3D Printed Marble Music Machine Looking Good Already

November 16, 2021 by 6 Comments

Inspired by the enormous marble music machines from the staggeringly talented [Wintergatan] and the marble run builds by [Daniel de Bruin], [Ivan Miranda] has been busy again building a largely 3D printed contraption to test his ideas around building his own marble music machine from scratch. (Video, embedded below.)

Leveraging his recent experiences with resin printing and his own giant 3D printer, he had no difficulty in producing everything he needed from his workshop, even if the design work apparently took ages.

The build shows how early in development this project is, as there are clearly quite a few issues to be dealt with, but progress looks encouraging so far. To be clear, plans are to ‘go big’ and this little eight-channel testbed is just to explore this issues around ball guiding, transport and ball release onto the first audio test device, a Korg Nano Pad 2.

Some significant teething problems were identified, such as when [Ivan] designed the ball lifter, he intended the balls to load from the rear, but then needed to switch it to load from the front. No big deal, simply reverse the motor direction to load balls on the opposite side of the mechanism. Sadly, that also meant the directly coupled note drum was now also rotating the wrong way to release the balls. Oops. A quick hack later and [Ivan] was back in business. Various parts needed shimming up with plates, but with 3D printers on the bench, knocking those out took little time or effort. This just shows how darn useful 3D printers can be, allowing you to iterate in a short time and feed your hacks back into the final version.

[Ivan] is clearly going to have a lot of ‘fun’ with this one, as [Wintergatan] will surely testify, these big musical marble machine builds are quite some undertaking. We shall definitely be tuning in later on to see where this one goes!

While we’re on the subject of the [Wintergatan] marble machines, here’s a mini homage to the latest Marble Machine X, and if you’re in the need for a 3D printed marble clock, then try this one for starters.

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Tech In Plain Sight: Eyeglasses

November 16, 2021 by 47 Comments

Glasses wearers, try a little experiment. Take off your glasses and look at this page or, at least, at something you can’t see well without your glasses. Now imagine if you lived in a time where there was nothing to be done about your vision. If you wear contacts or you have good vision — perhaps you had surgery — then congratulations. But for most of us, vision changes with age are a fact of life. Even many young people need glasses or some other intervention to get good eyesight. At first glance, you might think eyeglasses are an obvious invention, but it turns out we didn’t get real glasses for quite some time and modern glasses are truly a piece of high tech that hides — quite literally — right in front of your face.

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For All Their Expense, Electric Cars Are Still The Cheapest

November 16, 2021 by 191 Comments

A criticism that we have leveled at the move from internal combustion vehicles to electric ones is that their expense can put them well beyond the range of the not-so-well-heeled motorist. Many of the electric vehicles we’ve seen thus far have been niche models marketed as luxury accessories, and thus come with a specification and list price to match. It’s interesting then to see a European report from LeasePlan looking at vehicle ownership costs which reveals that the total yearly cost of ownership (TCO) for an electric car has is now cheaper that comparable internal combustion vehicles across the whole continent in all but the fiercely competitive sub-compact segment.

TCO includes depreciation, taxes and insurance, fuel, and maintenance. Perhaps the most interesting story lies in electric cars progressing from being a high-depreciation, risky purchase to something you can sell on the second-hand market, even if they cost more up front. For example, the electric VW ID3 costs around $11,000 more than the comparable gas-powered VW Golf up front, but the higher resale price later offsets this and helps keep the TCO lower.

We’ve been following electric vehicles for a while now in the hope that an electric people’s car would surface, and have at times vented our frustration on the matter. It’s encouraging to see this particular trend as we believe it will encourage manufacturers to produce more accessible electric vehicles, especially given that we’ve just complained that driving electric seems like more of a rich man’s game.

(via Heise)

Header image: CEphoto, Uwe Aranas / CC-BY-SA-3.0.

Making Your Own Touchpad With PWM And Rust

November 16, 2021 by 9 Comments

The modern touchpads are incredible feats of engineering, with everything from complex signal processing for noise and tremendous economies of scale driving prices low. So [Kevin] decided to see if he could make his own touchpad. Partially out of curiosity of what makes one touchpad better than another, but also because he was curious if he could. Using an STM32 and a custom PCB, he was off to the races in an incredibly cost-effective way.

After writing some quick firmware in Rust, he was reporting the values read by the PWM channels. Using python, he could get a good idea of the raw values that were being written over USB and visualized. So rather than implement filtering in hardware or firmware, he elected to do the filtering and processing on the host computer side in Python. We suspect this gave him much shorter iteration cycles.

If you like the idea of making your own touchpad but perhaps are dreaming a little bigger, why not make a tablecloth-sized touchpad?

Pluto Spectrum Analyzer Uses Command Line

November 15, 2021 by 11 Comments

If you don’t care about shortwave frequencies, the PlutoSDR is a great deal. The device is supposed to be an evaluation board for Analog Device’s radio chips, but it does great as a software-defined radio that can receive and transmit and it even runs Linux internally. [SignalsEverywhere] shows how to use it as a spectrum analyzer that works from the command line in the video you can see below.

The software used is Retrogram. Despite the ASCII graphics, the program has many features. You can use simple keystrokes to change the center frequency, the sampling rate, the bandwidth, and more. You can run the software on a Linux host or compile a binary on the box or cross-compile using tools on the Raspberry Pi.

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Machine Learning Shushes Stressed Dogs

November 15, 2021 by 20 Comments

If there’s one demographic that has benefited from people being stuck at home during Covid lockdowns, it would be dogs. Having their humans around 24/7 meant more belly rubs, more table scraps, and more attention. Of course, for many dogs, especially those who found their homes during quarantine, this has led to attachment issues as their human counterparts have begin to return to work and school.

[Clairette] has had a particularly difficult time adapting to her friends leaving every day, but thankfully her human [Nathaniel Felleke] was able to come up with a clever solution. He trained a TinyML neural net to detect when she barked and used and Arduino to play a sound byte to sooth her. The sound bytes in question are recordings of [Nathaniel]’s mom either praising or scolding [Clairette], and as you can see from the video below, they seem to work quite well. To train the network, [Nathaniel] worked with several datasets to avoid overfitting, including one he created himself using actual recordings of barks and ambient sounds within his own house. He used Eon Tuner, a tool by Edge Impulse, to help find the best model to use and perform the training. He uploaded the trained network to an Arduino Nano 33 BLE Sense running Mbed OS, and a second Arduino handled playing sound bytes via an Adafruit Music Maker Featherwing.

While machine learning may sound like a bit of an extreme solution to curb your dog’s barking, it’s certainly innovative, and even appears to have been successful. Paired with this web-connected treat dispenser, you could keep a dog entertained for hours.

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Designing Electronics That Work

November 15, 2021 by 36 Comments

[Hunter Scott] who has graced these pages a fair few times, has been working on electronics startups for the past ten years or so, and has picked up a fair bit of experience with designing and building hardware. Those of us in this business seem to learn the same lessons, quite often the hard way; we call it experience. Wouldn’t it be nice to get up that learning curve a little quicker, get our hardware out there working sooner with less pain, due to not falling into the same old traps those before us already know about? The problem with the less experienced engineer is not their lack of talent, how quickly they can learn, nor how much work they can get done in a day, but simply that they don’t know what they don’t know. There’s no shame in that, it’s just a fact of life. [Hunter] presents for us, the Guide to Designing Electronics that Work.

The book starts at the beginning. The beginning of the engineering process that is; requirements capturing, specifications, test planning and schedule prediction. This part is hard to do right, and this is where the real experience shows. The next section moves onto component selection and prototyping advice, with some great practical advice to sidestep some annoying production issues. Next there’s the obvious section on schematic and layout with plenty of handy tips to help you to that all important final layout. Do not underestimate how hard this latter part is, there is plenty of difficulty in getting a good performing, minimal sized layout, especially if RF applications are involved.

The last few sections cover costing, fabrication and testing. These are difficult topics to learn, if up till now all you’ve done is build prototypes and one-offs. These are the areas where many a kickstarter engineer has fallen flat.

Designing Electronics That Work doesn’t profess to be totally complete, nor have the answer to everything, but as the basis for deeper learning and getting the young engineer on their way to a manufacturable product, it is a very good starting point in our opinion.

The book has been around a little while, and the latest version is available for download right now, on a pay what-you-want basis, so give it a read and you might learn a thing or two, we’re pretty confident it won’t be time wasted!