Year: 2012

Measuring How Components React To Extremely Cold Temperatures

July 22, 2012 by 8 Comments

[Shahriar Shahramian] is playing with some liquid nitrogen in order to see how various components react to extremely low temperatures. After the break you will find forty-one minutes of video in which he conducts and explains each experiment. This does have practical applications. If you’re designing hardware for use in space you definitely need to know how the hardware will be affected. We’ve actually seen test rigs built for this very purpose.

During the presentation he doesn’t water down the concepts observed, including the equations governing each reaction to temperature change. If you’re in the mood for a little bit lighter faire you should check out some of the liquid nitrogen cooking hacks like this super-cold cocktail pops project.

 

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Task Scheduler For Arduino

July 22, 2012 by 20 Comments

For their recent high altitude balloon project LVL1 member [Brad] programmed a pretty complicated brain based on an Arduino. It was responsible for collecting data from all of the sensors, and reporting back in a few different ways. One of the things he did to simplify the project was develop a task scheduler for the Arduino board. It lets you add functions to a queue of jobs, along with data about when they should be run.

The task scheduler does make coding a bit easier, but where it really shines is in situations like this where you don’t have access to the hardware if there’s a problem. In his description of the scheduler [Brad] mentions the possibility that one of the sensors could fail as the cold of the upper atmosphere takes its toll. This could leave the whole system stuck in a subroutine, and therefore it will stop sending reports back to the team on the ground. Since he was using the task scheduler it was a snap to add watchdog timer servicing to the mix. Now if program execution gets stuck the watchdog will reset the chip and all is not lost.

[Thanks  JAC_101]

Reverse Engineering A Stylophone

July 22, 2012 by 10 Comments

The Stylophone – a musical toy from the 60s – is a surprisingly simple piece of engineering. With a simple metallic keyboard played with a stylus and just a handful of transistors, the Stylophone was able to produce a few marvelous for their time sounds, and is the equivalent of a pre-[Stradivarius] violin for the electronic music scene. [Simon] tore apart an original Stylophone, and did a complete teardown of the circuit, going over the ins and outs of why this ancient noise box is so cool.

There have been quite a few DIY Stylophone clones, but all of them suffered from the same raspy sound made by a 555 timer chip slightly misguided makers used instead of the relaxation oscillator (in the pic seen above) used in the original. Aside from the oscillator connect to the RC circuit of the metallic keyboard, [Simon] also looked into the vibrato circuit. This is just a simple oscillator producing an 8 Hz sine-ish wave. The keyboard, of course, is connected to the circuit with an array of resistors which [Simon] happily provided the values for.

[Simon] put up a schematic of his reverse engineered Stylophone, allowing you to clone this ancient electronic instrument. If you can source the transistors, that is.

Editing Your FPGA Source

July 22, 2012 by 18 Comments

[Dave] noted that in a recent poll of FPGA developers, emacs was far and away the most popular VHDL and Verilog editor. There are a few reasons for this – namely, emacs comes with packages for editing your HDL of choice. For those of us not wanting to install (and learn) the emacs operating system, [Dave] got Notepad++ to work with these packages.

Notepad++ already has VHDL and Verilog highlighting along with other advanced text editor features, but [Dave] wanted templates, automated declarations and beautification. To do this, he used the FingerText to store code as snippets and call them up at the wave of a finger.

As [Dave] writes his code, the component declarations constantly need to be updated, and with the help of a Perl script [Dave] can update them with the click of a hotkey. Beautification is a harder nut to crack, as Notepad++ doesn’t even have a VHDL or Verilog beautifier plugin. This was accomplished by installing emacs and running the beautification process as a batch script. Nobody can have it all, but we’re thinking [Dave]’s method of getting away from emacs is pretty neat.

Servos, Servos, And More Servos

July 21, 2012 by 22 Comments

For one reason or another, a lot of Hackaday readers are doing stuff with servos as of late. Here’s a few servo hacks that made their way into our tip line over the past day or so:

USB servo controller and a Stewart Platform

[Patricio] needed a way to control a bunch of servos for his thesis project. He came up with a USB servo controller (Spanish, here’s the translation) powered by a 40-pin PIC 18F microcontroller. The board connects to the USB port of a computer and supports up to 8 servos with 8 additional digital I/Os. Why all this horsepower? It’s for a Stewart Platform [Patricio] and his partner [Natalia] built.

Continuous rotation servos

Standard servos are usually limited to a rotation angle of somewhere between 140 and 160 degrees. Sometimes you need a continuous rotation servo, and those are a little more expensive. Every servo is a continuous rotation servo if you disable a the variable resistor as [Valentin] shows us. It’s a simple, if old, hack. It’s new to someone, though.

Eight servos on a Raspi

[Mikael] made a little board to attach to the GPIO header of his Raspberry Pi and control up to 8 servos. The board is running a serial interface with a small microcontroller on board. There’s nothing in the way of schematics or code, a testament for why you should always use a good email address when sending something into the HaD tip line. It seems [Mikael] is making a proper board, and we’ll more than happily give it a full post when it’s complete.

Chorded Keyboard For Touchscreens

July 21, 2012 by 18 Comments

For over a hundred years, good typists didn’t ‘hunt and peck’ but instead relied on keeping their fingers on the home row. This technique relies on physical buttons, but with on-screen keyboards used on tablets and other touch screen devices touch typists have a very hard time. [Zach] is working on a new project to bring a chorded keyboard to these devices called ASETNIOP.

Instead of training a typist where to place their finger – the technique used in most other keyboard replacements, ASETNIOP trains the typist which fingers to press. For example, typing ‘H’ requires the typist to press the index and middle fingers of their right hand against the touchscreen. In addition to touchscreens, ASETNIOP can be used with projection systems, Nintendo Power Glove replicas, and extremely large touchpads that include repurposed nooks and Kindles.

If you’d like to try out ASENTNIOP, there’s a tutorial that allows you to try it out on a physical keyboard as well as one for the iPad. It’s a little weird to try out but surely no more difficult to learn than a Dvorak keyboard.

Building Fiber Optic Chandeliers

July 21, 2012 by 8 Comments

This chandelier keeps the light source hidden and uses fiber optics to illuminate the acrylic diffusers. It’s the second attempt [TheCreator] has made at building his own. Bother projects are interesting in their own way.

The first attempt used marbles as diffusers and had a much different look to it. This time around he’s using what he calls acrylic dowels. They’re not round, but square (which is why we’re not sure dowel is the right term), and he says they work better than marbles for several reasons. The marbles weren’t very heavy so they didn’t really weigh down the glass fibers to keep then straight. They were also difficult to attach to the fibers and prone to breakage.

To attach the dowels he drilled a hole in the end and epoxied a fiber optic strand in place. To direct light into the other end of the filament he built his own frustum (a pyramid with the tip cut off) of inward facing mirror. This helps to focus what is coming from the RGB LEDs in the appropriate direction so that as much light as possible makes it into the fibers.

He didn’t really give any final thoughts so we wonder if it puts out enough light for his needs. We’re sure that if it’s purely a mood piece he’s satisfied.