Smart Ruler Has Many Features

December 2, 2021 by Bryan Cockfield 12 Comments

For those of us who remember old ball mice, they were a lot like modern optical mice except that they needed to be cleaned constantly. Having optical mice as a standard way of interacting with a computer is a major improvement over previous eras in computing. With extinction of the ball mouse, there are an uncountable number of cheap optical mice around now which are easy pickings for modern hacking, and this latest project from [Vipul] shows off some of the ways that optical mice can be repurposed by building a digital ruler.

The build seems straightforward on the surface. As the ruler is passed over a surface the device keeps track of exactly how far it has moved, making it an effective and very accurate ruler. To built it, the optical component of a mouse was scavenged and mated directly to a Raspberry Pi Zero W over USB. Originally he intended to use an ESP32 but could not get the USB interface to work. [Vipul] was then able to write some software which can read the information from the mouse’s PCB directly and translate it into human-readable form where it is displayed on a small screen. The entire device is housed in a custom 3D-printed enclosure to wrap everything up, but the build doesn’t stop there though. [Vipul] also leveraged the Bluetooth functionality of the Pi and wrote a smartphone app which can be used to control the ruler as well.

While the device does have some limitations in that it has to make contact with the object being measured across its entire length, there are some situations where we can imagine something like this being extremely useful especially when measuring things that aren’t a straight line. [Vipul] has also made all of the code for this project publicly available for those of us who might have other uses in mind for something like this. We’ve seen optical mice repurposed for all kinds of things in the past, too, including measuring travel distances in autonomous vehicles.

Continue reading “Smart Ruler Has Many Features” →

Broadband Across The Congo

September 20, 2021 by Al Williams 34 Comments

If you live in much of the world today, high-speed Internet is a solved problem. But there are still places where getting connected presents unique challenges. Alphabet, the company that formed from Google, details their experience piping an optical network across the Congo. The project derived from an earlier program — project Loon — that used balloons to replace traditional infrastructure.

Laying cables along the twisting and turning river raises costs significantly, so a wireless approach makes sense. Connecting Brazzaville to Kinshasa using optical techniques isn’t perfect — fog, birds, and other obstructions don’t help. They still managed to pipe 700 terabytes of data in 20 days with over 99.9% reliability.

Continue reading “Broadband Across The Congo” →

Vintage Monochromator Makes Monochromatic Light, Mechanically

July 27, 2021 by Donald Papp 25 Comments

A monochromator is an optical instrument that permits only a narrow selection of wavelengths to be transmitted from a source, and the particular model [Doug] obtained renders visual light monochromatic by way of a mechanically-adjusted system of mirrors and diffraction gratings that allows only the selected wavelength to pass. The big dial is how the operator selects the desired wavelength, and is labeled in ‘mu’ (or milli-micro), but [Doug] helpfully points out the more modern term for that is nanometers.

LCD monitor viewed through a monochromator set to pass red wavelength only, showing that images remain intact.

How does it work? Light enters the device via an opening at the base, and only the selected wavelength exits from the top. The dial’s range is from 450 nm to 640 nm (representing violet-blue to red), which [Doug] demonstrates by shining a white LED flashlight into the unit and showing how only green, red, or blue will exit from the top depending on the setting of the dial.

An interesting side note is that with this particular device, images can be rendered monochromatic but otherwise remain intact. [Doug] demonstrates this by viewing a small section of his LCD monitor through the device, as shown in the photo he managed to capture.

It’s an interesting piece of vintage equipment that shows what is possible with passive optical components and a clever mechanical design. These devices are therefore entirely manually-operated tools (at least until someone sticks a stepper motor to the adjustment dial to create an automated scanner, that is.)

This Expedient Microfiche Reader Illuminates Retro Datasheets

December 20, 2020 by Dan Maloney 22 Comments

You have to be of a certain vintage to remember doing research on microfilm and microfiche. Before the age of mass digitization of public records, periodicals, and other obscure bits of history, dead-tree records were optically condensed onto fine-grain film, either in roll form or as flat sheets, which were later enlarged and displayed on a specialized reader. This greatly reduced the storage space needed for documents, but it ended up being a technological dead-end once the computer age rolled around.

This was the problem [CuriousMarc] recently bumped into — a treasure trove of Hewlett-Packard component information on microfiche, but no reader for the diminutive datasheets. So naturally, he built his own microfiche reader. In a stroke of good luck, he had been gifted a low-cost digital microscope that seemed perfect for the job. The scope, with an HD camera and 5″ LCD screen, was geared more toward reflective than transmissive use, though, so [Marc] had trouble getting a decent picture of the microfiches, even with a white paper backing.

Version 2.0 used a cast-off backlight, harvested from a defunct DVD player screen, as a sort of light box for the stage of the microscope. It was just about the perfect size for the microfiches, and the microscope was able to blow up the tiny characters as well as any dedicated microfiche reader could, at a fraction of the price. Check out the video below for details on the build, as well as what [Marc] learned from the data sheets about his jackpot of HP parts.

With the wealth of data stored on microforms, we’re surprised that we haven’t seen any readers like this before. We have talked about microscopic wartime mail, though.

Continue reading “This Expedient Microfiche Reader Illuminates Retro Datasheets” →

Skylight In Any Room

October 4, 2020 by Brian McEvoy 41 Comments

Despite a glut of introvert memes, humans need sunlight. If vitamin D isn’t your concern, the sun is a powerful heater, and it helps plants grow. Sadly for [mime], their house is not positioned well to capture all those yummy sunbeams. Luckily for us, their entry into the 2020 Hackaday Prize is their sun-tracking apparatus that redirects those powerful rays throughout the house. It uses a couple of mirrors to redirect the light around their shed and into the house. For those who work in a dim office, no amount of work is too great for a peek of natural sunlight.

Movie spoiler alert: We saw this trick in the 1985 movie Legend and it was enough to vanquish the Lord of Darkness.

This project started in 2014 and sat on hiatus for more than five years, but it is back and prime for improvements fueled by half-a-decade of experience. The parts that aren’t likely to change are the threaded struts that adjust the positioning mirror’s angle, the driving motors, and power circuitry. Their first plan was to build a solar-powered controller with an Arduino, DC motors, and sun telemetry data, but now they’re leaning toward stepper motors and a computer in the house with a long cable. They are a finalist this year, so we will keep our eyes peeled for further development.

High Speed The Way We Want It

June 15, 2020 by Inderpreet Singh 26 Comments

The one thing we have learned over the current pandemic is that we need the internet, and the faster the better. Though cost is surely a hurdle, the amount of bandwidth available has its bottlenecks rooted from the underlying technology. Enter new technology from an Australian Research team who have claimed to have field tested internet speeds as fast at 44.2 terabits per second.

The breakthrough in bandwidth is attributed to a new optical chip that employs optical frequency combs or micro-comb, and has been published by [Corcoran et al] of Monash University. The team exploits the ability of certain crystals to create resonant optical fields called solitons and these form highly efficient optical transmission system. For the uninitiated, optical frequency combs are an optical spectrum of equidistant lines whose values if fixed, can be used to measure unknown frequencies. The original discovery earned Roy J. Glauber, John L. Hall and Theodor W. Hänsch the Nobel Prize in Physics in 2005, and though it is a relatively new field it has seen a lot of activity in the research community.

The experimental setup has a resonator with a free spectral range spacing of 48.9GHz, and from the generated optical fields or lines, 80 were selected. Using a side-band modulator the bands were doubled and eventually with 64 QAM modulation facilitated a symbol rate of 23 Gigabaud. Now at this point, the paper says that this experiment is still an under-utilization of the available resources. The extra connectivity speed may be helpful in gaming and streaming but we will be needing faster drives to get our emails attachments downloaded faster. If you are inspired and want to play with lasers and optical communications, check out the DIY Laser Optical Link.

Thanks [Anil Pattni] for the tip.

How Does Starlink Work Anyway?

February 20, 2020 by Dan Maloney 128 Comments

No matter what you think of Elon Musk, it’s hard to deny that he takes the dictum “There’s no such thing as bad publicity” to heart. From hurling sports cars into orbit to solar-powered roof destroyers, there’s little that Mr. Musk can’t turn into a net positive for at least one of his many ventures, not to mention his image.

Elon may have gotten in over his head, though. His plan to use his SpaceX rockets to fill the sky with thousands of satellites dedicated to providing cheap Internet access ran afoul of the astronomy community, which has decried the impact of the Starlink satellites on observations, both in the optical wavelengths and further down the spectrum in the radio bands. And that’s with only a tiny fraction of the planned constellation deployed; once fully built-out, they fear Starlink will ruin Earth-based observation forever.

What exactly the final Starlink constellation will look like and what impact it would have on observations depend greatly on the degree to which it can withstand regulatory efforts and market forces. Assuming it does survive and gets built out into a system that more or less resembles the current plan, what exactly will Starlink do? And more importantly, how will it accomplish its stated goals?

Continue reading “How Does Starlink Work Anyway?” →