Friday, February 19, 2016

Li-Fi: Connect to the Internet using an LED bulb

Imagine an LED bulb doubling up as an access point for connecting to the internet and ordinary light being used as a medium to carry data.

A whole new world wherein a bulb would not only give us light but also help us access the web might not be too far way, if a new technology called Li-Fi (or Light-Fidelity) goes mainstream.

Prof Harald Haas of the University of Edinburgh, who coined the term Li-Fi in 2011, demonstrated the new technology to a packed auditorium at the Wipro’s Electronics City campus on Wednesday. He streamed a video from the internet on a laptop using light from an LED bulb to access the web.

Prof Haas said Li-Fi is a disruptive technology that could transform business models, create new opportunities, and is poised to be a $113 billion industry by 2022.

He said that the RF (radio frequency) spectrum will not be enough considering the rate of growth of wireless data communication. The visible light spectrum is much larger. The use of the light spectrum for Li-Fi overcomes the issues in traditional wireless communication, like the shortage of spectrum and network disruption because of interference.

In Li-Fi, anyone who has access to light can access the internet. The system also allows users to move from one light source to another without losing their network connection. What about connecting to the internet in the night? The stream of photos can be reduced to a minimal level that won’t produce visible light but enough to carry data.

Prof Haas said though Li-Fi was poised to compete with Wi-Fi, it is not meant to replace it. “We are not looking at an either-or situation.”

Though the inability of light rays to pass through walls and similar structures is seen as a major drawback of this technology, Prof Haas has a totally different view. He said it’s an advantage since restriction by walls provides more security to the network and eliminates the risk of the signal leakage to eavesdropping.

The Li-Flame, described as the world's first true Li-Fi system, was displayed at the Mobile World Congress in Barcelona in March last year. The third generation of products have now been developed and will be on display at the MWC later this month.


Light-Fidelity is a new technology that uses light waves, instead of radio frequency waves, as a medium to carry data. An improvised LED bulb functions as a router


  • An ordinary off-the-shelf LED bulb connected to an device, which in turn is connected to the internet.
  • Internet data flows in via the device into the bulb, and is carried by light waves.
  • At the other end, light waves carrying internet data falls on a receiver or a dongle which is connected to the computer.

  • Visible light spectrum is available in plenty, unlicensed and free to use.
  • Double benefit of a bulb giving us light as well as internet access
  • Low interference leads to very high data speed
  • Li-Fi works under water as well
  • Not harmful, unlike RF that can interfere with electronic circuitry
  • Light won’t pass through walls, making eavesdropping nearly impossible
  • LED illumination is already efficient and data transmission needs very little additional power.
  • It can achieve about 1,000 times data density of Wi-Fi, since light can be contained in an area

  • July 2011: Prof Harald Haas coins Li-Fi at TEDGlobal
  • Jan 2012: PureLifi founded
  • Sept 2013: Launch of first product Li-1st
  • Dec 2014: Second product Li-Flame developed
  • Nov 2015: Prof Haas demonstrates Li-Fi using solar cells at TEDGlobal
  • Dec 2015: Latest product LiFi-X developed

Saturday, February 13, 2016

Book Review - 101 Amazing US Presidential Facts

101 Amazing Presidential Facts: Fun trivia about every American President from Washington to Obama! (American Presidents Series)
This is the Presidential election season in the United States, and that's one reason I picked up this small book of trivia. Good fun reading lots of interesting things about all the US Presidents, right from George Washington to Barack Obama. This can be a good resource for people who are interested in quizzing. It talks of:

  • The first President to actually live in the White House.
  • Presidents who have died on Independence Day.
  • The President who died within one month of being sworn in.
  • The first President to wear a blue jeans to the Oval Office
  • The President who got a speeding ticket because he drove the horse too fast
  • The first President to use a telephone in the White House
  • The first President to ride in an automobile. But more interesting is what was special about that journey
  • The President who is related to 11 other presidents by blood or by marriage
  • The first President to run a full marathon.
  • The President who gets hair cut every week

And so and so forth...

101 Amazing Presidential Facts: Fun trivia about every American President from Washington to Obama! by Children's History Press
My rating: 5 of 5 stars

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Thursday, February 4, 2016

Book Review - Between the World and Me by Ta-Nehisi Coates

Between the World and Me
I received an Amazon gift coupon for Rs 200 recently, and I began looking for a book to buy. I zeroed in on 'Between the World and Me' by Ta-Nehisi Coates for a few reasons.

One, the book deals with a subject (race) that is at the heart of contemporary social fabric of the US. We wish the country has moved on, but regularly we get to hear of issues and events that only point to the contrary.

Two, the author is a well-known journalist. He works for The Atlantic.

Three, this book, his second, is a very recent one, and the news of its publication is fresh in memory.

The book is in the form of a letter to his 14-year old son, about what it means to be black in the US. Apparently, the book came about after Coates asked his editor why no one wrote like James Baldwin (whose The Fire Next Time, is in the form of a letter), and the editor told him to give it a try.

Drawing a lot from his childhood in Baltimore and many other personal experiences, Coates brilliantly paints a haunting picture of violence. References to brutality are powerful enough to linger in our minds for long. He constantly refers to the body that is always under the threat of being harmed, his feelings of being in a country that has been built by whites with the labour of blacks.

I haven't been in the US long enough to know first hand how race relations play out in everyday lives. I have heard both versions: one, that the country has moved far, far ahead from where it was once; and two, there is still lot of racial ill-will among the whites for the Afro-Americans. Segregation may not legally exist, but in reality it does still, if not so much on the ground, definitely in the mind.

The book paints a very pessimistic picture: almost tells you there is just no hope of anything getting better. I got a feeling that he was going on and on. The bleak tenor was off-putting. One shouldn't be taking so much pains to explain and convince why something will not improve; it should be for the contrary, why there is still reason for hope.

Nevertheless, Coates's autobiographical accounts and his arguments on why he doesn't see much hope, is a good read, giving us a frame of reference to understand the complex topic of race relations in the US.

Between the World and Me by Ta-Nehisi Coates
My rating: 3 of 5 stars

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Tuesday, February 2, 2016

Interesting US presidential poll season ahead

So it's Ted Cruz and Bernie Sanders who are hogging limelight after the Iowa caucuses yesterday.

On the Republican side, while I can understand the sentiments that are bringing in the numbers for Donald Trump, his radical thoughts are unnerving. Between the two, Cruz is preferable.

On the Democratic side, my choice is Hillary, mainly because of her overall career record and experience. Bernie Sanders isn't appealing. He is talking of a policy line that is far too Leftist that one can imagine would work in the US. Barack Obama's policies themselves weren't going down well.

This US presidential poll is promising to be very exciting.