Arduino MP3 Jukebox

Here’s an inexpensive Arduino-based MP3 Jukebox (translated) which [Jose Daniel Herrera] put together.

He spent some time making sure that it looked great sitting on a shelf with his other audio equipment. This started with a wooden box which is some reused packaging. We’re not familiar with the ‘iNFUSiONES’ product; perhaps it’s tea or tobacco? At any rate, to this he added a custom face plate to host the character LCD, rotary encoder, two buttons, and to act as a grill for the two speakers.

The speakers and their accompanying amplifier circuitry were pulled from a portable speaker set. He combined them with a VS1002d MP3 decoder module, SD card breakout board, and the Arduino itself. In addition to the overview post linked above, there is also a collection of assembly photos, and a post discussing the way he arranged the code for the control systems (translated). See and hear the unit in action in the clip after the break.

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More CRT fun with the Scope Clock

That’s a sexy way to use parts from an old oscilloscope. [Aaron] took his inspiration from another project that was using CRTs from old oscilloscopes. Now he’s giving back with a site dedicated to sharing information about the Scope Clock. This project is along the same lines as the one we saw a few days ago.

The image above shows his first build in its new home in Hong Kong. The clock is housed in two clear acrylic containers, paired through a surprisingly beefy military grade connector. You can see the journey that it took to get to this polished finish by going to the Prototype tab at the top of the page linked above. One of the images shows some fast captures of the screen redraw. It lets you see the vectors which are being traced on the phosphor screen by the electron gun. This gives an image that we think is far more pleasing than the row scanning of a traditional CRT monitor.

Of course you don’t have a to start from scratch either. Here’s a clock project that just augments a functional CRT scope.

Hands free hot air station

In an effort to ease the process of soldering Ball Grid Array (BGA) chips at home [Roger] rigged up a hands-free solution for his hot air equipment.

The main component in the build is an Aoyue hot air rework station that he already had in his workshop. He wanted an adjustable mount that would hold it steady when reflowing parts so he hit Amazon and bought a $14 articulated lamp. After ditching the funnel-shaped shade he bolted a cable clamp to the socket housing. This can be tightened on the hot air wand, with the spring tension of the lamp making it easy and quick to reposition the nozzle. [Roger] sent this project directly to our tips line and we’ve embedded the rest of the project images after the break.

If you’re looking for a more DIY rework solution you should checkout this hot air pencil hack. It uses a desoldering iron, a fish pump, and some metal mesh as a heat sink to put out a stream of very hot air.

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Building a bipolar supply from a boost converter

This DC-DC Bipolar PSU was developed for use with a guitar effects pedal. [Obsolete Technology] needed to source both positive and negative 15V. This is pretty easy to do if you’re converting from mains, but he wanted a solution that could work with a lower-voltage AC/DC wall wort or even from batteries.

The part that pulls it all together is the LT3467. It’s a switching power regulator which offers a range of features configured by the layout of a handful of external passive components. It can put out 80 mA on each line (positive and negative). Also extremely useful for this application is the chip’s high frequency operation. Depending on the version, it switches at 1.3 or 2.1 MHz. This is high enough that it will not introduce audible noise into the audio system.

We’ve got an exercise bike whose negative supply for the LCD is blown. We’re going to try build this circuit, trimming it for our voltage needs, and get the contrast working again.

[Thanks Olli]

Measuring SMD parts with a home brew version of Smart Tweezers

SMD parts are great; they allow you to pack more parts on a board, do away with drilling dozens of PCBs, and when done correctly can produce a factory-quality board made in a home lab. There’s one problem with SMD parts; troubleshooting and measuring them. The ideal solution would be something akin to the Smart Tweezers we’ve seen before, but this fabulous tool costs three hundred bones. [Kai] came up with a much cheaper solution: home brew smart tweezers that can be built for a tenth of the cost as the professional model.

What [Kai] built is an LCR meter, basically a tool that measures inductance, capacitance, and resistance in a very, very small form factor. The technique of measuring a part’s properties involves feeding a set frequency into the device and measuring the phase, voltage and current coming out. It’s all wonderfully explained by [Dave] over at EEVblog in one of his earlier videos.

The hardware [Kai] is using includes an LCD display from a Nokia phone, an MSP430-based microcontroller, a very tiny opamp near the tip of one of the points of the tweezer, and a programmable gain amplifier used to measure the components. In testing, [Kai] can measure very low-value components with a +/- 2% accuracy, and larger, more realistic components with +/- 0.25% accuracy. An awesome accomplishment, and much better than the common Chinese meters that can’t measure in the nH/pF/mΩ range.

[Kai] hasn’t gotten his pair of smart tweezers working yet – he still needs to get the circuit up and running and write some software. We’ll keep our readers apprised of [Kai]‘s progress, though, and gently convince him to work with Seeed Studio or someone similar to get his version of Smart Tweezers onto maker’s workbenches the world over.

Nyan Cat built into the wall of a house

You’re going to need your best negotiating skills if you want to convince your significant other to let you add your own Nyan Cat to the kids’ room. This goes a bit deeper than just mounting something on the wall. The LEDs which light up this Nyan Cat installation are actually in the wallboard itself.

Luckily, this is actually a ‘playground for grown-up kids’. [Schinken] and his fellow hackerspace members built it at their location in Bamberg, Germany. It started as a Nyan Cat scarf, which was easy enough to hang on the wall. To make it sparkle they added sixteen LEDs. But you won’t see the wires from either side. A hole was drilled at the location of each diode, with a trench chiseled between them. This makes room for the wires, and was covered with spackle before painting. It turned out to be a pretty simple way to add a focal point to the room, and it certainly has the appropriate level of geekiness for a hackerspace.

Developing with eBay-sourced ARM + LCD dev boards

eBay isn’t only about counterfeit designer handbags and boxes of all-marshmallow Lucky Charms, sometimes there’s actually something useful for sale. [Matt] found a bunch of Chinese-made ARM development boards with integrated LCD displays on the ‘bay, but without a reliable toolchain, these boards – as cool as they are – are nearly useless. Thankfully, he figured out how to do something with these boards, and neatly packaged everything into a VirtualBox image.

The boards in question usually include a 2.4″ or 3.2″ touch panel LCD, an STM32F103 ARM Cortex-M3 CPU, a microSD card connector, and sometimes a few other goodies like 16MB of Flash memory and an RS-232 port. An amazing amount of computational capability packaged into an easy-to-use form factor made even more awesome by their $40 price point.

Because these boards offer so much more than a common Arduino, a proper OS is in order. [Matt] looked over FreeRTOS and included a few demo programs for his Ubuntu-based VirtualBox image (available for download on [Matt]‘s site, it’s a dropbox, email us if you need some hosting, [Matt]) Never mind, see below.

Programming these boards can be done over a serial interface, but a JTAG programmer such as a Bus Blaster makes things very, very easy.

You can check out a few demos [Matt] put together after the break. It’s a very cool development that is much more suited for being integrated into an electronics project than a Raspberry Pi or other such high-power ARM board, and something we hope to see more of in the future.

EDIT: You know what’s really good for hosting Linux distros? Torrents. That’s [Matt]‘s distro and the HaD crew is seeding. Please seed.

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