Get Blown Away by the Boominator

You have a greater chance of squeezing 5 amps through a 2N2222 than you do remembering the 1980s and not thinking about the legendary ‘boom box’. They could be seen perched on the shoulders of rockers and rappers alike – many sporting the Members Only or red leather jackets. The boom boxes visual characteristics can best be described as a rectangular box with two very large speakers on each end. It is no accident that The Boominator shares these features.

[Jesse van der Zouw] did a good job of showing how he created The Boominator. It has not two, but four 10 inch woofers that delivers 360 degrees of awesomeness at 115dB. The on board battery can sustain it for up to twenty hours, and the project is topped off with some blue LED rings the encircle each speaker.

We’ve seen boom boxes here before, but this is the first with some nice LED accents. Be sure to check out this build and let us know what you might have done differently.


DIY Speaker Build

There is something refreshing about a neat, portable audio hack – especially one than involves making a DIY Speaker Box from scratch. [Dave] had some time to spare and his ShapeOko was lying idle and hankering for some attention. He needed a small speaker that he could place outside when entertaining guests. After some quick homework, he zeroed in on the speakers he would use.

Using some online resources , he did some basic math to figure out the box size and shape, but then eventually threw caution to the wind and went ahead with the design he had in mind. Most speaker box builds use some form of wood or MDF. [Dave] had 9mm thick ABS sheets lying around and decided to use them instead. He used an interesting technique for putting the box together. The front and rear panels had slots milled in to them to follow the shape of the side panels. The two side panels had strategically cut slots half way through the thickness of the ABS to make it easier to heat bend them. He then used a heat gun to bend the side panels to fit them to the slots on the front and back panels. In the end, we’re guessing he used just four pieces of ABS to build a complex shape. Since the HiVi B3N speakers are full range, he also built a 1st order crossover to make sure the highs were diverted to the tweeters. All in all, a neat, clean build.

DIY Custom Molded Earbud Roundup

Headphones have become ubiquitous these days. Thanks to the iPod and the smartphone, it’s become commonplace to see someone wearing a pair of earbud style headphones. Earbuds aren’t always comfortable though. On some people they are too loose. On others, the fit is so tight that they cause pain.To that end, we’ve found a few great solutions for this problem.

[cptnpiccard] has documented his custom molded Sugru earbuds in an Imgur gallery. He’s molded a pair of standard earbuds into a cast of his ear. He uses them both for hearing protection and tunes while skydiving. Sugru’s FAQ states that while the cured material is safe for skin contact (and in ear use) some people are sensitive to the uncured material.

While discussing his project on Reddit, a few users chimed in and mentioned they’ve made custom molded earbuds using Radians custom earplug kits. The Radians material hardens up in only 10 minutes, which beats waiting an hour for Sugru.

The absolute top of the food chain has to be building your own triple driver in ear monitors, which is exactly what [marozie] has done. Professional custom molded monitors can cost over $1000, which puts them in the realm of professional musicians and audiophiles. [marozie] discovered that mouser stocks quite a few transducers from Knowles. These tiny speakers don’t come cheap, though; you can spend upwards of $70 just for a single driver.

[marozie] took a cast of his ear using an earmold impression kit. He used this cast to create a mold. From there it was a matter of pouring resin over his carefully constructed driver circuits and audio tubes. The resulting monitors look and sound incredible.

It goes without saying that making custom in ear monitors involves putting chemicals into you ears. The custom earmold kits come with tiny dams to keep the mold material from going in too far and causing damage. This is one of those few places where we recommend following the instructions. Click past the break to see a demo video of the ear molding process.

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Super Simple FM Transmitter

Making your own FM radio is practically a rite of passage for hackers. How about making a small FM transmitter?

Originally designed by the Japanese multimedia artist [Tetsuo Kogawa], this simple FM transmitter can be built with only 10 components and about an hour of your time. The method shown here is one of the easiest to build, and it’s called the Manhattan Style — the same method used when [Bill Meara] built his BITX radio. It’s unique in that instead of using traces it uses one copper PCB which is used for all ground connections, and then small islands of the same PCB glued on top to form nodes for the circuit to connect to. Besides being an extremely easy way to make a PCB without any fancy tools, it also makes you think about circuits in a different light. In fact, it gives “floating ground” a whole new meaning!

While its 10 component count is impressive, it can’t beat this 3 component FM transmitter we shared a year ago! Stick around after the break to see how to make your very own.

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Bass Bump Headphone Amp


Headphone amplifiers make for simple, practical electronics projects. The Bass Bump Headphone Amp is no exception, since it’s made out of easy to source parts, and can be built on a proto-board.

We’ve seen many variants of the classic cMoy amplifier, including this pretty one. The Bass Bump differs by providing control over bass frequencies. It does this by putting a filter in front of the amplifier, with a potentiometer to select the mix of frequencies. This goes into a LM386 audio amplifier. At the output is a Zobel network to keep the impedance low at high frequencies. The amplifier can be powered from either a 9V rechargeable battery, or a USB port.

It’s a simple build, but definitely a good one to try on a rainy day. The write up explains how the analog circuitry works, and gives you full instructions on how to build it. After the break, check out a video overview of the project.

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A crystal radio amplifier in a jar


The cool thing with crystal radios is that they are solely powered by the incoming radio waves. However, it usually means listening to your AM radio station with an earpiece and even then, depending on the antenna length, ground connection, and radio station, it can be quite hard to hear.

Even though it is cheating, [Steven] decided to make an amplifier for all the different crystal radios he had made over the years. His design, based on an LM386 amplifier was firstly tested on a breadboard and then permanently soldered onto a perfboard. To make the complete system easy to transport, he opted for a peanut butter jar where he embedded the speaker in the cap. The on/off switch and volume controls are mounted on the side, and easy alligator clips are used for the antenna connection.

The final result is not the one shown in the picture above as [Steven] painted the jar black, giving it a sweet look.

GPS audio tour brought to you by surface speakers

The team at Eschelle Inconnue wanted to “trace a sound cartography of Islam” in Marseilles, France, so they came up with a clever little GPS walking tour powered by an Arduino, MP3 playback module, and a surface transducer speaker.

The team used a Processing app to define geographic areas where each MP3 file would play. An Arduino on the build queries a GPS module and selects the audio file from an MP3 playback module. This isn’t uncommon, and a lot of large outdoor museums (think battlefields) have similar setups.

Determining which audio to play at what location is fairly easy, but that’s not what makes this build special. Instead of simply hooking up a pair of headphones to the build, the team decided to use a surface speaker that turns just about any solid material into a speaker. From the writeup, this is supposed to, “diffuse sounds by giving the illusion to collect them, to listen to the words of the walls, the whisperings through the materials” but we think it’s just a great way to have several people listen to the same audio file at the same time.