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.
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.
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.
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.
In recent years you’ve probably seen a couple of photos of tablets and smartphones strapped to the armor of soldiers, especially US Special Forces. The primary app loaded on most of those devices is ATAK or Android Tactical Assault Kit. It allows the soldier to view and share geospatial information, like friendly and enemy positions, danger areas, casualties, etc. As a way of working with geospatial information, its civilian applications became apparent, such as firefighting and law-enforcement, so CivTAK/ATAK-Civ was created and open sourced in 2020. Since ATAK-Civ was intended for those not carrying military-issued weapons, the acronym magically become the Android Team Awareness Kit. This caught the attention of the open source community, so today we’ll dive into the growing TAK ecosystem, its quirks, and potential use cases.
Tracking firefighting aircraft in 3D space using ADS-B (Credit: The TAK Syndicate)
While you’d be hard pressed to find a Hackaday writer that feels any nostalgia for the DRM nonsense the iPod helped to introduce, we’ve got to admit that we miss that click wheel. Spinning your way through long lists was a breeze, and the tactile response made it easy to stop exactly where you wanted. These days, we’re stuck fumbling our way through touch screen interfaces that make simple tasks like seeking to a particular spot in a song or video all but impossible to do with any kind of accuracy.
If you too yearn to once again feel that subtle thumping under your thumb, then check out this project from [landonr]. Technically the handheld gadget is intended to be used as a wireless remote for a home automation system powered by ESPHome, but that’s only one possible application for this particular combination of off-the-shelf components.
If you must, there’s a version with buttons.
Building your own version of the handheld device is a simple as mounting a LILYGO ESP32 T-Display TTGO, an ANO Rotary Navigation Encoder from Adafruit, and a battery pack to a scrap of perfboard. We’d probably look into 3D printing a case to make it a bit less…pokey, but that’s up to you. The result actually bears quite a resemblance to Apple’s iconic media player, but without that pesky walled garden to hold you back.
As mentioned previously, [landonr] wrote the firmware with the intention of controlling a home automation system. So there’s a lot of stuff in there about turning on lights and such. But there are also functions for media playback that look very promising. Whatever software you end up running on it, one thing is for sure: running through the menus is going to feel like a dream.
Although water is often scarce for human consumption and agriculture, this planet is three-quarters covered by the stuff. The problem is getting the salt out, and this is normally done by the Earth’s water cycle, which produces rain and similar phenomena that replenish the amount of fresh water. Roughly 3% of the water on Earth is fresh water, of which a fraction is potable water.
Over the past decades, the use of desalination has increased year over year, particularly in nations like Saudi Arabia, Israel and the United Arab Emirates, but parched United States states such as California are increasingly looking into desalination technologies. The obvious obstacles that desalination faces – regardless of the exact technology used – involve the energy required to run these systems, and the final cost of the produced potable water relative to importing it from elsewhere.
Other issues that crop up with desalination include the environmental impact, especially from the brine waste and conceivably marine life sucked into the intake pipes. As the need for desalination increases, what are the available options to reduce the power needs and environmental impact?
