Surround Sound system controller replacement includes home automation

[Neoxy] always wanted surround sound for his computer, and one day he managed to get a hold of a dead 5.1 system. Why buy one when you can repair someone’s rubbish, right? That turned out to be easier said than done, but after several false-starts he managed to resurrect the audio system by replacing the microcontroller.

We find his trouble-shooting technique interesting. The amp would power up without a hitch but no sound would come out of it. So he took a headphone cable and used the L and R conductors as probes. That cable was fed from an MP3 player, and by touching the probes to the audio inputs for the pre-amp and amplifier circuits he could get great sound out of the speakers. Reasonably certain that those boards were working fine he narrowed down the troubles to three chips that mix, select inputs, and control the system.

A lot of prototyping with an ATmega328 and an Arduino led him to the functionality you see in the video after the break. Not only did he get the system working, but he’s using the Arduino to add Internet control for the device.

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Upgrading a Rockford Fosgate Punch 601s to an 801s with just a handful of parts

[Simon] had a Rockford Fosgate Punch 601s amplifier in his car, and while it was a great piece of equipment, he wanted a little more power behind his stereo system. It turns out that with just a handful of parts and a bit of soldering work, he was able to increase his amplifier’s output by 200 watts, putting it on par with a Punch 801s.

The main board in each amp is laid out identically, making the conversion a relatively easy process. A handful of MOSFETs need to be added, along with some resistors and capacitors. Most of the work can be done with a decent soldering iron, though you might want a hot air reflow station to handle the smaller resistors – it all depends on your skill set.

We’re really not sure how big the price difference is between the two amps, but we’re pretty certain that the conversion would be worth it. [Simon] sells conversion kits on his web site for under $60, but you may be able to find the parts for a bit less if you hunt around.

Creating music from GPU noise

Yep, that’s a picture of a Laptop rocking out on an electric guitar. In what can only be described as a truly bizarre hack [CNLohr] discovered that the RF noise from the computer can be used to play music through the guitar’s pickup.

Check out the clip after the break to hear an annoying, but very discernible rendition of Jingle Bells. Once [CNLohr] stumbled onto the fact that changes in what the graphic processing unit is doing was affecting the pitch detected by the pickup he started writing some code. Now he’s got a program that automatically calculates the size of the window, and produces a white square on a black background to dial in the GPU at the right frequencies.

He mentions in the notes accompanying his video that he had to turn off Vsync to get this to work right. We don’t understand why but we’d love to hear what you think in the comments.

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Don’t buy an amp, build one to suit

In need of an amplifier for his home entertainment system [Afroman] decided to build an amp rather than buying one. If nothing else, doing it himself allowed for a form factor that can’t just go out and buy.

He designed the project on two separate boards, one for the power supply and the other for the amplifier circuit. Both are of his own design, and although he doesn’t share the schematic, we know he’s based his work on a National Semiconductor reference design for the LM4780 audio amplifier chip. There’s a few other clues, like his mention of the toroidal transformer seen at the left in the image above and hi-res photos of the unpopulated board that has component values printed in the silk screen.

The final design allows him to get great performance out of his speakers with a very clean look. You’ll need to be logged to the forum linked above to view all of the images, but we’ve embedded three more of them after the break to whet your appetite.

Oh, and cost? This gets up there, just sneaking past the $500 mark.

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More 555 Projects to Enjoy

We love all of the projects that are coming out for the 555 design contest, so we thought we would share a couple more that have caught our collective eye.  Have a 555 project of your own? Be sure to share it with us, and keep an eye out for the contest submission dates. Read on for a few of our project picks.

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Audio cabinet refit with modern equipment

Hard at work on making this 1960’s Fleetwood audio console usable again, [Travis] packed a lot of power into the retro case. Both the radio and turn table had stopped working but the cabinet looks great and the speakers still work. In the lower center cavity you’ll now find a full computer motherboard and replacement amplifier. A new turntable has been added with an interesting vibration-dampening shelf to support it. [Travis] built the shelf with a void in between two layers of wood which he filled with sand to help with isolation. The remote control for the amp also needed some work as the receiver is pointed to the back of the unit. To fix that a second IR receiver found a home behind the fabric for one of the speaker grates. That receiver is monitored by an ATmega168 microcontroller and signals are repeated back to an IR LED mounted near the amplifier.

1953 Radio includes tubes, AM, FM, and MP3

This vintage radio can play AM, FM, and MP3, all with a classic sound. Inside you’ll find a new AM radio tube-amp, providing the functionality you’d expect from the device. The rest of it comes from a conglomeration of parts; an FM receiver board from another radio and an MP3 player with remote control and USB connector. The classic sound we mentioned above comes from an AM modulator. That’s right, the auxiliary audio boards aren’t connected directly, but are broadcast on the AM band so that your latest MC Lars album has the same sound quality as the traffic report.

Check out this similar project from last year that adds RDS to a vintage radio.