective?

A popular concept floats around stating that anti-virus software simply does not work. Some sections of the press are known to propagate that the software products sold by anti-virus companies are rather ineffective in combating computer virus. Studies also influence these views on the efficacy of anti-virus software, such as the one conducted by a digital security agency in the USA. It infers that the high rate of virus growth on the internet outsmarts the bulk of anti-virus software commercially available. These software products fail to keep track of and provide adequate protection to computers against virus. Consequently, the effectiveness of these products is not commensurate with the cost of such software.

Some leading anti-virus providers have openly discarded these findings on grounds of ridiculously small sample sizes to be statistically correct, and declared the methodology used as inappropriate and unsound. They further consider the validation methodology – of simply examining the digital signatures – as poor and unscientific, not having run the study samples on live PC’s that such anti-virus software were actually supposed to protect.

The process of scanning signatures for malware detection is just one among several recognized methods of identifying the source of virus. Real anti-virus protection involves a lot more than that presumed in the aforementioned study. To be really useful, a complete suite of such methods must work in tandem, and that is the real safeguard against virus.

Consider a case of vehicle security, which could be a combination of an ignition lock, a door lock, gear lock, steering lock, immobilizer and a recent addition of GPS tracker, to name a few. Each of these provides a part of the protection using commercially available tools. The owner must decide the type and quantity of these he wants obtain and what he is willing to pay for them. A lopsided decision may defeat the very purpose of protection. It is like one installing a GPS tracker and an immobilizer in his car. A burglar may break the window glass and happily walk away with the expensive stereo, laptops and other valuables in the car, which the GPS tracker, or immobilizer may not be equipped to sense.

It is rather unjust to make a sweeping statement that anti-virus tools are no good in affording protection, without first deciding the level of security desired and having implemented solutions commensurate with such security. One needs to understand, with expert advice where necessary, the implications of using methods like firewalls, anti-phishing, anti-spam and so on, including what each can protect.

Another analogy to elucidate this concept is the performance of an orchestra, which does not depend solely on the violinist or the pianist, or even the entire range of musicians. Other important factors affect the performance, such as the conductor, the acoustics, the seats, the audience, and so on.

Irrespective of what popular opinion makes it out to be, if one is clear what one desires to protect and uses proper tools, it is very unlikely for one to conclude that anti-virus software serves no useful purpose.

Energy Harvesting – How & Why

What Is Energy Harvesting – Why Is It Needed?

The process of extracting small quantities of energy from one or more natural, inexhaustible sources, accumulation and storage for subsequent use at an affordable cost is called Energy Harvesting. Specially developed electronic devices that enable this task are termed Energy Harvesting Devices.

The world is facing acute energy crisis and global warming, stemming from rapid depletion of the traditional sources of energy such as oil, coal, fossil fuels, etc., which are on the verge of exhaustion. Not only is the global economy nose-diving, but the damage to the environment is also threatening our very existence. Natural calamities like earthquakes, tsunamis, droughts, floods, storms, etc., have become the order of the day. Economic growth is generating a spiraling demand for energy, goading us to tap alternative sources of energy on a war footing. Our very existence on the planet Earth is at stake, and we must find immediate solutions to meet the energy needs for survival.

Alternative Energy Sources Available

There are many, almost inexhaustible, sources of energy in nature. In addition, these energy forms are available almost free, if available close to the place where required. Sources include: Solar Energy, Wind Energy, Tidal Energy, Energy from the waves of the ocean, Bio Energy, Electromagnetic Energy, Chemical Energy, and so on.

Recent Advances in Technology

The sources listed above provide miniscule quantities of energy. The challenge before us is to gather the miniscule amounts and generate meaningful quantities of energy at affordable cost. Until very recently, this has remained an unfulfilled challenge.

Today, research and innovation has resulted in creation of more efficient devices to capture minute amounts of energy from these sources and convert them into electrical energy. Besides, better technology has led to lower power consumption, and hence higher power efficiency. These have been the major propelling factors for better, more efficient energy harvesting techniques, making it a viable solution. These solutions are considered to be more reliable and relatively maintenance free compared to traditional wall sockets, expensive batteries, etc.

Basic Building Blocks of an Energy Harvesting System

An Energy Harvesting System essentially consists of:

a) One or more sources of renewable energy (solar, wind, ocean or other type of energy)
b) An appropriate transducer to capture the energy and to convert it into electrical energy (such as solar cells for use in conjunction with solar power, a windmill for wind power, a turbine for hydro power, etc.)
c) An energy harvesting module to accumulate, store and control electrical power
d) A means of conveying the power to the user application (such as a transmission line)
e) The user application that consumes the power

With advancement in technology, various interface modules are commercially available at affordable prices. Combined with the enhanced awareness of the efficacy of Energy Harvesting, more and more applications and utilities are progressively using alternative sources of energy, which is a definite sign of progress to effectively deal with the global energy crisis.

Optional addition of power conditioning systems like voltage boosters, etc., can enhance the applications, but one must remember that such devices also consume power, which again brings down the efficiency and adds to cost.

Demystifying the A/D and D/A Converters

Analog and Digital Signals

Analog signals represent a physical parameter in the form of a continuous signal. In contrast, digital signals are discrete time signals formed by digital modulation. Most natural signals, like human voice and other sounds are analog in nature. Traditionally, communication systems were based on analog systems.

As demand for systems capable of carrying more information over longer distances kept soaring, the drawbacks of analog communication systems became increasingly evident. Efforts to improve the performance and throughput of systems saw the evolution of digital systems, which far surpasses the performance of analog systems, and offer features that were considered impossible earlier. Some major advantages of digital systems over analog are:

• Optical fibers can transmit digital signals and have virtually infinite information bearing capacity
• Combining multiple input signals over same channel is possible by multiplexing
• Digital signals can be encrypted and hence are more secure
• Better noise immunity leads to superior performance due to regeneration
• Much higher flexibility and ease of configuration

On the other hand, disadvantages include:

• Higher bandwidth required to transmit the same information
• Accurate synchronization required between transmitter and receiver for error free communication

Primary signals like human voice, natural sounds and pictures, etc., are all inherently analog. However, most signal processing and transmission systems are progressively becoming digital. Therefore, there is an obvious need for conversion of analog signals to digital. This facilitates processing and transmission, and reverse transition from digital to analog, since the digital signals will not be intelligible to human receivers or gadgets like a pen recorder. This need led to the evolution of Analog to Digital (A/D) Converters for encoding at the transmitting end and Digital to Analog (D/A) Converters at the receiving end for decoding.

Principle of Working of A/D and D/A Converters

An A/D converter senses the analog input signal at regular intervals and generates a corresponding binary bit stream as a combination of 0’s and 1’s. This data stream is then processed by the digital system until it is ready to be regenerated at the receiver’s location. The sampling rate has to be at least twice the highest frequency of the input signal so that the received signal is a near perfect replica of the input.

In contrast, a D/A Converter receives the bit stream and regenerates the signal by plotting the sampled values to obtain the input signal at the receiving end. The simplest way to achieve this is by using a variable resistor network, which converts each digital level into an equivalent binary weighted voltage (or current). However, if the recipient is a computer or other device capable of handling a digital signal directly, processing by D/A Converters is not necessary.

Two of the most important parameters of A/D and D/A Converters are Accuracy and Resolution. Accuracy reflects how closely the actual output signal resembles the theoretical output voltage. Resolution is the smallest increment in the input signal the system can sense and respond to. Higher resolution requires more bits and is more complicated and expensive, apart from being slower.

Measuring Temperature Remotely

How to Measure Temperature Remotely

In hostile atmospheres like toxic zones, very high temperature areas or remote locations, where objects are not amenable to direct temperature measurements, remote measurement techniques are deployed. In such applications, remote temperature measuring techniques are resorted to, and devices used include Infrared or Laser Thermometers as described below.

Infrared Thermometers or Laser Thermometers

These devices sense the thermal radiation, also called Blackbody Radiation, emitted by all bodies, and the emission depends on the physical temperature of the object whose temperature is to be sensed. Laser Thermometers, Non-contact Thermometers or Temperature Guns are names of variants that use lasers to direct the thermometer towards the object.

In these devices, a lens helps the thermal energy converge onto a detector, which in turn, generates an electrical signal, and drives a display after temperature compensation. The devices produce fairly accurate results and have a fast response, unlike direct temperature sensing, which is difficult, slow to respond to or not accurate enough. Induction heating, firefighting applications, cloud detection, monitoring of ovens or heaters are some typical examples of remote measurement of temperature. Other examples from the industry include hot chambers for equipment calibration and control, monitoring of manufacturing processes, and so on.

These devices are commercially available in a wide range of configurations, such as those designed for use in fixed locations, portable or handheld applications. The specifications, among others, mention the range of temperatures that the specific design is intended for, together with the level of accuracy (say, measurement uncertainty of ± 2°C).

For such devices, the most important specification is the DISTANCE-TO-SPOT RATIO (D:S) where D is the object’s distance from the device, and S denotes the diameter of the area whose temperature is to be measured. This implies that a measurement by the device concerned provides the average temperature over an area having a diameter S with the object placed at a distance D away from the device.

Some thermometers are available with a settable emissivity to adapt to the type of surface whose temperature is being measured. These sensors can thus be used for measuring the temperature of shiny as well as dull surfaces. Even thermometers without settable emissivity can be used for shiny objects by fixing a dull tape on the surface, but the error would be larger.

Commercially Available Types of Thermometers:

• Spot Infrared Thermometer or Infrared Pyrometer, for measurement of temperature at a spot on the object’s body

• Infrared Scanning Systems, for scanning large areas. This functionality is often realized by using a spot thermometer that aims at a rotating mirror, such as piles of material along a conveyor belt, cloth or paper sheets, etc. However, this cannot be termed a thermometer in the true sense.

• Infrared Thermal Imaging Cameras or Infrared Cameras are the ones that generate a thermogram, or an image in two dimensions, by plotting the temperature at many points along a larger surface. The temperatures sensed at various points are converted to pixels, and an image is created. As opposed to the types described above, these are primarily dependent on processor- and software-for functioning. These devices find use in perimeter monitoring by military or security personnel, and monitoring for safety and efficiency.

Solar Energy – a beginner’s look

Solar energy is an exciting field for both scientific study and home and office use, representing the modern drive to find clean, sustainable ways to power everyday life while protecting the planet for generations to come. Solar energy is created by the sun, which plays host to constant explosions of heat and energy. This energy radiates light that eventually reaches Earth, where water, land, and the clouds in the atmosphere absorb a portion.

This light manifests as heat and helps to regulate the planet’s water cycles, including rainfall. Solar energy is converted into food for trees and plants via photosynthesis, and in turn provides the Earth with oxygen and the natural materials necessary for human habitation.

With the many intrinsic and ancient benefits of solar energy we’ve enjoyed over the centuries, it is perhaps unsurprising that modern man has taken it upon himself to truly harness the potential of this natural power source. Solar power is fast becoming a popular way for businesses and homeowners to cut down on energy costs while making a commitment to the health of the environment.

Solar power itself can take many forms, operating for instance through the means of solar panels, which convert radiation from the sun to practical electric energy suitable for a variety of uses, and can store this energy in batteries.

Other common applications for solar power include pumps, switches, and fans for various industrial purposes, greenhouse and other thermal agricultural uses, and special technologies employed in space, such as those used to operate satellites.

Taking advantage of natural solar energy is not only an efficient way to power machines, houses, and more, but is cost-effective as well. Many entrepreneurs and environmentally savvy homeowners find that using solar power greatly diminishes their average monthly electricity expenditures, adding a welcome benefit to the clean and green energy source.

As oil prices fluctuate, and we become more aware of our impact on the global ecosystem, it is becoming imperative that we search for and use renewable sources of energy, and seek to live in a sustainable fashion, so that future generations can enjoy a happy and healthy planet. The use of solar energy through solar power panels and other technologies is an important step in reducing your overall energy footprint, and can give you — and your wallet — a sincere sense of peace and well being.

How to Make Your Own LEDS? Whooooooooa

I found this how-to today on the great Popular Science web site.

Now that I’ve read through the article – I am amazed that I’ve never seen these instructions written up before.

Theodore Gray, who authors their popular “Gray Matter” column, gives the full scoop on the basic materials used to construct LEDS and provides the basic instructions needed to see just how LEDS work.

OK, it is not so easy to find some synthetic silicon carbide (carborundum) laying around, but surely everyone could get their hands on some sandpaper, needles, a 9V battery and a snap. Follow his instructions, and VOILA…you’ve recreated the basic principles behind the creation of LEDS.

West Florida Components is Social!

Are you doing the whole Facebook thing? How about Twitter?

Well, we are….and we’re also on StumbleUpon, Digg, Delicious and a whole bunch more.

Why should you care? Because we give away a lot of discounts to our Facebook Fans and Twitter Followers! And our Facebook Fans and Twitter Followers are the first to know about newly discounted electronic components, parts and supplies.

We never overload our customers with too much communication but we like to keep in touch. The social media sites have given us a wonderful platform to connect with our customers.

Facebook

Facebook

So the next time your on Facebook, don’t forget to add our Fan Page to your list….we’re the same name over there as we are here: WestFloridaComponents (no spaces):
West Florida Components on Facebook

And here’s our Twitter user ID: westfloridacomp (had to be shortened because of their site):
West Florida Components on Twitter

So next time you feel like socializing, come on over and introduce yourself! We’d be thrilled to meet you.

Deal Alert! 50W Solar Panels Prices Slashed!

Don’t you wish you could save some money heating your house? Here’s a super deal you won’t want to pass up.

If you’ve been waiting to start building a solar energy system, you’re in luck. We are offering our 50W Mono-Crystalline Solar Panels at a outrageously low price of $299.99. We only have 6 4 left, so don’t delay! We expect the 50W solar panels to sell out quickly at this price. We’re trying to get more, but we can not be sure we will be able to.

Multiple 50W Solar panels can be connected in series for more voltage, or in parallel for more current. Use these to in part to build complete on grid and off grid solar power generating systems. Excellent for use with deep cycle battery banks and solar charge controller regulator.

Added benefit: Our solar panels are made of Monocrystalline silicon. Mono-crystalline has been proven to be the best and most efficient raw material used in PV cells. Use Mono-Crystalline panels to capture the most energy from solar power.

Solar energy is a small investment that delivers big benefits. Once you are harnessing the power of the sun’s rays, you’ll wonder why you waited so long!

LED Basics: How to tell which lead is positive or negative

Here are more questions we get asked a lot:
What is the positive (or negative) lead on an LED? How do you determine the polarity of an LED?

If you are talking about through hole LEDS, in most cases it’s pretty easy to determine the polarity.

Through Hole LED

Through Hole LED

If the LED has two leads, one longer than the other,the longer lead is the postive (also known as the anode) lead.

If the LED has two leads with leads that are equal in length, you can look at the metal plate inside the LED. The smaller plate indicates the positive (anode) lead; the larger plate belongs to the negative (cathode) lead. Unfortunately, some jumbo LEDS have the plates reversed so this is not a fool-proof method.

If the LED has a flat area (on the plastic housing), the lead adjacent to the flat area is the negative (cathode) lead.

It’s a little bit harder to determine the polarity with Surface Mount LEDS. Some are marked with a (-) to indicate the negative lead, but often, they are not. The single best way to determine the polarity is through the use a multimeter.

Surface Mount LED

Surface Mount LED

Set the multimeter to the diode/continuity setting. Usually,the multimeter will supply enough current into the LED which will just barely light it up. The black (common) lead on the multimeter indicates the negative (cathode) lead, and the red indicates the positive or anode side.

Of course, if you can find the datasheet for your LED, the pinout, along with all the other specs will be readily available on the datasheet.

Custom Console Stereo

For those of you wanting to hear just how good a custom built vacuum tube amp or console stereo will sound, here’s a video from Steve at Custom Tube Art which shows the workmanship of his projects and the quality of the sound.

Steve had this to say about his latest project:

Here is a 1960’s style custom console stereo I built displaying the vacuum tube amplifier right next to the Garrard type A turntable. The 807 tube amplifier has a conservative output of 30 watts per channel and uses 6SN7 and 12AU7 pre amp tubes. The speakers are a pair of Jensen 15″ drivers and a pair of DeForest 3″ tweeters in each cabinet. The entire project took two months to build.

You can see more of Steve’s custom work on his Vacuum Tube Amp web site.