The Engineering Guy explains fiber optics

engineering_guy_fiber_optics

[Bill the “Engineer Guy” Hammack] is back with another lesson in the science behind the technology we know and love, but might not fully understand. This time around he discusses fiber optic cabling and how it is used to relay data across distances both small and large.

He starts off by showing how laser light can be easily transmitted from one end of an audio-grade fiber optic cable to the other. To show us how this is accomplished, he sets up a simple table top demonstration involving a bucket, some propylene glycol, and a green laser pointer. The bucket has been modified to include a clear window at one side and a spout at the other. The laser is carefully lined up, and when the spout is unplugged, a steady stream of propylene glycol is released into a second bucket. As [Bill] explains, the laser stays within the stream of fluid due to total internal reflection, and can be seen shining in the second bucket.

[Bill] also discusses how fiber optics were employed in the first transatlantic telecommunications cable, as well as how pulse code modulation was used to send analog voice data over the undersea digital link.

As always, [Bill’s] video is as entertaining as it is enlightening, so be sure to check it out below.

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[Dino] celebrates the 131st anniversary of the Photophone

photophone_demonstration

[Dino Segovis] wrote in to share yet another installment of his Hack a Week series, though this one is quite timely.

It was 131 years ago today that [Alexander Graham Bell] unveiled the Photophone to the world. A precursor to fiber optic technology, [Bell’s] incredibly important invention can be easily replicated in your garage, as [Dino] shows us.

The original Photophone was constructed using a megaphone and crystalline selenium cells at the focal point of the receiver, however this version can be made with easy to obtain parts. [Dino] rigged his laptop up to a speaker on which he mounted a mirror, before setting it out in the sun. The vibrations of the mirror modulate the sunlight, reflecting it onto a solar cell positioned at the end of a long, black PVC tube. The solar cell’s leads are fed into an amplifier followed by a speaker, which broadcasts the audio.

The demonstration goes off without a hitch, and while some might be underwhelmed by the technolgy, imagine how incredible it would have looked 131 years ago!

Hackaday links: April 10, 2011

Sunlit LCD screen

[A.J.] did some experiments and managed to replace his LCD backlight using fiber optics and the sun.

Game Boy LCD Repair

[Alan] found that he could fix dead columns on his Game Boy LCD screen with a little reflow work on the connector.

3DS Design Flaw?

Anyone having problems with the way their Nintendo 3DS closes? [Jeroen] noticed that his screen touches the other half of the device when closed. He added rubber feet to protect it, but we wonder if anyone else has noticed this issue?

Mac TP dispenser

This one takes iLife to a new level. Never poop without Apple’s consent again thanks to this Macintosh toilet paper dispenser. [Thanks Rob]

Children are the future

Here’s a heart warming way to end; [Bret] is teaching his 5-year-old son to solder. There’s a video that is sure to put a smile on your face. You’ll remember [Bret] (aka [FightCube]) from the adjustable prank box, a few 555 timer contest submissions, and several other hacks. We expect big things from your progeny!

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