A Ball Lens For Optical Fiber Coupling On The Cheap

It’s fair to say that for most of us, using a fiber optic cable for digital audio or maybe networking will involve the use of an off-the-shelf termination. We snap the cable into the receptacle, and off we go. We know that inside there will be an LED and some lenses, but that’s it. [TedYapo] though has gone a little further into the realm of fibers, by building his own termination. Faced with the relatively high cost of the ball lenses used to focus light from an LED into the end of the fiber he started looking outside the box. He discovered that spherical glass anti-bumping balls used when boiling fluids in laboratories make an acceptable and much cheaper alternative.

A ball lens has an extremely short focal length, meaning that this same property which allowed Antonie van Leeuwenhoek to use them in his microscopes is ideal for LED focusing in a small space at the end of a fiber. Chromatic aberrations are of no consequence for light of a single wavelength. It seems that the glass balls are uniformly spherical enough to do the job. Fitted with the LED and fiber termination in a 3D-printed block, the relative position of the ball can be controlled for optimum light transfer. It’s a relatively simple hack mentioned in passing in a Twitter thread, but we like it because of its cheapness and also for an insight into the world of optical fiber termination.

Curious to know more about optical fibers? We covered just the video for you back in 2011.

German Experiment Shows Horses Beating Local Internet Connections

These days, we’re blessed with wired and wireless networks that can carry huge amounts of data in the blink of an eye. However, some areas are underprovisioned with bandwidth, such as Schmallenberg-Oberkirchen in Germany. There, reporters ran a test last December to see which would be faster: the Internet, or a horse?

The long and the short of it is that Germany faces issues with disparate Internet speeds across the country. Some areas are well-served by high-speed fiber services. However, others deemed less important by the free market struggle on with ancient copper phone lines and subsequently, experience lower speeds.

Thus, the experiment kicked off from the house of photographer [Klaus-Peter Kappest], who started an Internet transfer of 4.5GB of photos over the Internet. At the same time, a DVD was handed to messengers riding on horseback to the destination 10 kilometers away. The horses won the day, making the journey in about an hour, while the transfer over [Kappest’s] copper connection was still crawling along, only 61% complete.

Obviously, it’s a test that can be gamed quite easily. The Internet connection would have easily won over a greater distance, of course. Similarly, we’ve all heard the quote from [Andrew Tanenbaum]: “Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway.”

Notably, [Kappest’s] home actually had a fiber line sitting in the basement, but bureaucracy had stymied any attempts of his to get it connected. The stunt thus also served as a great way to draw attention to his plight, and that of others in Germany suffering with similar issues in this digital age.

Top speeds for data transfer continue to rise; an Australian research team set a record last year of 44.2 terabits per second. Naturally, the hard part is getting that technology rolled out across a country. Sound off below with the problems you’ve faced getting a solid connection to your home or office.

Lightwave Multimeter Teardown

You tend to think of test equipment in fairly basic terms: a multimeter, a power supply, a signal generator, and an oscilloscope. However, there are tons of highly-specialized test equipment for very specific purposes. One of these is the 8163A “lightwave multimeter” and [Signal Path] tears one part for repair in a recent video that you can see below.

If you’ve never heard of a lightwave multimeter, don’t feel bad. The instrument is a measuring system for fiber optics and, depending on the plugins installed, can manage a few tests that you’d usually use an optical power meter, a laser or light source, and some dedicated test jigs to perform. Continue reading “Lightwave Multimeter Teardown”

A Brief History Of Optical Communication

We live in the information age where access to the internet is considered a fundamental human right. Exercising this right does largely rely on the technological advances made in optical communication. Using light to send information has a long history: from ancient Greece, through Claude Chappe’s semaphore towers and Alexander Graham Bell’s photophone, to fiber optic networks and future satellite internet constellations currently developed by tech giants.

Let’s dive a little bit deeper into the technologies that were used to spread information with the help of light throughout history. Continue reading “A Brief History Of Optical Communication”

Experiment With SFP Modules With This Handy Breakout

While most home networking hardware comes with network ports baked in from the factory, industrial grade gear is typically more versatile. Using standards like Small Form-factor Pluggable, or SFP, network switches can be used with a variety of transport mediums by simply swapping tranceivers in and out. These network devices typically handle the nitty gritty of transmitting Ethernet over fiber optics, and for those keen to experiment, this breakout may come in handy.

The board design comes complete with an SFP receptacle, allowing a variety of compatible receivers to be plugged in for experimentation. With the standard using differential signalling, the board carries hardware to allow the transceiver to be fed with single-ended signals instead, though a differential version is available too. The board can be used for transmitting different signals over fiber, outside just Ethernet, or used as a simple way to reprogram SFP modules via I2C. The latter can be useful to get around DRM in network switches that attempt to lock out generic transceiver modules.

It’s a useful piece of hardware for the fiber optic tinkerer and network admin alike. You might also find it useful if you’re building your own 10-gigabit network at home!

Fiber Optics, But… Wetter?

Fiber optics are a great way to transfer huge quantity of data at lightning speed. Thanks to the property of total internal reflection, which allows light to flow through a glass fiber like fluid through a pipe, they can be used for communications at long distances and form the backbone of modern communication networks. However, water is also able to pull off the total internal reflection party trick, and [Mike Kohn] decided to see if it could be used as a communication medium, too.

The experimental setup consists of an ATTiny85 that receives signals over its serial port, and outputs the received bits by flashing an LED. This LED is attached to a plastic tube filled with water. On the receiving end, another ATTiny85 reads the voltage level of a photodiode placed in the other end of the tube. When the ADC detects voltage over a certain level, it toggles a pin connected to the serial RX pin.

Hooking the setup to a pair of terminals, [Mike] was able to successfully transmit 9600 baud serial data through a tube full of water with just an LED and a small microcontroller. To verify the success, he ran the test again with an air-filled tube instead, which failed. In doing so, he proved that the water was doing the work.

We’ve seen other optical data hacks, too – like this awesome laser ethernet build. Video after the break.

Continue reading “Fiber Optics, But… Wetter?”

Fiber Optic Ceiling Pumps To The Beat

For years [Centas] dream was to take the stars to his home and build a fiber optic ceiling. Even though there are many fiber optic star ceiling kits commercially available, we are glad he decided to go full DIY on this project as the result is simply astonishing.

[Centas] chose to make a model of a section of the sky as it is visible from his home and generated a map of 1,200 stars with the planetarium software Celestia. The most time-consuming part of making a star ceiling is always poking lots of holes for the fibers. In [Cenas] case this turned out to be especially cumbersome as he decided to install the fibers after hanging the ceiling panel so he came up with a method to catch the fiber with a fishing pole after pushing it through from the bottom. The finished ceiling looks really great though with its rounded edges that contain RGB LED strips for side illumination. [Cenas] also painted the ceiling after installing the fibers so they are not visible when they are not lit but there is still enough light shining through the paint.

Continue reading “Fiber Optic Ceiling Pumps To The Beat”