A Folded Horn Enclosure To Make The Most Out Of A Subwoofer

November 26, 2012 by Mike Szczys 42 Comments

To make the most out of his home theater sound system [Baccula] built this folded horn enclosure for as much bass sound as possible. The design was conceived by [Bill Fitzmaurice] who thought there needed to be a better way to use the subwoofers which are typically used in home systems. His design is called the Tuba HT and it is aimed at a 15″ speaker. [Bill] charges for the building plans, but we don’t mind living vicariously through [Baccula’s] construction album.

As you can see, there are a lot of wood parts that went into the cabinet. It starts with a base of 2×4 framing. From there the plywood sawdust really starts to fly as each component is produced. During assembly [Baccula] is careful to fully glue each joint — you don’t want to find out that your sub cabinet vibrates after you get everything installed. All together the new piece of living room furniture stands three feet tall and deep and two feet wide.

The album has no captions but you can read a bit more about the project in the Reddit comments.

Android VOIP Phone And Raspberry Pi Mate For An Intriguing PBX Setup

November 26, 2012 by Mike Szczys 5 Comments

[Ward Mundy] has found something great by combining a GXP-2200 phone with Raspberry Pi to create a private branch exchange. So the idea behind a PBX setup is kind of like a company intranet. All of the phones in the system are assigned an extension number and have access to the internal system functions like voice mail, and sharing phone lines to the outside world. We’ve talked about using an RPi as a PBX before, but the high-tech phone he’s using this time around pulls everything together remarkably well.

The GXP-2200 is available for under $200. It runs Android and has a full color touch screen pictured above. It is marketed as a multimedia phone and indeed it brings Skype and Google Voice to the party. But it also offers six SIP lines. The hardware even seems to be planned for this type of use as the phone offers a second Ethernet port to which the RPi board can be connected. In this example [Ward] simply screws the RPi to the phone’s plastic stand and connects the two using a six-inch cable. From there the PBX can be configured with the phone’s browser. How’s that for slick?

Personal Cooling Using A Closed Loop Water System

November 26, 2012 by Mike Szczys 38 Comments

That’s not a colostomy bag, it’s the first prototype of [Stephen’s] scratch-built closed loop personal cooling system. He must be living in an uncomfortably hot apartment as this is the second cooling system we’ve seen from him in as many weeks. The previous offering was an evaporative system. This time around he’s pumping chilled water to bring some relief.

The image on the left shows the first iteration of the system which pumped cool water from a large jug through a loop of plastic tubing which he wears around his neck. To refine the design he build the version on the right. As a reservoir he grabbed a water-proof ID container meant to keep your valuables dry in the pool or ocean. Inside there’s a pump which he runs off of a 5V battery supply. It circulates water through the neck strap which is a piece of plastic tubing.

This will work for a time, but as the cold water picks up your body’s heat the effect will be lost. We think he needs to add a Peltier cooler to the reservoir in the next iteration. It might help to refine the loop to increase its ability to transfer heat where it touches your skin.

There’s demo of the most recent version embedded after the break.

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$5 Toy Car Upgraded To Record The Ride In HD

November 26, 2012 by Mike Szczys 14 Comments

We hope [Kabir’s] driving skills are top-notch because the camera stuck to the front of this toy is a high-ticket item. It’s ironic, since the donor toy for this hacked RC car only cost about five bucks. It had been gathering dust in the dark reaches of his bedroom until he sat down and gave it a proper upgrade.

He started the project by getting rid of the stock battery and moving to a pair of Lithium Polymer cells. They give the vehicle more power and more than twice the running time between charges. A couple of springs were added to the suspension system for a smoother ride. Turning had been a problem since the original design offered no control over how far the wheels turn. You can just make out the body of the servo motor he rolled into the system to allow for more precise turning.

The most recent addition is the HackHD camera on the front of the vehicle. It records to an SD card rather than streaming the video in real-time. Check out the clip after the break to see the interesting perspective achieved by filming so low to the ground. The one thing we would add is a cage around that board which retails at around $165.

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Minecraft Coming To Raspberry Pi

November 26, 2012 by Eric Evenchick 18 Comments

The folks over at the Raspberry Pi Foundation often gets asked “does it run Minecraft?” Mojang, the team behind the block building game, has announced that they will be releasing Minecraft: Pi Edition. This port will be based off the Pocket Edition of the game, but with a revised set of features.

So what does this have to do with hacking? Mojang has announced that the Pi Edition will have “support for multiple programming languages.” There aren’t too many details about what this support will entail, but it looks to be aimed at teaching programming by using the world of Minecraft.

Hopefully, it will be possible to interface with the RPi’s expansion header to allow external devices to get data and create objects in the Minecraft world. There’s a lot of potential for hacking and learning programming skills.

The best part? It will be a completely free download. We’re looking forward to the launch.

Abstracting Transistors Into High-level Design

November 26, 2012 by Brian Benchoff 10 Comments

Although it’s not the best way of understanding computers, most people tend to imagine electronic devices as black boxes filled with magic and blue smoke. Even microcontrollers, the most fundamental means of computation, are treated like little black plastic centipedes with metal legs. In a series of blog posts, [Andrew Gibiansky] is tearing down the walls of obfuscation and illuminating the world of transistors, gates, and FPGAs.

The first blog post goes over the idea of electronic circuits as a waterfall; a positive voltage is a reservoir on a mountain top and ground is sea level. This idea is extended to the lowly transistor acting as an electronic switch, able to turn a circuit on and off.

Continuing on to logic gates, [Andrew] covers the NOT, AND, and OR gates before moving on the flip-flops and SRAM. These can, of course, be modeled in Verilog and VHDL – programming languages that abstract the world of transistors and gates into a much more human-readable form.

[Andrew] is far from done with his series of blog posts, but judging from his work so far it seems to be a great resource for untangling the obtuse concepts of gates and memory into the coherent design of a computer.

USB Keyboard Becomes An AVR Programmer

November 26, 2012 by Eric Evenchick 21 Comments

[Steve] created an AVR programmer using an old USB keyboard. We feature a bunch of AVR programmers, but this one is made from parts that many people will have lying around. There are two components: the controller PCB from a USB keyboard, and an optocoupler for emulating key presses.

In order to send data to the AVR, [Steve] used the LED outputs on the keyboard. These LEDs can easily be toggled according to the HID device specification. They provide a 5 volt output with current limiting resistors, which means they can be connected directly to the target AVR.

Reading data is a bit more complex. The optocoupler tricks the keyboard into believing that a single key has been pressed, firing off a data transfer. The MISO pin on the AVR is connected to the row and column of the shift key, which is read by the driver.

On the software side [Steve] created an avrdude interface driver. This allows the programmer to be used with avrdude, just like any other programmer. [Steve] does point out that it isn’t the fastest programmer since the keyboard tries to debounce the MISO input, greatly limiting the speed. However, since it’s made from stuff you might have in your junk bin, it’s a neat hack.