Why is Power Factor so Important?

The specifications of any electrical appliance working on AC supply, such as a refrigerator, a toaster, a fan, etc., list a minimum of three important parameters – Voltage, Wattage and PF. The voltage rating indicates the nominal operating voltage of the appliance, the wattage rating indicates the power the appliance will use when switched on. The third parameter, PF, stands for the Power Factor – usually a value between 0.6 and 1.0. All electrical appliances consume power for operating or Read more [...]

What is stretchable electronics?

Imagine carrying your solar panel rolled up like a grapefruit while going camping and stretching it to the size of a room on the spot. It will not break, since it is made from fracture-proof electronics that is super compliant. Well, for the moment, that is the dream of Professor Darren Lipomi, department of Nano engineering, University of California at San Diego. Darren has a vision of self-repairing skins for sensors. A special super-thin layer of organic material will make up the stretchable Read more [...]

Raspberry Pi and Wolfram Alpha

If you are looking for something different from the regular Internet search that you get from Google, Yahoo or DuckDuckGo, try the new Computational Knowledge Engine Wolfram|Alpha (www.wolframalpha.com). In 2009, Stephen Wolfram Research released the new engine that could answer questions written in natural language. When you try out Wolfram|Alpha, you may be surprised that the site does not actually work like the search engines you are so accustomed to. In fact, you may not see results to some Read more [...]

Is banana pi tastier than raspberry pi?

It is surprising that for so long, no one had come up with a variant or clone of the ever-popular credit card sized single board computer, the Raspberry Pi or the RBPi. Ultimately, there is a Banana Pi from Lemaker, a China-based company. Banana Pi, although an RBPi-alike, is not a direct clone, but rather an evolution. Lemaker has used a more modern dual-core processor – the 1GHz ARMv7 AllWinner A20 - in place of the single-core ARMv6 700MHz Broadcom BCM2835. Lemaker has doubled the RAM to 1GB Read more [...]

How do you measure cable length?

Where miles of cable are involved, how do people determine where the fault lies and decide where to dig for initiating repairs? The method involves something very similar to how people determine the depth of a well, the distance of a cliff or the location of a thundercloud – by echolocation. If you know the speed of sound in air, you can find the distance of the sound source from the product of the amount of time sound is taking to travel the distance to its speed in air. For example, light travels Read more [...]

Will UEFI replace BIOS?

BIOS or the Basic Input Output System, designed by IBM for its Personal Computers has been with us for more than thirty years now. Whenever a computer is switched on, it conducts a self-check to see if it has a keyboard, a display and memories. Then it proceeds to look for a suitable Operating System. A small program, the BIOS, resident on a flash memory on the motherboard accomplishes all the above tasks. Once it has found a satisfactory operating system, it hands over the control of the computer. Read more [...]

How to Measure Large DC Currents Accurately

The market has several instruments for accurately measuring small DC currents, say up to 3A. You can also find some devices that can measure DC currents that extend beyond 50A with good accuracy. Large currents are common in photovoltaic renewable energy installations, grid energy storage, electric vehicles, to name a few. Usually, it is a common necessity for such systems to be able to predict accurately the state of charge or SOC of the associated energy storage batteries. Usually, systems for Read more [...]

Building a UPS with Raspberry Pi and Supercapacitors

It is always a dilemma when integrating a Raspberry Pi (RBPi) Single Board Computer into a project that works on the mains voltage and the RBPi has to turn it on or off. The difficulty is in deciding whether to power the RBPi separately or maybe power it from a UPS. Lutz Lisseck solved the problem in an ingenious way. He was looking for a way to shut down his RBPi gracefully, after it had turned off his ambient-lamp. Since the lamp operated directly from the mains and Lutz wanted to turn it on/off Read more [...]

Battle the Sun with a 21W LED and a Raspberry Pi

Lighting up an LED or an array of LEDs and controlling their brightness is a simple affair with the tiny credit card sized single board computer popularly known as the Raspberry Pi or the RBPi. The RBPi runs a full version of Linux and you can use it to drive an array of bright LEDs with it. If you construct it like Jeremy Blum did - he put up the LEDs on his graduation mortar board and wore the RBPi on his wrist on his graduation day - you can be sure of getting a lot of excited remarks from friends Read more [...]

What Is The Future Of The Internet?

Brazil and NET1 organized a major conference called NETmundial on April 23-24, 2014. Representatives of the tech community, civil society and governments convened to discuss the future of the Internet. Their focus was on how the Internet should be governed. The necessity for the event was multiple revelations, such as from Edward Snowden, about mass surveillance of digital communications by state agencies. As the President of Brazil stated at the 68th UN General Assembly, the absence of right Read more [...]