Author: Bryan Cockfield

1827 Articles

Over-Engineered Single Button Timer

August 28, 2020 by 13 Comments

Feature creep is typically something to be avoided, since watching a relatively simple project balloon into a rat’s nest of complexity often leads to ineffective, or even abandoned, projects. On the other hand, if you can maintain a tight focus, it’s not always a bad thing. [cbm80Amiga] shows us how to drill down and add specific features in this single-button timer without losing focus on what the original project was all about.

The timer is based on an Arduino Pro Mini and an HX1230 LCD with a simple piezo speaker for audible alerts. A single button controls operation of the timer, with short presses incrementing each digit and long presses moving on to the next digit. Controlling button presses this finely is a project in its own, but then [cbm80Amiga] moves on to other features such as backlight control, low power modes which allow it to operate for around two years on a single battery charge, preset times for various kitchen uses, and different appearance settings.

Honestly we aren’t sure how you could cram any more features on this timer without fundamentally altering the designed simplicity. It doesn’t fall into the abyss of feature creep while being packed with features, and it’s another example of how keeping things simple is often a recipe for success.

Thanks to [Hari] for the tip!

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Circle Guitar Creates Wall Of Sound

August 26, 2020 by 24 Comments

In the 60s a musical recording technique called the “wall of sound” came to prominence which allowed artists to create complex layers of music resulting in a novel, rich orchestral feeling. While this technique resulted in some landmark albums (Pet Sounds by the Beach Boys for example) it took entire recording studios and many musicians to produce. This guitar, on the other hand, needs only a single musician but can create impressive walls of sound on its own thanks to some clever engineering.

Called the Circle Guitar and created by [Anthony Dickens], the novel instrument features a constantly-rotating wheel around the guitar’s pickups in the body. Various picks can be attached in different ways to the wheel which pluck the strings from behind continuously. This exceeds what a normal guitar player would be able to do on their own, but the guitarist is able to control the sounds by using several switches and pushbuttons which control a hexaphonic humbucker and are able to mute individual strings at will. Of course, this being the 21st century, it also makes extensive use of MIDI and [Anthony] even mentions the use of a Teensy.

While details on this project are admittedly a little fleeting, the videos linked below are well worth a watch for the interesting sounds this guitar is able to produce. Perhaps paired with a classic-sounding guitar amplifier it could produce other impressive walls of sound as well. Either way, we could expect someone like [Brian Wilson] to be interested in one once it is in production.

Thanks to [Mel] for the tip!

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Schlieren On A Stick

August 25, 2020 by 10 Comments

Schlieren imaging is a technique for viewing the density of transparent fluids using a camera and some clever optical setups. Density of a fluid like air might change based on the composition of the air itself with various gasses, or it may vary as a result of a sound or pressure wave. It might sound like you would need a complicated and/or expensive setup in order to view such things, but with a few common things you can have your own Schlieren setup as [elad] demonstrates.

His setup relies on a cell phone, attached to a selfie stick, with a spherical mirror at the other end. The selfie stick makes adjusting the distance from the camera to the mirror easy, as a specific distance from the camera is required as a function of focal length. For cell phone cameras, it’s best to find this distance through experimentation using a small LED as the point source. Once it’s calibrated and working, a circular field of view is displayed on the phone which allows the viewer to see any change in density in front of the mirror.

The only downside of this build that [elad] notes is that the selfie stick isn’t stiff enough to prevent the image from shaking around a little bit, but all things considered this is an excellent project that shows a neat and useful trick in the photography/instrumentation world that could be useful for a lot of other projects. We’ve only seen Schlieren imaging once before and it used a slightly different method of viewing the changing densities.

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Free Refrigeration In Hot Climates

August 21, 2020 by 34 Comments

Passive homes are a fairly recent trend in home building, but promise a future with minimal energy inputs in our day-to-day. One of the challenges in this year’s Hackaday Prize is to envision ways to add utility to earthen homes often used in refugee camps where there is a housing crisis. Adding passive utilities to these adobe buildings would be a fantastic upgrade, so [Cat] decided to tackle the challenge by creating a refrigerator that needs no electricity.

The the plan for the device works by using evaporative cooling to reduce the temperature in a small box which can be used for food storage. Of course, using evaporative cooling means that you need ready access to water and it likely won’t work in a humid or cool environment, but systems like these have been in use for centuries in plenty of places around the world. [Cat]’s plan is a little more involved than traditional methods of evaporative cooling though, and makes use of a specially painted chimney which provides the airflow when heated by sunlight.

The project is still in its infancy but it would be interesting to see a proof-of-concept built in a real-life passive house in an arid environment. Unfortunately, those of us in humid (or tropical) environments will have to look elsewhere for energy-efficient cooling solutions.

The HackadayPrize2020 is Sponsored by:
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Simple MP3 Player Hides Home Automation Brilliance

August 17, 2020 by 7 Comments

Like bubble wrap or the corkscrew, plenty of everyday objects have lost almost all ties to their original purpose. It could be that the original product had no market but was able to find one in an unexpected place, or simply that the original use case disappeared. We think that this MP3 player for children might arrive at a similar fate as a home automation controller thanks to a recent project by [Sebastian].

The MP3 player is known as a Jooki and works by using small figurines (and a few buttons) to control the device. Different figurines cause the MP3 player to change playlists, for example, but it turns out that the device is capable of communicating over MQTT. This means that [Sebastian] was able to use the MQTT messages from the Jooki to do all kinds of things beyond its intended use with openHAB, an open-source home automation system, such as dimming the lights and closing the blinds when he puts his son to bed.

This platform has considerable potential for hacking thanks to the lightweight communications system it uses under the hood. The Jooki is a little pricey, but if you happen to have one around, it’s an impressive tool that can go well beyond its original intended use.

Anything Becomes A Clock

August 15, 2020 by 5 Comments

Clocks are a popular project around here, and with good reason. There’s a ton of options, and there’s always a new take on ways to tell time. Clocks using lasers, words, or even ball bearings are all atypical ways of displaying time, but like a mathematician looking for a general proof of a long-understood idea this clock from [Julldozer] shows us a way to turn any object into a clock.

His build uses AA-powered clock movements that you would find on any typical wall clock, rather than reaching for his go-to solution of an Arduino and a stepper motor. The motors that drive the hands in these movements are extremely low-torque and low-power which is what allows them to last for so long with such a small power source. He uses two of them, one for hours and one for minutes, to which he attaches a custom-built lazy Suzan. The turntable needs to be extremely low-friction so as to avoid a situation where he has to change batteries every day, so after some 3D printing he has two rotating plates which can hold any object in order to tell him the current time.

While he didn’t design a clock from scratch or reinvent any other wheels, the part of this project that shines is the way he was able to utilize such a low-power motor to turn something so much heavier. This could have uses well outside the realm of timekeeping, and reminds us of this 3D-printed gear set from last year’s Hackaday prize.

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Degrees Of Freedom: Booting ARM Processors

August 12, 2020 by 97 Comments

Any modern computer with an x86 processor, whether it’s Intel or AMD, is a lost cause for software freedom and privacy. We harp on this a lot, but it’s worth repeating that it’s nearly impossible to get free, open-source firmware to run on them thanks to the Intel Management Engine (IME) and the AMD Platform Security Processor (PSP). Without libre firmware there’s no way to trust anything else, even if your operating system is completely open-source.

The IME or PSP have access to memory, storage, and the network stack even if the computer is shut down, and even after the computer boots they run at such a low level that the operating system can’t be aware of what they’re really doing. Luckily, there’s a dark horse in the race in the personal computing world that gives us some hope that one day there will be an x86 competitor that allows their users to have a free firmware that they can trust. ARM processors, which have been steadily increasing their user share for years but are seeing a surge of interest since the recent announcement by Apple, are poised to take over the personal computing world and hopefully allow us some relevant, modern options for those concerned with freedom and privacy. But in the real world of ARM processors the road ahead will decidedly long, windy, and forked.

Even ignoring tedious nitpicks that the distinction between RISC vs CISC is more blurred now than it was “back in the day”, RISC machines like ARM have a natural leg up on the x86 CISC machines built by Intel and AMD. These RISC machines use fewer instructions and perform with much more thermal efficiency than their x86 competitors. They can often be passively cooled, avoiding need to be actively cooled, unlike many AMD/Intel machines that often have noisy or bulky fans. But for me, the most interesting advantage is the ability to run ARM machines without the proprietary firmware present with x86 chips.

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