Apple’s Satellite Emergency Texts, How Do They Work?

September 9, 2022 by Jenny List 24 Comments

There is always some hype surrounding an Apple product announcement, and while maybe it’s not in the same league as those for the original iPod or iPhone, their iPhone 14 model will include emergency texting by satellite has generated quite a bit of coverage. It’s easy to find a lot about the system from the software end in terms of its interface and even Apple’s use of compression, but what about the radio side? Whose satellite constellation are they using, and how does it work?

As has been widely reported, their communication partner for the service is Globalstar, a provider of satellite data services that like their competitor Iridium have their origins in the 1990s when satellite phones were briefly seen as the Next Big Thing. They have a 24-satellite constellation, and they sell a range of off-the-grid voice, data, paging, tracking, and IoT connectivity services. The Apple emergency texting looks a lot like Globalstar’s Spot texting service. It’s only available in North America for now, we’re guessing because the satellites aren’t smart relays but straightforward transponders, and the network lacks sufficient ground station coverage outside that region.

With all the talk about low-earth-orbit connectivity surrounding services such as SpaceX’s Starlink it’s a bit unexpected to find ourselves back with a satellite constellation using 1990s technology. But we can see that as well as a major win for Globalstar as their service begins to look outdated by comparison to Starlink, it’s a perfect match for Apple in not requiring a complex ground station for low-bandwidth text messages. We expect that there will be some form of exclusivity in the deal, so it will be interesting to see how the larger Android vendors respond.

It’s worth noting, we’ve looked at satellite IoT services before.

Wilderness image: U.S. Fish and Wildlife Service, Public Domain.

Upcycling Flat Scraps With Open Source Tools

September 9, 2022 by Al Williams 6 Comments

If you have any sort of device that cuts like a CNC mill or a laser cutter, you probably generate a lot of strange-looking scrap material. Most of us hate to throw anything away, but how do you plan to use all these odd shapes? [Caddzeus] has an answer. Using a camera and some software he digitizes the shapes accurately into a form usable in his CAD package of choice.

The process involves setting up some targets with known dimensions that will appear in the photograph. This allows the picture to be taken without being overly concerned about the distance to the camera or the angle.

Using GIMP, he adjusts the images to remove the perspective. He then brings the image into Inkscape where he can accurately scale and trace the shape.

There are detailed instructions — including videos — but if you know how to use these tools, you can probably figure it out for yourself. This technique would be useful, too, if you wanted to get an outline of something you intend to mill or cut into your CAD program as a reference. We like to do this with a laser cutter so you can burn the outline of something you are engraving or cutting on a piece of paper before you start and easily align the workpiece to the laser.

Of course, a small part could surrender its image to a conventional scanner and you can use a similar technique to adjust the scale. If you start using Inkscape a lot, you’ll want more plugins. You never know what you might build from some scrap odds and ends.

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Your Car Gets Hot When Left In The Sun. Hot Enough To Cook?

September 8, 2022 by Jenny List 18 Comments

In hot weather, those of us who drive are familiar with the sensation of getting into the car and having it feel like an oven inside. A car is a essentially sealed metal box with large windows, thus on a sunny summer day it has more in common with a greenhouse, and in a heatwave this can become unbearable. But does it get hot enough for cooking? [Julian Lozos] aimed to find out, by cooking Icelandic rúgbrauð using only a 2016 Honda and the California sunshine.

Rúgbrauð is a traditional Icelandic rye bread that’s traditionally cooked by geothermal energy buried in the ground for around a day in proximity to a hot spring. A car dashboard gets pretty hot in a California heatwave, so it’s not unreasonable to expect that it might replicate this environment. He parked the Honda on a street in the sun, placed a pot full of dough on the dashboard, and waited.

The maximum temperature measured was 86.5 C (187 F), but unfortunately the sun didn’t stay high enough to maintain that temperature for the required time. After two days in the car the crust was cooked but the interior was still gooey, so the experiment can’t be said to have been successful. He does make the point though that a less traditional and much thinner loaf using a wide and flat tray might have delivered a better result.

We’re intrigued by this experiment, almost enough to try something like it ourselves were the summer not beginning to wane in these more northerly climes. Have any of you tried cooking in a hot car, or would we need a solar oven? Give us your views in the comments.

Tracking Weather Balloons With SDR

September 8, 2022 by Al Williams 26 Comments

The advent of cheap software-defined radio hardware means that what would have once been an exotic expensive undertaking can now be relatively cheap. [David] notes that using some pretty simple gear, he could track down weather balloons.

The U.S. National Weather Service sends up a large number of radiosondes attached to balloons twice a day. Their job is to measure conditions at high altitudes up to about 30km. Once the balloon gets too high, the pressure inside bursts the balloon, and a small parachute slows the instrument package’s descent back to Earth. [David] wanted to track these down and return them to the NWS for reuse.

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Troubleshooting Barcodes: A Lesson In Critical Thinking

September 8, 2022 by Al Williams 26 Comments

We’ve all been there. Something that is known to work doesn’t work out in the field. But back at home base, it works fine. How do you fix it? Of course, there’s no one right answer to that question, but [Benji York] had a particularly satisfying round of troubleshooting some errant barcodes and even came up with a very creative solution.

Here’s the setup: a customer couldn’t read some barcodes sent from [Benji’s] company. Yet when the bad barcodes returned, they were fine. They looked fine, too. In a Twitter post, [Benji] challenges you to see if you can tell what’s wrong.

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ADSL Router As Effects Pedal

September 8, 2022 by Bryan Cockfield 11 Comments

Moore’s law might not be as immutable as we once though thought it was, as chip makers struggle to fit more and more transistors on a given area of silicon. But over the past few decades it’s been surprisingly consistent, with a lot of knock-on effects. As computers get faster, everything else related to them gets faster as well, and the junk drawer tends to fill quickly with various computer peripherals and parts that might be working fine, but just can’t keep up the pace. [Bonsembiante] had an old ADSL router that was well obsolete as a result of these changing times, but instead of tossing it, he turned it into a guitar effects pedal.

The principle behind this build is that the router is essentially a Linux machine, complete with ALSA support. Of course this means flashing a custom firmware which is not the most straightforward task, but once the sound support was added to the device, it was able to interface with a USB sound card. An additional C++ program was created which handles the actual audio received from the guitar and sound card. For this demo, [Bonsembiante] programmed a ring buffer and feeds it back into the output to achieve an echo effect, but presumably any effect or a number of effects could be programmed.

For anyone looking for the source code for the signal processing that the router is now performing, it is listed on a separate GitHub page. If you don’t have this specific model of router laying around in your parts bin, though, there are much more readily-available Linux machines that can get this job done instead.

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A device with pipes and pumps sitting next to a body of water

Hackaday Prize 2022: Otter Force One Protects Kelp Forests By Sucking Up Sea Urchins

September 8, 2022 by Robin Kearey 10 Comments

When thinking about forests being endangered by human activity, most people would immediately think of the rainforest. Below the ocean surface, there’s another type of forest is in danger: the kelp forests off the coast of northern California. Warming sea water has triggered an explosion in the population of purple sea urchins (Strongylocentrotus purpuratus) which devour kelp at an alarming rate. It’s estimated that 90% of kelp forests have been lost to the urchins along a 350 km stretch of coastline.

The fix is as simple as getting rid of the urchins, but collecting the millions of spiny creatures manually isn’t realistic. Luckily, [RobotGrrl] designed just the tool for this task: Otter Force One, an autonomous underwater robot that can gather the aquatic interlopers and put them in a bag for removal. The device is still under development, but progress so far has been promising. The basic idea is to identify an urchin using machine vision, then dislodge it with a water jet, and finally to use a suction pump to pull it inside the machine and store it in a bag.

A prototype made from 3D printed components is currently being used to test the idea. Its motors are driven by an ESP32 with a motor controller, with the system powered by a set of beefy lithium batteries. Tests with plastic urchin models confirm that the suction mechanism works, though the water jet and machine vision systems still need to be tested. But even without these in place the Otter Force One can still be used by human divers to improve their urchin-gathering efficiency.

We’ll definitely keep an eye on this project, and hopefully see it evolve into a fully-automated urchin hunter. Underwater pest-control robots are not completely new: we already saw a laser-powered delouser for use on salmon farms. There are also robotic starfish and octopuses.