RADAR Controlled Speakers

[Scott] had a simple problem – he was tired of leaning over his work bench to change the volume on his speakers. He desired a system that would readily allow him to switch the speakers on and off from a more comfortable distance. Not one to settle for the more conventional solutions available, [Scott] whipped up a RADAR-activated switch for his speaker system.

The build relies on a surprisingly cost-effective RADAR module available off the shelf, running in the 5.8GHz spectrum. At under $10, it’s no big deal to throw one of these into a project that requires some basic distance sensing. [Scott] decided to keep things simple – instead of going with a full-fat microcontroller to control the speakers, a 74HC590 IC was used to create a latch. Each time the RADAR module senses an object in close proximity, it toggles the state of the latch. The latch then controls a transistor that switches the power for the speakers.

Overall it’s a build that combines a modern integrated RADAR module with some very simple control logic to create a functional build. Of course, there’s so much more you can do with some 74-series logic. Video after the break.

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5 More SuperCon Speakers You Don’t Want to Miss

This morning it is my pleasure to announce five more confirmed speakers for the Hackaday SuperConference. The ultimate hardware conference takes place in just a few weeks: November 5th and 6th in Pasadena, California.

Get your tickets now!

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Electrostatic Loudspeakers: High End HiFi You Can Build Yourself

If you have an interest in audio there are plenty of opportunities for home construction of hi-fi equipment. You can make yourself an amplifier which will be as good as any available commercially, and plenty of the sources you might plug into it can also come into being on your bench.

There will always be some pieces of hi-fi equipment which while not impossible to make will be very difficult for you to replicate yourself. Either their complexity will render construction too difficult as might be the case with for example a CD player, or as with a moving-coil loudspeaker the quality you could reasonably achieve would struggle match that of the commercial equivalent. It never ceases to astound us what our community of hackers and makers can achieve, but the resources, economies of scale, and engineering expertise available to a large hi-fi manufacturer load the dice in their favour in those cases.

The subject of this article is a piece of extreme high-end esoteric hi-fi that you can replicate yourself, indeed you start on a level playing field with the manufacturers because the engineering challenges involved are the same for them as they are for you. Electrostatic loudspeakers work by the attraction and repulsion of a thin conductive film in an electric field rather than the magnetic attraction and repulsion you’ll find in a moving-coil loudspeaker, and the resulting very low mass driver should be free of undesirable resonances and capable of a significantly lower distortion and flatter frequency response than its magnetic sibling.
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White Oak Illuminated Bluetooth Speaker

Besides being common tools available to most hackers and makers out there, 3D printing, CNC machines, and cheap Chinese electronics have one more things in common: they were all used by [Nick] to build a bluetooth speaker system that has some interesting LED effects built into the case.

This is fresh on the heels of another hack that used similar construction methods to build a “magic” wood lamp. [Nick] takes it a step further, though. His case is precisely machined in white oak and stuffed with the latest China has to offer: a bank of lithium-ion batteries, a DC-DC converter to power the amplifier, and a Bluetooth module. After some sanding, the speakers look professional alongside the blue light features hiding behind the polycarbonate rings.

Of course you’ll want to visit the project site for all the details of how [Nick] built his speaker case. He does admit, however, that the electronics are fairly inefficient and need a little work. All in all though, it’s a very refined set of speakers that’ll look great on a bookshelf or on a beach, workshop bench, or anyplace else that you could take them.

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Upcycle Old Speakers With C.H.I.P.

Sometimes you get a piece of hardware that’s so cool you can’t help but fix it back up. There are a lot of companies after that sweet, sweet Raspberry Pi money, and the $9 US Dollar C.H.I.P. is a very interesting contender for the space. We have been especially enjoying the stream of neat hacks and example projects they’ve been putting out.

In this case, [Peter] wanted to get a pair of walnut speakers up to modern standards. Already suffering from a glut of audio equipment in his personal space, he decided to sweeten the deal by adding support for his library of music.

The first step was ordering a new set of drivers to replace the aged 40-year-old ones occupying the set. After he got them installed, he added C.H.I.P., a power supply, an amplifier, and a 500GB hard-drive. The controlling software behind the installation is the venerable mpd. This way he can control the speakers from any device in his house as long as he had an interface installed for the daemon.

We’re glad these speakers didn’t end up in the garbage behind a goodwill somewhere, and they do look good.

Mid Century Modern Speaker from 90s Road Trash

[BarryAbrams] found some 90s speakers on the side of the road.  At first he thought he might have made a real score, but his coworker who knows about this sort of thing (we all have one) let him know they were merely average. Undaunted, he removed the speakers from their MDF housing, fixed a small dent in one of the tweeters, and got to work.

He cut a new frame for the speakers out of plywood. He adorned the plywood box with maple and walnut from a local supplier. The box then got a coat of urethane. His skill at sign making showed in the final finish, and the wood looks very good. Our only complaint is the straight legs instead of the slightly angled and tapered ones common to mid-century modern furniture style.

The electronics are a Chinese amp and a Sonos knock-off. [Barry] only needed to control the volume and power for the speaker set. He came up with a clever 3D-printed knob and switch configuration. When the volume is turned all the way down the speaker set turns off.

The end result sounds and looks better than anything he could get for the $125 US Dollars he spent on the project. We certainly wouldn’t complain if this were a fixture in our living space.

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Hacklet 91: Ultrasonic Projects

Ultrasound refers to any audio signal above the range of human hearing. Generally that’s accepted as 20 kHz and up. Unlike electromagnetic signals, ultrasonics are still operating in a medium – generally the air around us. Plenty of animals take advantage of ultrasonics every day. So do hackers, makers, and engineers who have built thousands of projects based upon these high frequency signals. This weeks Hacklet is all about the best ultrasonic projects on Hackaday.io!

spambakeWe start with [spambake] and World’s Smallest Bat Detector. [Spambake] is interested in bats. These amazing creatures have poor eyesight, but that doesn’t slow them down. Bats use echolocation to determine their surroundings. Ultrasonic chirps bounce off obstacles. The bat listens to the echos and changes its flight path accordingly. While we can’t hear most of the sounds bats make, electronics can. [Spambake] cooked this circuit up starting with a MEMs microphone. These microphones pick up human sounds, but unlike our ears, they can hear plenty above the 20 kHz range. The audio signal is passed through an amplifier which boosts the it up around 10,000 times. The signal is filtered and then used to trigger LEDs that indicate a bat is present. The final circuit works quite well! Check out [spambake’s] video to see the bat detector in action!

movvaNext up is [Neil Movva] with Pathfinder – Haptic Navigation. Pathfinder uses ultrasonic transducers to perform echolocation similar to bats. The received data is then passed on to a human wearer. [Neil’s] idea is to use Pathfinder to help the visually disabled and blind navigate the world around them. Pathfinder was a 2015 Hackaday Prize finalist. The ultrasonic portion of Pathfinder uses the ubiquitous HC-SR04 distance sensor, which can be found for as little as $2 USD on eBay and Alibaba. These sensors send out a 60 kHz signal and listen for the echos. A microcontroller can then measure the time delay and determine the distance from the sensor to an obstacle. Finally the data is passed on to the user by a vibrating pager motor. [Neal] was kind enough to give a talk about Pathfinder at the 2015 Hackaday SuperCon.

levitate[HoboMunching] likes his ultrasonic devices ultra powerful, and that’s just what he’s got with Ultrasonic Levitation Rig. Inspired by a similar project from Mike, [HoboMunching] had to build his own levitation setup. Ultrasonic levitation used to be a phenomenon studied only in the laboratory. Cheap transducers designed for the industrial world have made this experiment practical for the home hackers. [HoboMunching] was able to use his rig to levitate up to 8 tiny balls on the nulls between the 28.5 kHz sound waves produced by his transducer. The speed of sound can be verified by measuring the distance between the balls. Purists will be happy to hear that [HoboMunching]’s circuit was all based upon the classic 555 timer.

speaker-arrayFinally we have [Alan Green] with Ultrasonic Directional Speaker V1. Most audio signals are not very directional, due to wavelength and practical limitations on speaker size. Ultrasonics don’t have this limitation. Couple this with the fact that ultrasonic signals can be made to demodulate in air, and you have the basis for a highly directional speaker setup. “Sound lasers” based on this system have been around for years, used in everything from targeted advertising to defensive weapons. [Alan] is just getting started on this project. Much of his research is based upon [Joe Pompei’s] work at the MIT media lab. [Alan] plans to use an array of ultrasonic transducers to produce a directional signal which will then demodulate and be heard by a human. This project has a hard deadline though:  [Alan] plans to help his son [Mitchell] with a musical performance that is scheduled for May, 2016. The pair hope to have a prototype in place by March.

If you want to see more ultrasonic projects, check out our new ultrasonic projects list! If I missed your project, don’t be shy! Just drop me a message on Hackaday.io. That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!