A lot of awesome stuff happened up in [Bruce Land]’s lab at Cornell this last semester. Three students – [Pat], [Ed], and [Hanna] put in hours of work to come up with a few algorithms that are able to simulate stereo audio with monophonic sound. It’s enough work for three semesters of [Dr. Land]’s ECE 5030 class, and while it’s impossible to truly appreciate this project with a YouTube video, we’re assuming it’s an awesome piece of work.
The first part of the team’s project was to gather data about how the human ear hears in 3D space. To do this, they mounted microphones in a team member’s ear, sat them down on a rotating stool, and played a series of clicks. Tons of MATLAB later, the team had an average of how their team member’s heads heard sound. Basically, they created an algorithm of how binarual recording works.
To prove their algorithm worked, the team took a piece of music, squashed it down to mono, and played it through an MSP430 microcontroller. With a good pair of headphones, they’re able to virtually place the music in a stereo space.
The video below covers the basics of their build but because of the limitations of [Bruce]’s camera and YouTube you won’t be able to experience the team’s virtual stereo for yourself. You can, however, put on a pair of headphones and listen to this, a good example of what can be done with this sort of setup.
Continue reading “Adding stereo to monophonic audio”
We like the look which [Emmanuel] achieved with his Raspberry Pi based Squeezebox client. It’s got that minimalist slant that makes it seem like a commercial product at first glance. But one more look at the speakers without grates, the character LCD, and the utilitarian buttons, knobs, and switches tips us off that it’s filled with the hardware we know and love.
Since Logitech announced that it was terminating the Squeezebox line we’ve seen several projects which take up the torch. We’ve seen the RPi used as a Squeezebox server and several embedded Linux systems used as clients. This follows in the footsteps of the latter. The RPi is running Raspbian with the squeezelite package handling the bits necessary to talk to his server. The controls on the front include a power switch, rotary encoder and button for navigating the menus, and a potentiometer to adjust the HD44780 LCD screen’s contrast. The speakers are a set of amplified PC speakers that were liberated from their cases and mounted inside of the wooden box that makes up the enclosure. The in-progress shots of that case look pretty rough, but some sanding and painting really pulled everything together. As you would expect, we’ve embedded the demo video after the jump.
Continue reading “SqueezeBerry: a Raspberri Pi powered Squeezebox appliance”
[Ivan] made something special with this car stereo hack. He altered the head unit to play MP3 files from USB and added an auxiliary line-in. But looking at it you’d never know. That’s thanks to the work he did to create a false button hiding the audio jack, and a false cassette hiding the USB port and MP3 player display. Possibly the best part is that the radio itself still works like it always did.
There are several components that went into making the system work. It starts with the cassette/radio head unit. To that he added an MP3 player with remote which he picked up on Deal Extreme. He wasn’t a huge fan of the IR remote that came with it so he rolled in a remote that mounts on the steering wheel. To pull everything together he used a PIC 16F877a. The microcontroller controls the lines which tell the head unit if a tape has been inserted. When [Ivan] selects either the Aux input or wants to play MP3s from a thumb drive the uC forces the head unit into cassette mode and the audio from the player is injected into the cassette player connections.
To help deter theft [Ivan] created two false fronts. The end of a cassette tape plugs into the USB port. The rewind button plugs into the Aux jack. You can get a good look at both in the demo after the break.
Continue reading “MP3/USB/Aux hack hidden behind cassette facade”
With summer on the horizon it’s time to start thinking about outdoor leisure. [x2Jiggy] is chomping at the bit having recently completed this project. It’s a portable stereo that also gives you somewhere to sit.
Unlike several of these types of project, he didn’t build the system inside of a cooler. Instead, the chassis was built from scratch using MDF. This material is strong and easy to work with, but we’d bet the finished case is a beast to haul around because of the weight. At least there’s a heavy-duty handle on either side so that you and a buddy can split the burden. One nice perk is that it’ll make a sturdy yet comfortable seat thanks the padded and upholstered top.
The audio components that went into it are all automotive parts and shouldn’t mind being jostled during transport. A computer PSU provides the 12V needed by the stereo. But there are a couple of external rail connections if you want to haul around a 12V battery instead.
This is [Wpqrek’s] Commodore 64 modified to go on the road with him. The elderly machine has a special place in his heart as it was what he learned to code on. He performed a series of hacks which house everything necessary to use the machine inside the original case.
Obviously the hack that has the most effect when it comes to portability was swapping a display for the small LCD mounted above the number keys. This was a pretty simple process because the screen, originally intended for a rear view camera in a vehicle, already had a composite video input. To emulate the floppy disc drive he’s using an SD card via an sd2iec board which he laid out himself. Rounding up the alterations is a stereo SID. The second channel uses the pre-amp circuit cut from a second C64. This audio hardware will let him do cool things like playing some classic Zeppelin.
You can get a video tour of these alterations after the break.
Continue reading “Making a Commodore 64 portable”
[Michael] wanted a stereo that he could use outside, be it at the beach, beside the pool, or while tailgating. He decided to build this boom box himself, and didn’t cut any corners when it came to a professional looking finish.
Because of the locale in which he plans to use the stereo he went with a set of marine speakers. They’ll have no problem standing up to water, and since they’re used in boats they should also be able to take a beating during transport. To feed it he uses a Lepai T amp which is seen above.
After cutting each piece of the case out of MDF he started working on the openings to receive the components. This involved quite a number of layout lines and some work with a compass to map out the circular openings. He built a recessed panel on the back to interface the power cord for charging. Inside is an 18 Ah battery. A set of switches lets him turn on the charger and choose between powering the amp from battery or from the power cord.
Here are two different briefcase speaker projects. [Dale] built the offering on the right back in high school and the upgraded version 2.0 more recently. He was inspired to send in a tip for the projects after seeing yesterday’s suitcase full of tunes.
The first version uses a pair of speakers pulled out of a car at the junkyard. They’re mounted on some particle board which beefs up the side of the plastic briefcase. The amplifier that drives it is mounted inside the case along with a battery to power the system. [Dale] included a crude storage bracket for the input cable and since the amp can drive four speakers there are connectors on the outside for two more.
Version two has quite a bit more polish. He doesn’t show that one off quite as much, but you can see there is a LED strip on the case that serves as a VU meter, as well as a numeric display which might be battery voltage? He mentions that this blows away any commercially available systems his coworkers have brought to the job site.
Video of both rigs can be found after the break.
Continue reading “A pair of briefcase boombox builds”