Remote ADS-B Install Listens In On All The Aircraft Transmissions With RTL-SDR Trio, Phones Home On Cellular

When installing almost any kind of radio gear, the three factors that matter most are the same as in real estate: location, location, location. An unobstructed location at the highest possible elevation gives the antenna the furthest radio horizon as well as the biggest bang for the installation buck. But remote installations create problems, too, particularly with maintenance, which can be a chore.

So when [tsimota] got a chance to relocate one of his Automatic Dependent Surveillance-Broadcast (ADS-B) receivers to a remote site, he made sure the remote gear was as bulletproof as possible. In a detailed write up with a ton of pictures, [tsimota] shows the impressive amount of effort he put into the build.

The system has a Raspberry Pi 3 with solid-state drive running the ADS-B software, a powered USB hub for three separate RTL-SDR dongles for various aircraft monitoring channels, a remote FlightAware dongle to monitor ADS-B, and both internal and external temperature sensors. Everything is snuggled into a weatherproof case that has filtered ventilation fans to keep things cool, and even sports a magnetic reed tamper switch to let him know if the box is opened. An LTE modem pipes the data back to the Inter, a GSM-controlled outlet allows remote reboots, and a UPS keeps the whole thing running if the power blips atop the 15-m building the system now lives on.

Nobody appreciates a quality remote installation as much as we do, and this is a great example of doing it right. Our only quibble would be the use of a breadboard for the sensors, but in a low-vibration location, it should work fine. If you’ve got the itch to build an ADS-B ground station but don’t want to jump in with both feet quite yet, this beginner’s guide from a few years back is a great place to start.

Print Your Own Heat Shrink Labels For Factory-Chic Wire Naming

Heat shrink tubing is great for insulating wires. Labeling wires in a bundle is always useful, too. [Voltlog] has a cheap Brother label printer and discovered he can buy knock off label cassettes for a lot less from China. However, he also found something else: cassettes with heat shrink tubing in them made for the same kind of printer. Could he use the heat shrink cassettes to make neat wire labels? In his first video the answer was sort of, but not really. However, he later had a breakthrough and made a second video explaining how to do it. You can see both videos, below.

At first, the printer didn’t even want to recognize the cassette. It seems like Brother doesn’t want you using exotic tapes with cheap printers. No worry, this isn’t sophisticated DRM, just a sense hole that you need to cover with tape. This discovery was made using the extremely scientific trick of covering all the holes that were not on a regular cassette.

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Simple Bluetooth Car Audio From A Pi Zero

When [Sami Pietikäinen] realized that the Bluetooth built into his car didn’t support audio, he didn’t junk it and buy a Tesla. Instead, he decided to remedy the problem by building a small Bluetooth device that plugged into the Aux socket. To do this, he used a Raspberry Pi Zero with a pHAT DAC (Digital to Audio Converter). That’s perhaps using a sledgehammer to crack a walnut, but sometimes you work with what you have. The interesting part is to be found in what he did next: he used Yocto to optimize the device down to make it as simple and straightforward as possible.

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1940s Portable Radio Is A Suitcase

The meaning of the word portable has changed a bit over the years. These days something has to be pretty tiny to be considered truly portable, but in the 1940s, anything with a handle on it that you could lift with one hand might be counted as portable electronics. Zenith made a line of portable radios that were similar to their famous Transoceanic line but smaller, lighter, and only receiving AM to reduce their size and weight compared to their big brothers. If you want to see what passed for portable in those days, have a look at [Jeff Tranter’s] video (below) of a 6G601 — or maybe it is a GG601 as it says on the video page. But we think it is really a 6G601 which is a proper Zenith model number.

According to [Jeff], 225,350 of these radios were made, and you can see that it closes up like a suitcase. The initial 6 in the model number indicates there are 6 tubes and the G tells you that it can run with AC or batteries.

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Itty Bitty MIDI Piano Sings With Solenoids

Toy pianos are fun to plink around on for a minute, but their small keyboards and even smaller sound make them musically uninteresting pretty quickly. [Måns Jonasson] found a way to jazz up a two-octave toy piano almost beyond recognition. All it took was thirty solenoids, a few Arduinos, a MIDI shield, and a lot of time and patience.

This particular piano’s keys use lever action to strike thin steel tines. These tines are spaced just wide enough for tiny 5V solenoids to fit over them. Once [Måns] got a single solenoid striking away via MIDI input, he began designing 3D printed holders to affix them to the soundboard.

Everything worked with all thirty solenoids in place, but the wiring was a bird’s nest of spaghetti until he upgraded to motor driver shields. Then he designed a new bracket to hold eight solenoids at once, with a channel for each pair of wires. Every eight solenoids, there’s an Arduino and a motor shield.

The resulting junior player piano sounds like someone playing wind chimes like a xylophone, or a tiny Caribbean steel drum. Check out the build video after the break.

Hate the sound of toy pianos, but dig the convenient form factor? Turn one into a synth.

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Mix And Match Parts To Build A Better Mountain Bike Derailleur

Mountain bikers take their sport seriously, and put their bikes through all manner of punishment in the course of a ride. This has given rise to a wide range of specialist equipment, such as suspension, disc brakes and even clutch derailleurs, which help reduce chain slap when riding over rough terrain. However, these specialist derailleurs aren’t available for all applications, so sometimes you’ve gotta hack together your own.

Shimano clutch derailleurs are only really available for 10-speed rear cassettes and up, due to a change in derailleur ratio compared to the earlier 6 to 9 speed cassettes. Using a derailleur designed for 10-speed operation on a rear cassette with fewer gears won’t shift properly.

[SzurkeEg] was inspired by earlier work, and realised that by combining parts from several generations of Shimano hardware, it was possible to build a working clutch derailleur for 6 to 9 speed rear cassettes. The main parallelogram is what handles the positioning of the derailleur, and is sourced from a 9-speed part to get the gear indexes correct.The rest of the parts are sourced from later models with the clutch feature built in.

It’s a smart mechanical hack, and one that isn’t necessarily the most intuitive. But by having a go, and seeing what’s possible, now a whole generation of mountain bikes can tear up the trail like never before. We’ve seen Shimano gear hacked before, too. Video below the break. Continue reading “Mix And Match Parts To Build A Better Mountain Bike Derailleur”

Bolt-On Stepper Motor Driver For The Raspberry Pi

For his entry into the 2019 Hackaday Prize, [Tobius Daichi] is working on adding some motion control capabilities to everyone’s favorite Linux SBC. His 3+Pi board attaches to the Raspberry Pi’s GPIO header and gives you a convenient way to control four individual stepper motors. Perfect for a 3D printer, laser cutter, CNC, or anything else you can think of that needs to move in a few dimensions.

But such a simplistic description of the 3+Pi might be underselling it a bit. While [Tobius] says he was inspired by the classic Arduino CNC Shield that powers countless DIY 3D printers, he’s managed to improve on the concept. Rather than having the host Pi communicate directly with the stepper drivers, the 3+Pi features an onboard STM32F302CBT6 that handles the actual motor control. The Pi just needs to tell it what to do over UART.

If you’re looking to do things in real-time, having an onboard microcontroller handle the low-level aspects of talking to the stepper drivers can be a big help. A natural extension for this board could be support for the Klipper firmware, which leverages the fact that the Raspberry Pi is many times more powerful than your average 3D printer control board. With the Pi handling the math and providing the microcontroller instructions, Klipper allows for faster and more accurate printing than the microcontroller alone could accomplish.

As for the stepper drivers themselves, [Tobius] has decided to go with the Trinamic TMC2041-LA-T. This chip is notable as it puts dual drivers in one 48-QFN package, which is great if you’re looking to save space on your board. Some might complain that the 3+Pi doesn’t allow for easily swapping out the stepper drivers if you manage to cook one like on the Arduino CNC shield, but realistically you could say the same about many purpose-built stepper control boards.

[Tobius] is tackling this project by himself currently, but does mention that he’s open to teaming up with anyone who’s got an interest in this sort of thing. There have been previous attempts at creating Linux-powered 3D printer controllers in the past, but we think this approach holds particular promise if for no other reason than the Raspberry Pi’s popularity.