Monthly Archives: March 2016

3D-Printed Case Turns Servo into Quality Linear Actuator

3D-Printed Case Turns Servo into Quality Linear Actuator

Micro servomotors are a hacker staple. You’ll find maybe four or five in an RC plane, while a hexbot build could soak up a dozen or more of the cheap and readily available devices. Unfortunately, long-throw linear actuators are a little harder to come by, so it’s nice to know you can 3D-print linear gearing for standard micro RC servos and roll your own.

Currently on revision 2, [Roger Rabbit]’s design is not just a quick and dirty solution. He’s really thought through the problems he observed with his first revision, and the result is a robust, powerful linear actuator. The pinion fits a trimmed servo crank arm, the mating rack is stout and stiff, and early backlash problems have been solved. The whole case is easy to assemble, and as the video below shows, the completed actuator can lift 300 grams.

We like [Roger]’s build process, especially the iterative approach to improving the design. We’ll stay tuned to see where it goes next – a continuous rotation servo for extra-long throws? While we wait, you might want to check out [Richard Baguley]’s recent primer on servos if you want a little background on the underlying mechanism.

Filed under: hardware, misc hacks

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The ATtiny MIDI Plug Synth

The ATtiny MIDI Plug Synth

MIDI was created over thirty years ago to connect electronic instruments, synths, sequencers, and computers together. Of course, this means MIDI was meant to be used with computers that are now thirty years old, and now even the tiniest microcontrollers have enough processing power to take a MIDI signal and create digital audio. [mitxela]’s polyphonic synth for the ATtiny 2313 does just that, using only two kilobytes of Flash and fitting inside a MIDI jack.

Putting a MIDI synth into a MIDI plug is something we’ve seen a few times before. In fact, [mitxela] did the same thing a few months ago with an ATtiny85, and [Jan Ostman]’s DSP-G1 does the same thing with a tiny ARM chip. Building one of these with an ATtiny2313 is really pushing the envelope, though. With only 2 kB of Flash memory and 128 bytes of RAM, there’s not a lot of space in this chip. Making a polyphonic synth plug is even harder.

The circuit for [mitxela]’s chip is extremely simple, with power and MIDI data provided by a MIDI keyboard, a 20 MHz crystal, and audio output provided eight digital pins summed with a bunch of resistors. Yes, this is only a square wave synth, and the polyphony is limited to eight channels. It works, as the video below spells out.

Is it a good synth? No, not really. By [mitxela]’s own assertion, it’s not a practical solution to anything, the dead bug construction takes an hour to put together, and the synth itself is limited to square waves with some ugly quantization, at that. It is a neat exercise in developing unique audio devices and especially hackey, making it a very cool build. And it doesn’t sound half bad.

Filed under: ATtiny Hacks, digital audio hacks, musical hacks

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Wooden Computer Case Adds a Touch of Modern

Wooden Computer Case Adds a Touch of Modern

When [LouisVW] decided to build a new gaming rig, he wanted to try something different. So instead of buying a pre-built tower, he made one — out of wood!

Coming from someone who has no experience in 1GNAWU0woodworking (or computer building) we’re seriously impressed with what he’s made. He was originally inspired to build the case when he saw boxes made by stacking pieces of plywood together — he got one and decided to turn it into a case.

Using a jigsaw, chisel and Dremel he was able to cut out all of the fan holes and drive bays fairly easily, and thanks to overlapping plastic covers it wasn’t that hard to make everything look perfect.

The part we’re most impressed with is that he made the motherboard mounting panel himself, instead of salvaging the panel from an old tower. Some acrylic side panels and LEDs later, and the rig is done!

When it comes to custom tower builds, this desk / computer tower combination has got to be one of our favorites!

[via r/DIY]

Filed under: computer hacks

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A Ridiculous Way to Light an LED: Candle-power

A Ridiculous Way to Light an LED: Candle-power

If you have ever entertained yourself by reading comprehensive electronic-theory textbooks you’ll have seen references to technologies that sound really interesting but which you will rarely hold in your hand. They may be dead-ends that have been superseded by more recent innovations, or they may be technologies that have found uses but in other fields from those in which they originally showed promise. What if you could take these crazy parts and actually build something?

[Fedetft] has an interesting project that combines two of those intriguing textbook references, he’s created a thermopile that lights an LED through an inverter whose oscillator is a tunnel diode. Dig out the textbook.

If you’ve used a thermocouple thermometer or a semiconductor thermoelectric generator then you’ll have encountered the thermoelectric effect. Perhaps you’ve even operated a Peltier cooling element in this mode. When a circuit is made with two junctions between different types of conductor with a temperature difference between the two junctions, a current will flow in the circuit which is dependent on both the scale of the temperature difference and the properties of the conductors.

A thermopile is a collection of these thermoelectric junction circuits between metal conductors, arranged in series to increase the voltage. [Fedetft]’s thermopile uses chromel and alumel wires taken from a K-type thermocouple. He’s made six sets of junctions, and supported them with small pieces of mica sheet. Using the heat from a candle he found he could generate about 200mV with it, at about 3.7mW.

The RCA tunnel diode inverter circuit
The RCA tunnel diode inverter circuit

Such a tiny source of electricity would be of little use to light an LED directly, so he needed to build an inverter. And that’s where the tunnel diode comes in. Tunnel diodes have a negative-resistance region that can be used to amplify and oscillate at extremely high frequencies in extremely simple circuits, yet they’re not exactly a device you’d encounter very often in 2016. [Fedetft] has a Russian tunnel diode, and he’s used it with a toroidal transformer in an inverter circuit he found in an RCA tunnel diode manual from 1963. It’s a two-component Joule Thief. The RCA manual is a good read in itself for those curious about tunnel diodes.

The resulting circuit produces a 15kHz oscillation with 4.5v peaks, and has just enough power to light an LED.

While it might seem pointless to barely light an LED from a brightly lit candle, the important part of [Fedetft]’s project is to gain some understanding of two of those technological backwaters from the textbooks. And we applaud that.

It’s the mark of a truly esoteric technology that it features rarely on Hackaday, and neither of these two disappoint. We’ve only mentioned tunnel diode in passing when looking at diodes in general, and we’ve tended to use “thermopile” in another sense to refer to thermal imaging cameras.

Filed under: led hacks, parts

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Life Organization: Gadgets vs. Gear

Life Organization: Gadgets vs. Gear

One of the things that gadgets allow us to do, so long as we let them, is to make our lives more efficient, manageable, and often just – smaller. But, sometimes that life organizations stages and phases we go through aren’t super clear about how to make this happen.

For those of you who are entering into one of those restructuring stages, consider the five following tips, including storing the big stuff, organizing the little stuff, using gadgets to increase overall life efficiency, creating a throw-away cycle, and being smart about updating gadgets in general.

Store the Big Stuff

Our past often carries with it a degree of bulk. This can be in the form of old books, old exercise equipment, old appliances, or even memorabilia. But if you really want to have an organized life, all that stuff that you don’t use regularly should go into a storage facility. You’d be amazed how much stress that clears up out of your mind when you’ve gotten rid of some of the bulky clutter and gear you’ve been saving over the years.

Organize the Little Stuff

Little stuff, when it comes to organizing, will probably get separated into two basic categories. There’s the stuff that you use regularly, like electronics gadgets you’ve collected over the years, and then there are accessories for those gadgets. Think cables, adapters, power supplies, cords, and all of those other knick knacks. If you organize all of those little things, then not only will they look less cluttered in the various aspects of your life, you might actually be able to find them when you need them next as well.

Use the Gadgets To Increase Efficiency

And built into your gadgets, such as your tablets and smartphones, are a vast array of organizational apps just waiting for you to dig into them. Even a short amount of energy spent organizing your time and your belongings in a way that makes sense as suggested by various apps can be a huge benefit.

Create a Use-It-Or-Lose It Cycle

If you haven’t used something in six months, you can probably just get rid of it. So many people hoard belongings ‘just in case’, but ultimately all that ends up doing is stressing you out because you still maintain the concept of value regarding things that are collecting dust around you.

Be Smart About Updates

Gadget updates – the physical ones, not the software ones – can be a big part of your life organization process as well. If the newly updated components, part or pieces of your gear will have a significant impact on your ability to organize your life, then why not jump right in with no regrets!

The post Life Organization: Gadgets vs. Gear appeared first on Gadzooki.



Gadget Hacks

Nanocounter: Frequency Counter with an Android UI

Nanocounter: Frequency Counter with an Android UI

Have you ever started a project, run into an issue, started a new project to solve the issue, and completely forgot about the original project? [Andy] went down a rabbit hole of needing a tool to calibrate an MCU oscillator, but not having an accurate way to measure frequency. Most people would just buy a frequency counter and be done with it, but [Andy] decided to build his own.

The Nanocounter is an accurate, open source frequency counter that uses an Android phone as its display. It’s based on a high accuracy temperature compensated crystal oscillator (TCXO) fed into a phase locked loop (PLL) to create a high frequency, accurate reference clock.

This reference clock, along with the signal to be measured, are sent into a Xilinx FPGA which uses a method called equal precision measurement to determine the frequency. A STM32F072 microcontroller uses a SPI interface to get this data out of the FPGA, and controls the whole system. Finally, a cheap HC-06 Bluetooth module facilitates communication with an Android device.

The project achieves the goal of frequency counting, though [Andy] doesn’t remember what project sparked the idea to build it. (Classic yak shaving!) But the result is a great read of a detailed writeup, and you can watch a video of the Nanocounter in action after the break. That’s a win in our book.

Filed under: tool hacks

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Bare Metal Media Centre

Bare Metal Media Centre

Sometimes, along comes a build that is simple and bare, and yet exemplifies “hacking” – an art form that uses something in a way in which it was not originally intended. We’ve featured a few Raspberry Pi builds, but this one is less about the Pi and more about putting the rest of the hardware nicely together. [Garage Tech] built this Raspberry-Pi Stand and the end result is brilliant.

MediaPlayerSide-6-5-4It is nothing more than a metal book holder – the kind you are likely to pick up a pair for a few bucks at a charity shop or flea market. He was lucky to also snag a JBL On Stage IIIP Speaker Dock for cheap. Quickly spotting an opportunity, he decided to put together an OpenELEC based media centre using his bounty. Having made up his mind, he needed a couple of other parts to make sure this build looked, and sounded, good. An iQuadio Pi DAC+ , the Pi-DAC+ case from ModMyPi which comes with all the necessary hardware, and the official DSI touch screen.

With all of the stuff on hand, the rest of the build involved a short time at the workbench drilling some holes and slots in the aluminium book holder plate to mount the Pi-DAC case and the display. He drilled the holes and slots such that he can fix the display on either side. Along the way, he discovered an interesting issue regarding the display orientation – check it out. The final result is a nice looking media centre that sits proudly on top of his audio rig.

Filed under: Raspberry Pi

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Retrotechtacular: Hallicrafters Goes To War

Retrotechtacular: Hallicrafters Goes To War

When the USA entered World War Two, they lacked a powerful mobile communications unit. To plug this gap they engaged Hallicrafters, prewar manufacturers of amateur radio transmitters and receivers, who adapted and ruggedized one of their existing products for the application.
The resulting transmitter was something of a success, with production running into many thousands of units. Hallicrafters were justifiably proud of it, so commissioned a short two-part film on its development which is the subject of this article.
The transmitter itself was a very high quality device for the era, but even with the film’s brief insight into operating back in the AM era the radio aspect is not what should capture your interest. Instead of the radio it is the in-depth tour of an electronics manufacturing plant in the war years that makes this film, from the development process of a military product from a civilian one through all the stages of production to the units finally being fitted to Chevrolet K-51 panel vans and shipped to the front. Chassis-based electronics requiring electric hoists to move from bench to bench are a world away from today’s surface-mount micro-circuitry.
So sit back and enjoy the film, both parts are below the break.

If your appetite has been whetted for World War II-era technology in glorious monochrome by this film, maybe we can help. There is this film on the post-war testing of V2 rockets in the Hackaday archive, this film on the jet engine, or how about this film on experiments with derailing trains?

Thanks [K8MHZ], via this QRZ.com thread.

Filed under: Retrotechtacular

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Two-Sided Laser Etching

Two-Sided Laser Etching

[Dan Royer] explains a simple method to engrave/etch on both sides of a material. This could be useful when you are trying to build enclosures or boxes which might need markings on both sides. There are two hurdles to overcome when doing this. The first is obviously registration. When you flip your job, you want it re-aligned at a known datum/reference point.

The other is your flip axis. If the object is too symmetric, it’s easy to make a mistake here, resulting in mirrored or rotated markings on the other side. Quite simply, [Dan]’s method consists of creating an additional cutting edge around your engraving/cutting job. This outline is such that it provides the required registration and helps flip the job along the desired axis.

You begin by taping down your work piece on the laser bed. Draw a symmetrical shape around the job you want to create in your Laser Cutter software of choice. The shape needs to have just one axis of symmetry – this rules out squares, rectangles or circles – all of which have multiple axes of symmetry. Adding a single small notch in any of these shapes does the trick. Engrave the back side. Then cut the “outside” outline. Lift the job out and flip it over. Engrave the front side. Cut the actual outline of your job and you’re done.

Obviously, doing all this requires some preparation in software. You need the back engrave layer, the front engrave layer, the job cut outline and the registration cut outline. Use color coded pen settings in a drawing to create these layers and the horizontal / vertical mirror or flip commands. These procedures aren’t groundbreaking, but they simplify and nearly automate a common procedure. If you have additional tricks for using laser cutters, chime in with your comments here.

Filed under: cnc hacks

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