Fail Of The Week: How Not To Make A 3D Scanner

July 23, 2018 by 12 Comments

Sometimes the best you can say about a project is, “Nice start.” That’s the case for this as-yet awful DIY 3D scanner, which can serve both as a launching point for further development and a lesson in what not to do.

Don’t get us wrong, we have plenty of respect for [bitluni] and for the fact that he posts his failures as well as his successes, like composite video and AM radio signals from an ESP32. He used an ESP8266 in this project, which actually uses two different sensors: an ultrasonic transducer, and a small time-of-flight laser chip. Each was mounted to a two-axis scanner built from hobby servos and 3D-printed parts. The pitch and yaw axes move the sensors through a hemisphere gathering data, but unfortunately, the Wemos D1 Mini lacks the RAM to render the complete point cloud from the raw points. That’s farmed out to a WebGL page. Initial results with the ultrasonic sensor were not great, and the TOF sensor left everything to be desired too. But [bitluni] stuck with it, and got a few results that at least make it look like he’s heading in the right direction.

We expect he’ll get this sorted out and come back with some better results, but in the meantime, we applaud his willingness to post this so that we can all benefit from his pain. He might want to check out the results from this polished and pricey LIDAR scanner for inspiration.

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Be A Fire Bender With The Power Of Magnets

July 23, 2018 by 26 Comments

More often than you think, scientific progress starts with a simple statement: “Huh, that’s funny…” That’s the sign that someone has noticed something peculiar, and that’s the raw fuel of science because it often takes the scientist down interesting rabbit holes that sometimes lead to insights into the way the world works.

[Ben Krasnow] ended up falling down one of those rabbit holes recently with his experiments with magnets and flames. It started with his look at the Zeeman effect, which is the observation that magnetic fields can influence the spectral lines of light emitted by certain sources. In a previous video, [Ben] showed that light from a sodium lamp could be dimmed by a powerful electromagnet. Some of his viewers took exception to his setup, which used an oxy-acetylene flame doped with sodium passing through the poles of the magnet; they thought the effect observed was a simple magnetohydrodynamic effect, and not the Zeeman effect he was supposed to be testing. That led to the experiments in the video below, which started with a candle flame being strongly deflected by the magnet. [Ben] methodically worked through the problem, eliminating variables by going so far as to blow soap bubbles of various gasses within the magnet’s poles to rule out the diamagnetism of oxygen as a cause of the phenomenon. He finally showed that even hot air by itself is deflected, using a simple light bulb and a FLIR camera. It’s good stuff, and well worth a watch.

Spoiler alert: [Ben] is still scratching his head about what’s going on, and we’re looking forward to his conclusions. This isn’t his first rabbit hole expedition, of course; his experiments with creating plasma with high-pressure water were fascinating, as were his DIY superconducting ceramics. Continue reading “Be A Fire Bender With The Power Of Magnets” →

Build A Wi-Fi Smart Scale

July 23, 2018 by 10 Comments

There are plenty of ways to monitor changes in your weight. You can get a vague idea from the fit of your pants or the notch on your belt. But anyone who’s serious about getting or staying in shape must step on the scale to get the cold, hard truth in pounds or kilograms.

Instead of just buying one, [igorfonseca83] decided to burn a few calories and build his own smart scale that uses IFTTT to send weight data to his fitness tracker. It’s made from four 50kg load cells that are sandwiched between two pieces of plywood. An HX711 sensor module reads the load cells, and a FireBeetle ESP8266 uploads the data to Adafruit IO. His weight is simultaneously displayed on a FireBeetle LED matrix.

We applaud [igorfonseca83]’s efforts to make this an easy, educational project that anyone can replicate. The instructions are great, the pictures are clear, and there’s even a CAD animation of all the pieces coming together. Jog past the break to see the build video, and weigh in down below.

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HOPE XII: Time Travel With Software Defined Radio

July 23, 2018 by 51 Comments

It’s easy to dismiss radio as little more than background noise while we drive.  At worst you might even think it’s just another method for advertisers to peddle their wares. But in reality it’s a snapshot of the culture of a particular time and place; a record of what was in the news, what music was popular, what the weather was like, basically what life was like. If it was important enough to be worth the expense and complexity of broadcasting it on the radio, it’s probably worth keeping for future reference.

But radio is fleeting, a 24/7 stream of content that’s never exactly the same twice. Yet while we obsessively document music and video, nobody’s bothering to record radio. You can easily hop online and watch a TV show that originally aired 50 years ago, but good luck finding a recording of what your local radio station was broadcasting last week. All that information, that rich tapestry of life, is gone and there’s nothing we can do about it.

Or can we? At HOPE XII, Thomas Witherspoon gave a talk called “Creating a Radio Time Machine: Software-Defined Radios and Time-Shifted Recordings”, an overview of the work he’s been doing recording and cataloging the broadcast radio spectrum. He demonstrated how anyone can use low cost SDR hardware to record, and later play back, whole chunks of the AM and shortwave bands. Rather than an audio file containing a single radio station, the method he describes allows you to interactively tune in to different stations and explore the airwaves as if it were live.

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Turn A Cheap Bluetooth Speaker Into An Audio Receiver

July 23, 2018 by 16 Comments

Cheap Bluetooth speakers come in all different kinds of shapes and colors, and they let you conveniently stream music, for example from your mobile phone. For [mcmchris], they had one significant shortcoming though: while most of them come with some auxiliary input port as alternative audio source, they usually lack an audio output port that would let him route the audio to his more enjoyable big-speaker sound setup. Lucky for him, it’s a problem that can be fixed with a wire cutter and soldering iron, and so he simply turned his cheap speaker into a Bluetooth audio receiver.

After opening the speaker, [mcmchris] discovered a regular F-6188 Bluetooth audio module built around the BK8000L chip, with the audio jack connected to the chip’s aux input pins. Taking a close look at the PCB, the solution seemed obvious: cut the connection to the chip’s aux input pins, and connect the audio jack parallel to the audio signal itself. After some trial and error, the output pins of the on-board op amplifier seemed to provide the best audio signal for his shiny new output jack. You can see more details about the speaker’s inner life and a demonstration in the video after the break — in Spanish.

If the concept looks familiar to you, we’ve indeed seen a very similar approach to equip a Google Home Mini with an audio output jack before. The alternative is of course to just build a decent sized Bluetooth speaker yourself.

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Hands On With Python 3.7: What’s New In The Latest Release

July 23, 2018 by 42 Comments

Used for general purpose programming, data science, website backends, GUIs, and pretty much everything else; the first programming language for many, and claimed to be the fastest growing in the world, is of course Python. The newest version 3.7.0 has just recently been released.
Naturally any release of Python, no matter how small, undergoes meticulous planning and design before any development is started at all. In fact, you can read the PEP (Python Enhancement Proposal) for Python 3.7, which was created back in 2016.

What’s new in 3.7? Why should you upgrade? Is there anything new that’s actually useful? I’ll answer these questions for you by walking through some examples of the new features. Whilst there’s not much in this release that will make a difference to the Python beginner, there’s plenty of small changes for seasoned coders and a few headline features you’ll want to know about.

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Fail Of The Week: ESP Walkie, Not-So-Talkie

July 23, 2018 by 51 Comments

The ESP8266 has become such a staple of projects in our community since it burst onto the scene a few years ago. The combination of a super-fast processor and wireless networking all on the same chip and sold in retail quantities for relative pennies has been irresistible. So when [Petteri Aimonen] needed to make a wireless intercom system for cycling trips it seemed an obvious choice. Push its internal ADC to sample at a high enogh rate for audio, and stream the result over an ad-hoc wi-fi network.

The result was far from satisfactory, as while early results with a signal generator seemed good, in practice it was unusable. Significant amounts of noise were entering the pathway such that the resulting audio was unintelligible. It seems that running a wireless network causes abrupt and very short spikes of power supply current that play havoc with audio ADCs.

He’s submitted it to us as a Fail Of The Week and he’s right, it is a fail. But in a way that’s an unfair description, because we can see there is the germ of a seriously good idea in there. Perhaps with an external ADC, or maybe with some as-yet-to-be-determined filtering scheme, an ESP8266 walkie-talkie is one of those ideas that should be taken to its conclusion. We hope he perseveres.