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Showing posts with label LED. Show all posts
Showing posts with label LED. Show all posts

Friday, February 16, 2024

Shuji Nakamora and his (Juliano) Blue Gallium Nitride LED


Lots of great stuff in this video:  

-- They get the charge carrier thing right:  contrary to many presentations, holes don't really move in a semiconductor.  Electrons move to fill holes, making it appear that the holes are moving. 

-- Interesting that Nakamura was so willing to defy company orders for so long. 

-- The description of the discipline that powered his inventiveness is inspiring. 

-- The way he was treated (badly) in Florida because he lacked a PhD is sadly illuminating. 

-- The discussion of corporate infighting is interesting.  

We wrote about Nakamura before:  https://soldersmoke.blogspot.com/2021/02/shuji-nakamura-inventor-of-juliano-blue.html


Sunday, April 11, 2021

RIP Isamu Akasaki -- Shared Nobel Prize for LED -- Analog Guy


From the obituary in the Washington Post: 

In addition to the Nobel Prize, Dr. Akasaki’s honors included a 2009 Kyoto Prize — Japan’s highest honor — recognizing developments in advanced technology. He found that some technology, however, needed no advancing at all. He took great pleasure, for example, in long-playing classical music records.

On that point, he joked, “I am analog.”

Wednesday, February 3, 2021

Shuji Nakamura -- The Inventor of Juliano Blue LEDs

He is the 2014 winner of the Nobel Prize for Physics.   He is the person who figured out how to make blue light LEDs through the use of an Indium Gallium Nitride semiconductor.  I was reading about him this morning in "Conquering the Electron" by Derek Cheung and Eric Brach.  Thanks to Nakamura, the numerals on all my frequency displays glow in a pleasing Juliano blue.  Three cheers for Nakamura! 

More on him here: 

https://www.trumpf.com/en_US/presse/online-magazine/nobel-price-winner-nakamura-wants-more-light/

Monday, September 22, 2014

The SWLing Post, Ears To Our World, and the HumanaLight

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Thomas, K4SWL, has a really impressive shortwave listening blog.  Yesterday he was kind enough to post an article about my latest obsession:  the echoes on China Radio International: 
http://swling.com/blog/ 

Even more impressive is Thomas's work on behalf of poor people in the Third World. He is the Director of Ears to Our World, a charity group that provides innovative, simple and appropriate technologies to schools and communities in remote, rural and impoverished regions of our world.
Here they are: http://www.earstoourworld.org/

They distribute radios to people who would no other regular technological contact with the rest of the world.  They are also involved in an intriguing project called the HumanaLight:  "Dead" AA batteries power lights that can make a big difference for people living in areas that have never been on any grid.   Here it is: http://www.earstoourworld.org/humanalight/

Ears to Our World is looking for Donations to help them bring light and radios to people who really need them:   Here is where you can help: 
http://www.earstoourworld.org/donate

This is clearly a very appropriate charity for radio amateurs. 


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Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Saturday, July 19, 2014

Gravity Light -- A Potential Power Source for QRP Ops in the Field


Nice idea.

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Saturday, May 3, 2014

The Guy who Invented the LED

I'm a big fan of Ira Flatow's "Science Friday" radio program (recommended!)
This week, while digging through the archives, I found this gem:

http://www.sciencefriday.com/segment/10/12/2012/fifty-years-ago-a-bright-idea.html


Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Thursday, December 13, 2012

FITSAT-1 Flashing Morse With LEDs from Orbit


Very cool:  Japanese students sent up a small satellite.  One of its capabilities is to flash Morse code messages in the visible light range using LEDs.   Prepare to peg your geek meter: 
http://www.fit.ac.jp/~tanaka/fitsat.shtml 

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Thursday, October 23, 2008

Lasers, LEDs, Tin-foil Hats, and QRP

Yesterday I got a very interesting message from Rye, K9LCJ. The map of Tasmania comes from the Modulated Light DX portion of the KA7AOI site (below).

Hi Bill:

I really enjoy your Solder Smoke show and news feeds. Great stuff that has got me back into ham radio again. Your note about optical comms got me fired up enough to add some notes that you might not be aware of.

There is a substantial worldwide community playing with optical communications and they have achieved some amazing records using simple off the shelf components – mostly big Luxeon LEDs which have some (debatable) advantages over Lasers. The most sophisticated component in typical systems is the Fresnel lens – which can be obtained at office supply stores or ebay as “page magnifiers” for a couple of bucks.

There seem to be about four major groups:

The Radio and Electronics Association of Southern Tasmania has an active bunch and they have achieved some great distance records with (QRP) LEDs. They have also been bouncing signals off of geographic features to establish communications paths. They are also doing some cloud/sky bounce things that are quite amazing. The REAST web site has lots of well documented test data that’s really interesting to read.

K3PGP has an exceptional web page full of test reports and construction details. His K3PGP preamp/receiver (and variants) are the basic building block for most systems. It uses a $1.00 pin diode, a MPF103 FET and a handful of common parts to get some almost fantastic performance.

Yves, F1AVY has a strong theoretical background and has been doing interesting stuff in France for quite a while and his web page has lots of interesting technical details.

Clint, KA7AOI has a very comprehensive web page. Clint holds the record for long distance communications (173 miles) and describes much of his equipment and testing. There is also a bunch of historical material that is very interesting.

There are probably a bunch of folks I have forgotten, but all of them are noted in the many and varied links found on these web sites.

I think that the most interesting thing about the activities is how the teams have adapted available technology to an interesting problem. Much of the work resembles current amateur weak signal activities. In fact, Spectran and WSJT are part of almost every activity. Much of the work is unique outside of the academic community and might even be called groundbreaking in some areas.

We have a small group here in the Raleigh North Carolina area, but so far we haven’t done anything of note other than build equipment and play in the local park. The fact that this sort of thing must be done outside at night draws all kinds of attention – some of which is not necessarily good. …a bunch of strange looking guys running around in the dark with strange flashing red lights…. I have a special cap that I wear for the occasions.

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Keep up the good work.

Rye Gewalt

K9LCJ

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