There was a time when it was easy to eavesdrop on police and other service radio networks. Police scanners fans can hear live police, fire, and ambulance calls. However, it isn’t as easy as it used to be because nearly all radios now are trunked. That means conversations might jump from channel to channel. However, P25 can unscramble trunked radio calls intercepted by a cheap SDR dongle and let you listen in. [SignalsEverywhere] shows you how to set it up for Windows or Linux and you can see the video below.
Trunking radio makes sense. In the old days, you might have a dozen channels for different purposes. But most channels would be empty most of the time. With trunking radio, a radio’s computer is set to be in a talk group and a control channel sorts out what channel the talk group should use at any given time. That means that one channel might have several transmissions in a row from different talk groups and one talk group might hop to a new channel on each transmission.
[splat238] had a ton of spare sensors laying around that he had either bought for a separate project or on an impulse buy, so he knew he had to do something with them. He decided to build his own digital multi-tool focusing on sensors that would be particularly useful in a workshop setting. Coincidentally, he was inspired by a previous hack that we covered a while back.
He’s equipped his device with a bubble level, tachometer, IR thermometer, protractor, laser pointer, and many, many more features that would make great additions to any hacker’s workspace. There’s a good summary of each sensor, making his Instructable somewhat of a quick guide to common sensing modalities for hardware designers. The tachometer, thermometer, laser pointer, and a few other capabilities are notable upgrades from the project we highlighted previously. We also appreciate the bigger display, allowing for more detailed user feedback particularly in using the compass and bullseye digital level among other features.
The number of components in [splat238’s] build is too extensive to detail one-by-one in this article, so please see his Instructable linked above for all the details. [splat238] made his own PCB for mounting each sensor and did a good job making the design modular so you wouldn’t need to add certain components if you don’t need them. Most of the components take some through-hole soldering with only a handful of 0805 resistors required otherwise. The housing was designed such that the user can handle the tool with one hand and can switch between each function with a push of a button.
Finally, the device is powered using a rechargeable lithium-polymer battery making it very reusable. And, if there weren’t enough features already, the battery can be charged via USB or through two solar panels mounted into the housing unit. Okay, solar charging might be a case of featuritis, but still a cool build either way.
Over the past few months we’ve heard a lot about contact tracers which are designed to inform users if they’ve potentially come into close proximity with someone who has the virus. Generally these systems have been based on smartphone applications, but there are also hardware solutions that can operate independently for those who are unable or unwilling to install the software. Which is precisely what [Tom Bensky] has implemented using an ESP32 and a USB battery bank.
The idea is simple: the software generates a unique ID which is broadcast out by the ESP32 over Bluetooth Low Energy. Appended to that ID is a code that indicates the person’s current physical condition. There’s no centralized database, each user is expected to update their device daily with any symptoms they may be experiencing. If your tracker is blinking, that means somebody has come in close enough proximity that you should look at the collected data and see how they were feeling at the time.
It’s not a perfect system, of course, as for one thing the number of people that are willing and able to flash this firmware onto a spare ESP32 and carry the thing around with them all day is going to be extremely small. This might have filled an interesting niche if we were still going to hacker and maker cons this summer, but all of those have gone virtual anyway. That said, it’s an interesting look at how a decentralized contact tracing system can be implemented cheaply and quickly.
Another detail worth taking a look at is how [Tom] handled the user experience in his firmware. In an effort to make the tracer as easy as possible to configure, he’s using the Web Bluetooth capability of Google Chrome. Just open up the local web page in your browser, and it will handle talking to the hardware for you. Even if you’re not in the market for a contract tracer, we think this is a great example for how to handle end-user configuration on the ESP32.
Modern smartphones are a dizzying treatise on planned obsolescence. Whether it’s batteries that can’t be removed without four hours and an array of tiny specialized tools, screens that shatter with the lightest shock, or (worst of all) software that gets borked purposefully to make the phone seem older and slower than it really is, around every corner is some excuse to go buy a new device. The truly tragic thing is that there’s often a lot of life left in these old, sometimes slightly broken, devices.
This video shows us how to turn an old smartphone into a perfectly usable laptop. The build starts with a screen and control board that has USB-C inputs, which most phones can use to output video. It’s built into a custom aluminum case with some hinges, and then attached to a battery bank and keyboard in the base of the laptop. From there, a keyboard is installed and then the old phone is fixed to the back of the screen so that the aluminum body doesn’t interfere with the WiFi signal.
If all you need is internet browsing, messaging, and basic word processing, most phones are actually capable enough to do all of this once they are free of their limited mobile UI. The genius of this build is that since the phone isn’t entombed in the laptop body, this build could easily be used to expand the capabilities of a modern, working phone as well. That’s not the only way to get a functioning laptop with parts from the junk drawer, either, if you’d prefer to swap out the phone for something else like a Raspberry Pi.
Pistons being lasered into existence. Image via The Drive
These pistons are printed from high-purity aluminium alloy powder that was developed by German auto parts manufacturer Mahle. Porsche is having these produced by Mahle in partnership with industrial machine maker Trumpf using the laser metal fusion (LMF) process. It’s a lot like selective laser sintering (SLS), but with metal powder instead of plastic.
The machine dusts the print bed with a layer of powder, and then a laser melts the powder according to the CAD file, hardening it into shape. This process repeats one layer at a time, and supports are zapped together wherever necessary. When the print job is finished, the pistons are machined into their shiny final form and thoroughly tested, just like their cast metal cousins have been for decades. Continue reading “Porsche’s Printed Pistons Are Powerful And Precise”→
We take wireless devices for granted these days, and it is easy to forget that the use of the airwaves is subject to government control — the FCC in the United States. HobbyKing got a sharp reminder when the FCC levied a nearly $3 million fine for the company selling uncertified drone transmitters.
It was hardly a surprise, though. The FCC has been cracking down on these noncompliant transmitters for a while now and had issued a notice of apparent liability to the company back in 2018 and the investigation goes back to 2016. The problems included radios being sold that were on unauthorized frequencies, radios with higher than legal output power, and selling radios that were not type accepted.
The jet engine has a long and storied history. Its development occurred spontaneously amongst several unrelated groups in the early 20th Century. Frank Whittle submitted a UK patent on a design in 1930, while Hans von Ohain begun exploring the field in Germany in 1935. Leading on from Ohain’s work, the first flight of a jet-powered aircraft was in August 27, 1939. By the end of World War II, a smattering of military jet aircraft had entered service, and the propeller was on the way out as far as high performance aviation is concerned.
China’s development of ballpoint pen tips was a national news story in 2017. Source: Xinhua
In the age of the Internet and open source, technology moves swiftly around the world. In the consumer space, companies are eager to sell their product to as many customers as possible, shipping their latest wares worldwide lest their competitors do so first. In the case of products more reliant on infrastructure, we see a slower roll out. Hydrogen-powered cars are only available in select regions, while services like media streaming can take time to solve legal issues around rights to exhibit material in different countries. In these cases, we often see a lag of 5-10 years at most, assuming the technology survives to maturity.
In most cases, if there’s a market for a technology, there’ll be someone standing in line to sell it. However, some can prove more tricky than others. The ballpoint pen is one example of a technology that most of us would consider quaint to the point of mediocrity. However, despite producing over 80% of the world’s ballpoint pens, China was unable to produce the entire pen domestically. Chinese manufactured ballpoint tips performed poorly, with scratchy writing as the result. This attracted the notice of government officials, which resulted in a push to improve the indigenous ballpoint technology. In 2017, they succeeded, producing high-quality ballpoint pens for the first time.
The secrets to creating just the right steel, and manipulating it into a smooth rolling ball just right for writing, were complex and manifold. The Japanese, German, and Swiss companies that supplied China with ballpoint tips made a healthy profit from the trade. Sharing the inside knowledge on how it’s done would only seek to destroy their own business. Thus, China had to go it alone, taking 5 years to solve the problem.
There was little drive for pen manufacturers to improve their product; the Chinese consumer was more focused on price than quality. Once the government made it a point of national pride, things shifted. For jet engines, however, it’s somewhat of a different story.
