Lofipi Keeps The Chill Beats Coming

April 25, 2022 by Lewin Day 21 Comments

These days, many people love having some lo-fi beats on when they chill and study. This has led to a cottage industry dedicated to producing said beats, and the format continues to grow in popularity. [Nicholas Sherlock] decided to build a custom audio device solely for the delivery of these comfortable tunes.

As seen on Reddit, the build relies on a Raspberry Pi 3B, paired with an X400 audio amplifier board and hooked up to a nicely-sized mid-range speaker. The hardware is assembled inside a case printed out of wood-effect PLA filament, giving it a nice old-school home audio aesthetic. As a bonus, the layer lines line up in such a way as to boost the woodgrain effect. Plug it in, and you will be immediately rewarded with lo-fi beats from boot.

Originally, the system ran a port of the code from lofigenerator.com, which algorithmically creates lo-fi beats from scratch. However, [Nicholas] could not in good conscience share the ported code, and has retooled the system to stream YouTube playlists using command line media player mpv instead. It’s set to stream typical lo-fi playlists, though could be repurposed to target anything on the platform.

It’s a nice build that really suits the lo-fi beats ideal. When you’re trying to study or focus, you don’t want to be mucking around with a YouTube tab open serving as a distraction. Instead, you can simply flick on the Lofipi, and vibe out.

The Raspberry Pi’s cheap price and great internet and media capabilities make it very popular for builds like these. They go some way to recreating the idea of receiving a broadcast, rather than forcing us into choice as per today’s modern on-demand media paradigm. If you’ve got thoughts on this, drop them in the comments, and if you’ve got your own great projects, do drop us a line.

Learning Electronics By Just Doing It

April 25, 2022 by Ryan Flowers 33 Comments

Learning anything new, especially so broad and far reaching as electronics, can be hard. [IMSAI Guy] knows this because he gets asked regularly “how do I learn electronics?” Many of you reading this will have a few ideas to pass along (and we encourage you to share your take on it in the comments below) but there is an even greater number of people who are asking the same question, and [IMSAI Guy]’s take on it is one that this particular Hackaday writer can relate to.

The ARRL Handbook can be found at hamfests, radio clubs, libraries, or at arrl.org

According to [IMSAI Guy], an excellent place to start is the ARRL Handbook. The ARRL Handbook is an electronics and RF engineering guide published by the Amateur Radio Relay League in the US. It’s a wonderful reference, and past editions can be had very inexpensively and are every bit as handy. Many hams will have a copy they could be talked out of, and you can likely find one at your local library. Where to start in the Handbook, then?

[IMSAI Guy] recommend starting with whatever catches your fancy. As an example, he starts with Op Amps, and rather than diving straight into the math of how they work or even worrying to much about what they are- he just builds a circuit and then plays with it to intrinsically understand how it works, a “learn by doing” approach that he has found extremely helpful just as many of us have. We also appreciated is very straightforward approach to the math: Don’t bother with it unless you need to for some reason, and definitely don’t start by learning it first.

In fact, that same reasoning is applied to any subject: Learn it as you need it, and don’t start by learning but rather by doing. The learning will come on its own! Be sure to check out the entire video and let us know what you think, and how you approached learning electronics. Thanks to [cliff] for the great Tip!

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The Apollo Digital Ranging System: More Than Meets The Eye

April 25, 2022 by Ryan Flowers 15 Comments

If you haven’t seen [Ken Shirriff]’s teardowns and reverse engineering expeditions, then you’re in for a treat. His explanation and demonstration of the Apollo digital ranging system is a fascinating read, even if vintage computing and engineering aren’t part of your normal fare.

The average Hackaday reader should be familiar with the concept of determining the distance of a faraway object by measuring how long it takes a sound or radio wave to be reflected, such as in sonar and radar. Going another step and measuring Doppler Shift – the difference in the returned signal’s frequency – will tell us the velocity of the object relative to our position. It’s so simple that an Arduino can do it. But in the days of Apollo, there was no Arduino. In fact, there were no Integrated Circuits. And Apollo missions went all the way to the moon- far too distant for relatively simple Radar measurements. Continue reading “The Apollo Digital Ranging System: More Than Meets The Eye” →

3D Printed Turbo Pump Hopes To Propel Rockets To The Sky

April 25, 2022 by Lewin Day 22 Comments

There are plenty of rocket experimenters toying with various liquid-fueled contraptions at the moment, and [Sciencish] is one of them. He grew tired of using air-pressurized fuel delivery systems in his experiments due to safety reasons, and decided to create something approximating more grown up rocket designs. The result was a 3D-printed turbopump for fuel delivery.

The design is not dissimilar from a turbocharger in a car. On one side, a turbine wheel is turned by compressed air supplied from a tank or compressor. This turbine wheel is affixed to the same axle as an impeller which draws up fuel and pumps it out, ideally into a rocket’s combustion chamber. It’s all made out of resin-printed parts, which made creating the fine geometry of the turbine and impeller a cinch.

Running on compressed air at 80 psi, the turbopump is able to deliver 1.36L of water or rubbing alcohol fuel a minute. However, unfortunately, this first pass design can only deliver 20 psi of fuel pressure, which [Sciencish] suspects will not be enough to counteract combustion chamber pressures in his rocket design. More work is required to up this figure. Paired with a nozzle and ignition source, though, and it does make for some great flames.

Overall though, the safety benefit of this turbopump comes from the fact that the fuel is kept separate from the oxidizer until it reaches the combustion chamber. This comes with far less chance of fire or explosion versus a system that stores fuel pressurized by air.

While the design isn’t yet up to scratch for rocket use, it nonetheless works, and we suspect with some improvement to tolerances and fin design that the project should move along at a quick pace.

If solid rockets are more your thing though, we’ve featured plenty of those too. Video after the break.

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2022 Sci-Fi Contest: A Mac-Based Droid Named R.O.B.

April 25, 2022 by Lewin Day 12 Comments

Droids and robot assistants are still not really a part of our daily lives, even if they started showing up in movies many long decades ago. [Rudy Aramaryo] perhaps hopes that will change one day, and is pursuing this goal with their own droid build named R.O.B.

R.O.B. is quite a hefty ‘bot, weighing 140 lbs and sporting a full 80 Ah of lithium-iron-phosphate batteries for a long running time and plenty of power. For brains, R.O.B. packs in an Apple Mac Mini M1 and a Mac Studio, running OS X. It’s an unusual choice for a robot, but one that brings plenty of computing power to bear, nonetheless. Equipped with tracked propulsion, R.O.B. also features a slip-ring setup in the base allowing the droid to rotate endlessly without tangling wires.

By virtue of its size and power, R.O.B. goes a long way to emulating the general feel of the droids of the Star Wars series. It’s all about the roughly-human-scaled design, and the anthropomorphic features. Further helping the cause are a basic chat ability powered by Python, along with arms and actuators to interact with the world.

The name of this droid recalls us of the charming Nintendo console toy from the 1980s. If these aren’t the droids you’re looking for, and you’ve been hacking on ‘bots of your own, be sure to drop us a line.

Explosion Welding Goes Off With A Bang

April 25, 2022 by Lewin Day 25 Comments

Welding is often a hot and noisy process. It generally involves some fancy chemistry and proper knowledge to achieve good results. Whether you’re talking about arc, TIG, or MIG, these statements all apply.

The same is true for explosion welding, though it’s entirely unlike any traditional hand welding methods you’ve ever seen before. Today, we’ll explore how this technique works and the applications it’s useful for. Fire in the hole!

Don’t Blow Them Apart, Blow Them Together!

Explosion welding occurs near-instantaneously, but is done in a progressive fashion. The angle of collision, as well as the speed of the explosive front, is key to getting a quality weld. Image credit: NASA, public domain

The technique of explosion welding is relatively new compared to other metal-joining techniques. In the two World Wars of the 20th century, pieces of shrapnel were often found stuck to armor plating. Close observation showed that shrapnel was in fact welding on to metal armor, rather than simply being embedded in such. Given that collisions between shrapnel and armor often occur without the extreme heat of typical welding operations, it indicated that it was instead great velocity of the impact between shrapnel and armor that was melding the metals together.

The same results were later recreated in the lab, and explosoin welding was developed into a refined technique after World War II. 1962 saw DuPont patent a process for explosion welding later to be known under the “Detaclad” trademark.

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Software Defined Instrumentation Hack Chat

April 25, 2022 by Dan Maloney 14 Comments

Join us on Wednesday, April 27 at noon Pacific for the Software Defined Instrumentation Hack Chat with Ben Nizette!

Imagine, if you will, the perfect electronics lab. Exactly how it looks in your mind will depend a lot upon personal preferences and brand loyalty, but chances are good it’ll be stocked to the gills with at least one every conceivable type of high-precision, laboratory-grade instrument you can think of. It’ll have oscilloscopes with ridiculously high bandwidths, multimeters with digits galore, logic analyzers, waveform generators, programmable power supplies, spectrum analyzers — pretty much anything and everything that can make chasing down problems and developing new circuits easier.

Alas, the dream of a lab like this crashes hard into realities like being able to afford so many instruments and actually finding a place to put them all. And so while we may covet the wall of instruments that people like Marco Reps or Kerry Wong enjoy, most of us settle for a small but targeted suite of instruments, tailored to our particular needs and budgets.

It doesn’t necessarily need to be that way, though, and with software-defined instrumentation, you can pack a lab full of virtual instruments into a single small box. Software-defined instrumentation has the potential to make an engineering lab portable enough for field-service teams, flexible enough for tactical engineering projects, and affordable for students and hobbyists alike.

Ben Nizette is Product Manager at Liquid Instruments, the leader in precision software-defined instrumentation. He’s the engineer behind Moku:Go, the company’s first consumer product, which squeezes eleven instruments into one slim, easily transported, affordable package. He’s been in the thick of software-defined instrumentation, and he’ll drop by the Hack Chat to talk about the pros and cons of the virtual engineering lab, what it means for engineering education, and how we as hobbyists can put it to work on our benches.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, April 27 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

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