Raspberry Pi Remote Audio Link

Hardware for remote audio link

 

In broadcast, lots of people are still using dedicated analog lines to connect remote sites. These operate like old telephone systems: you call up the operator and request to be patched through to a specific site. They’re also rather expensive.

For a hospital radio station, [Marc] wanted to replace the old system with something less costly. The result is his Raspberry Pi STL in a Box. Inside the box is a Raspberry Pi, PiFace display, a pair of meters, and some analog hardware for the audio.

On the software side, the system uses LiquidSoap to manage the stream. LiquidSoap uses a language to configure streams, and [Marc] has a write-up on how to configure LiquidSoap for this application. On the hardware side, SSM2142 ICs convert the signal from single-ended to balanced. The meters use the LM3915 bar drivers to control the meters.

The Python script that controls the box is provided, and could be helpful for anyone needing to build their own low-cost audio link.

 

DIY Bluetooth Boombox Can Take a Beating!

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Looking for a nice portable audio solution that can take a beating outdoors? This RaveBOX (v1.0) might be what you’re looking for!

[Angelo] is a 15 year old high school student from the Philippines who loves making things — in fact, he has a collection over 40 Instructables that he’s written himself to share with the world. He wrote his first when he was only 10 years old.

He was inspired to build this boombox when he stumbled upon a Pelican-like rugged case at the mall, so he bought it and started planning the build around it. He’s using a pair of 2-channel audio amplifiers hooked up to a Bluetooth/FM/USB/SD card player module which has a nice face-plate for external mounting. It drives a 4″ woofer, and 4 full range speakers. To modify the case, he used a Dremel and pocket knife, and we must say, he did a great job! The 12V 2.2aH lithium polymer battery provides a surprising 18 hours of playback. [Read more...]

From Wireless Soundbar to Portable Boombox

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[Frank] had wanted a portable Bluetooth boombox for a while, but when he did some price comparisons he found that they are pretty expensive. He decided to take matters into his own hands and modify two products he already had — into what he wanted.

The guts of his Frankenstein-boombox come from a Toshiba 3D Soundbar — a great product, but not as durable or portable as he needed. He then took an old mini guitar amp and started hacking the two together.

The soundbar features 4 speakers and a sub woofer — plus the amp and wireless capabilities of course — so [Frank] opted to just use the case of the guitar amp with the soundbar’s innards. He took some measurements and then built up a wooden support for the speakers inside the amp. He’s also sealed off the tweeters sound cavity from the main SUB to keep the sound nice and clear.  [Read more...]

SoundCube: A Companion Cube that can Talk

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The Enrichment Center likely disapproves of the SoundCube: a portal music box in the form of a Portal Companion Cube. [Andreas] finished this project a couple of years ago, but we’re glad he’s finally had time to give a rundown on the details at his blog.

The build is primarily a modified speaker box cube—constructed out of what appears to be MDF—with four Alpine SXE-1725S speakers placed at the center of the middle faces. The faces were routed out to resembled the Companion Cube, while the electronics mount and the speaker grills were 3d printed. Inside is a homemade amplifier built around an Arduino Mega, with a TDA7560 quad bridge amplifier, a TDA7318 audio processor, a Belkin bluetooth receiver, and a 3.5″ touchscreen for volume control and for input selections.

Two 12v 7.2Ah lead-acid batteries keep the cube functional for an entire weekend of partying, but probably add a few pounds to the already hefty MDF construction. Check out [Andreas's] blog for more pictures and his GitHub for all the necessary code.

Vintage DACs And A Raspberry Pi

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Before the days of iPod docks in every conceivable piece of audio equipment, most devices were actually built very well. Most shelf top equipment usually came with well designed circuits using quality components, and late 90s CD players were no exception. [Mariosis] heard of some very nice DACs found in some of these units and decided to take one out for a spin. He’s using a Raspberry Pi to play audio with the DAC found in a late 90s Kenwood CD player.

After fortune favored a CD player with a dead drive on [Mariosis]‘ workbench, he dug up the service manual and found some interesting chips – a PCM56 DAC, a little bit of logic, and an SM5807 oversampling chip that does all the conversion for the DAC.

This oversampling chip uses an I2S – not I2C – bus to carry the data from the CD to the DAC. There is, of course, an I2S driver for the Raspi, but the first attempts at playing audio didn’t result in anything. It turned out there was a problem with what the oversampler expected – the ‘standard’ I2S signal delays the data one tick behind the LRCLK signal.

There are two ways to fix this problem: programming a kernel driver, or building some custom logic to fix the problem. Obviously breaking out some flip-flops and NOR gates was the cooler option, giving [Mariosis] a great sounding stereo with a vintage DAC.

Under Water Record Player is Very Mesmerizing

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Once in a while we get a really awesome tip about a technical art installation — there sometimes isn’t much info behind it, but the idea and concept behind it alone sparks our curiosity. That is most definitely the case for this submerged record player.

Artist [Evan Holm] has created this awesome installation which features a black pool of water — with a built-in record player. He’s somehow waterproofed the player itself, and integrated the controls and needle into a tree, which is part of the installation.

He has a very long and artsy description about the meaning of it, how it represents loss and mystery, and the collective subconscious of the human race… We just see it as a really cool hack. There’s also a full documentary about how he sets up the installation at various shows.

We’ve included both videos following the break — it is very tempting to try recreating something similar!

[Read more...]

Hanging Glass Speakers Look Super Cool

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Looking for a modern way to spice up your apartment? Well if you’re not too much of an audiophile, these hanging glass speakers look awesome!

First off, we know the question you’re already asking — how do they sound? Well, to be honest, not that bad! You could describe it as being glassy (ha ha), but you would be surprised how nice the bass comes through. The speakers suffer when it comes to treble though as it comes out a bit muffled. This could be corrected with a few strategically placed hidden tweeters though!

So how do they work? Well, like any speaker, the sound comes from vibration — in this case, the glass is vibrated to produce the sound. To achieve this, [Evan] is using a pair of HiWave HIAX32C20-8 tactile transducers, which are actually designed to turn most surfaces into speakers. The tricky part of this build is how to hang them.

Having limited space in his room, [Evan] opted to hang the speakers from the ceiling with wire — the only problem is drilling glass isn’t that easy. He shares a few tips, and eventually succeeded using a Dremel tool. From there it was just a matter of installing some hooks in the ceiling, and stringing it all together.

Check out the following video to hear them in action!

[Read more...]

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