Emails Over Radio

The modern cellular network is a marvel of technological advancement that we often take for granted now. With 5G service it’s easy to do plenty of things on-the-go that would have been difficult or impossible even with a broadband connection to a home computer two decades ago. But it’s still reliant on being close to cell towers, which isn’t true for all locations. If you’re traveling off-grid and want to communicate with others, this guide to using Winlink can help you send emails using a ham radio.

While there are a number of ways to access the Winlink email service, this guide looks at a compact, low-power setup using a simple VHF/UHF handheld FM radio with a small sound card called a Digirig. The Digirig acts as a modem for the radio, allowing it to listen to digital signals and pass them to the computer to decode. It can also activate the transmitter on the radio and send the data from the computer out over the airwaves. When an email is posted to the Winlink outbox, the software will automatically send it out to any stations in the area set up as a gateway to the email service.

Like the cellular network, the does rely on having an infrastructure of receiving stations that can send the emails out to the Winlink service on the Internet; since VHF and UHF are much more limited in range than HF this specific setup could be a bit limiting unless there are other ham radio operators within a few miles. This guide also uses VARA, a proprietary protocol, whereas the HF bands have an open source protocol called ARDOP that can be used instead. This isn’t the only thing these Digirig modules can be used for in VHF/UHF, though. They can also be used for other digital modes like JS8Call, FT8, and APRS.

Continue reading “Emails Over Radio”

Soldering The Elusive USB C Port

Many SMD components, including some USB C ports, have their terminals under the component. When installed, the pins are totally hidden. So, how do you solder or unsolder them? That’s the problem [Learn Electronics Repair] encountered when fixing a Lenovo Yoga, and he shows us his solution in the video below.

He showed the removal in a previous video, but removal is a bit easier since you can just heat up the area, yank the connector, and then clean up the resulting mess at your leisure. Installation is harder because once the socket is down, you no longer have access to the pads.

Continue reading “Soldering The Elusive USB C Port”

Double-Checking NASA’s Eclipse Estimate At Home

If you were lucky enough to be near the path of totality, and didn’t have your view obscured by clouds, yesterday’s eclipse provided some very memorable views. But you know what’s even better than making memories? Having cold hard data to back it up.

Hackaday contributor [Bob Baddeley] was in Madison, Wisconsin for the big event, which NASA’s Eclipse Explorer website predicted would see about 87% coverage. Watching the eclipse through the appropriate gear at the local hackerspace was fun, but the real nerding out happened when he got home and could pull the data from his solar system.

A graph of the system’s generated power shows a very clear dip during the duration of the eclipse, which let him determine exactly when the occlusion started, peaked, and ended.

Continue reading “Double-Checking NASA’s Eclipse Estimate At Home”

On Cloud Computing And Learning To Say No

Do you really need that cloud hosting package? If you’re just running a website — no matter whether large or very large — you probably don’t and should settle for basic hosting. This is the point that [Thomas Millar] argues, taking the reader through an example of a big site like Business Insider, and their realistic bandwidth needs.

From a few stories on Business Insider the HTML itself comes down to about 75 kB compressed, so for their approximately 200 million visitors a month they’d churn through 30 TB of bandwidth for the HTML assuming two articles read per visitor.

This comes down to 11 MB/s of HTML, which can be generated dynamically even with slow interpreted languages, or as [Thomas] says would allow for the world’s websites to be hosted on a system featuring single 192 core AMD Zen 5-based server CPU. So what’s the added value here? The reduction in latency and of course increased redundancy from having the site served from 2-3 locations around the globe. Rather than falling in the trap of ‘edge cloud hosting’ and the latency of inter-datacenter calls, databases should be ideally located on the same physical hardware and synchronized between datacenters.

In this scenario [Thomas] also sees no need for Docker, scaling solutions and virtualization, massively cutting down on costs and complexity. For those among us who run large websites (in the cloud or not), do you agree or disagree with this notion? Feel free to touch off in the comments.

In A Twist, Humans Take Jobs From AI

Back in the 1970s, Rockwell had an ad that proudly proclaimed: “The best electronic brains are still human.” They weren’t wrong. Computers are great and amazing, but — for now — seemingly simple tasks for humans are out of reach for computers. That’s changing, of course, but computers are still not good at tasks that require a little judgment. Suppose you have a website where people can post things for sale, including pictures. Good luck finding a computer that can reliably reject items that appear to be illegal or from a business instead of an individual. Most people could easily do that with a far greater success rate than a computer. Even more so than a reasonable-sized computer.

Earlier this month, we reported on Amazon stepping away from the “just walk out” shopping approach. You know, where you just grab what you want and walk out and they bill your credit card without a checkout line. As part of the shutdown, they revealed that 70% of the transactions required some human intervention which means that a team of 1,000 people were behind the amazing technology.

Humans in the Loop

That’s nothing new. Amazon even has a service called Mechanical Turk that lets you connect with people willing to earn a penny a picture, for example, to identify a picture as pornographic or “not a car” or any other task you really need a human to do. While some workers make up to $6 an hour handling tasks, the average worker makes a mere $2 an hour, according to reports. (See the video below to see how little you can make!) The name comes from an infamous 200-year-old chess-playing “robot.” It played chess as well as a human because it was really a human hiding inside of it.

Continue reading “In A Twist, Humans Take Jobs From AI”

Adjustable Lights Help Peer Inside Chips With IR

If you’re used to working through a microscope, you’ve probably noticed that the angle of the light greatly affects how your workpiece looks. Most of us prefer the relatively flat lighting provided by a ring light, but variable angle side lighting can be useful too, especially when you’re peering inside ICs to make sure the silicon is what it’s supposed to be.

That’s what [Bunnie] is working on these days with his Project IRIS, short for “Infrared in situ,” a non-destructive method for looking inside chip packages. The technique relies on the fact that silicon is transparent to certain wavelengths of light, and that some modern IC packages expose the underside of the silicon die directly to the outside world. Initial tests indicated that the angle of the incident IR light was important to visualizing features on the metal interconnects layered onto the silicon, so [Bunnie] designed a two-axis light source for his microscope. The rig uses curved metal tracks to guide a pair of IR light sources through an arc centered on the focal point of the microscope stage. The angle of each light source relative to the stage can be controlled independently, while the whole thing can swivel around the optical axis of the microscope to control the radial angle of the lighting.

The mechanism [Bunnie] designed to accomplish all this is pretty complex. Zenith angle is controlled by a lead screw driving a connecting rod to the lights on their guide tracks, while the azimuth of the lights is controlled by a separate motor and pulley driving a custom-built coaxial bearing. The whole optical assembly is mounted on a Jubilee motion platform for XYZ control. The brief videos below show the lights being put through their paces, along with how changing the angle of the light affects the view inside a chip.

Continue reading “Adjustable Lights Help Peer Inside Chips With IR”

Bye Bye Green Screen, Hello Monochromatic Screen

It’s not uncommon in 2024 to have some form of green background cloth for easy background effects when in a Zoom call or similar. This is a technology TV and film studios have used for decades, and it’s responsible for many of the visual effects we see every day on our screens. But it’s not perfect — its use precludes wearing anything green, and it’s very bad at anything transparent.

The 1960s Disney film makers seemingly had no problem with this as anyone who has seen Mary Poppins will tell you, so how did they manage to overlay actors with diaphanous accessories over animation? The answer lies in an innovative process which has largely faded from view, and [Corridor Crew] have rebuilt it.

Green screens, or chroma key, to give the effect its real name, relies on the background using a colour not present in the main subject of the shot. This can then be detected electronically or in software, and a switch made between shot and inserted background. It’s good at picking out clean edges between green background and subject, but poor at transparency such as a veil or a bottle of water. The Disney effect instead used a background illuminated with monochromatic sodium light behind the subject illuminated with white light, allowing both a background and foreground image to be filmed using two cameras and a dichroic beam splitter. The background image with its black silhouette of the subject could then be used as a photographic stencil when overlaying a background image.

Sadly even Disney found it very difficult to make more than a few of the dichroic prisms, so the much cheaper green screen won the day. But in the video below the break they manage to replicate it with a standard beam splitter and a pair of filters, successfully filming a colourful clown wearing a veil, and one of them waving their hair around while drinking a bottle of water. It may not find its way back into blockbuster films just yet, but it’s definitely impressive to see in action.

Continue reading “Bye Bye Green Screen, Hello Monochromatic Screen”