A Bluetooth Upgrade For An Unusual Set Of Headphones

October 30, 2018 by 11 Comments

We will have all picked up something from a junk pile or swap meet in our time that caught our eye not because we needed it but because it looked cool. [Quinn Dunki] did just that with an irresistible set of 1980s air traffic control headphones. What did she do with them? Turn them into a set of Bluetooth headphones of course!

The ‘phones in question are particularly interesting, as they turned out upon inspection to be a two-way radio in disguise. Cracking them open revealed a radio board and a logic board, and what makes them particularly interesting to this Hackaday scribe’s eye is their choice of frequency. She finds a crystal with a VHF airband frequency multiplier and concludes that they must operate there, but a look at the photos reveals all the ingredients of a classic AM or low HF receiver. There is a ferrite rod antenna and a variable capacitor, if we didn’t know that these were very high-end professional ‘phones we’d almost suspect they were a novelty AM radio from Radio Shack. If any readers can shed any light on the frequency and purpose of this device, we’re all ears.

The conversion involved a Sparkfun Bluetooth module breakout board paired with a little audio power amplifier. The original drivers were high-impedance and one of them had died, so she replaced them with a modern pair of identical size. The control buttons were mounted in the headphone’s external housing, after a wrong turn into attempting to create a custom enclosure. The result is a rather novel but high-quality set of ‘phones, and one we rather wish we’d found ourselves.

Kepler Closes Eyes After A Decade Of Discovery

October 30, 2018 by 16 Comments

Since its launch in March 2009, the Kepler Space Telescope has provided us with an incredible amount of data about exoplanets within our galaxy, proving these worlds are more varied and numerous than we could ever have imagined. Before its launch we simply didn’t know how common planets such as ours were, but today we know the Milky Way contains billions of them. Some of these worlds are so hot they have seas of molten rock, others experience two sunsets a day as they orbit a pair of stars. Perhaps most importantly, thousands of the planets found by Kepler are much like our own: potentially playing host to life as we know it.

Kepler lived a fruitful life by any metric, but it hasn’t been an easy one. Too far into deep space for us to repair it as we did Hubble, hardware failures aboard the observatory nearly brought the program to a halt in 2013. When NASA announced the spacecraft was beyond hope of repair, most assumed the mission would end. Even by that point, Kepler was an unqualified success and had provided us with enough data to keep astronomers busy for years. But an ingenious fix was devised, allowing it to continue collecting data even in its reduced capacity.

Leaning into the solar wind, Kepler was able to use the pressure of sunlight striking its solar panels to steady itself. Kepler’s “eyesight” was never quite the same after the failure of its reaction wheels, and it consumed more propellant than originally intended to maintain this careful balancing act, but the science continued. The mission that had already answered many of our questions about our place in the galaxy would push ahead in spite of a failure which should have left it dead in space.

As Kepler rapidly burned through its supply of propellant, it became clear the mission was on borrowed time. It was a necessary evil, as the alternative was leaving the craft tumbling through space, but mission planners understood that the fix they implemented had put an expiration date on Kepler. Revised calculations could provide an estimate as to when the vehicle would finally run its tanks dry and lose attitude control, but not a definitive date.

For the last several months NASA has known the day was approaching, but they decided to keep collecting data until the vehicle’s thrusters sputtered and failed. So today’s announcement that Kepler has at long last lost the ability to orient itself came as no surprise. Kepler has observed its last alien sunset, but the search for planets, and indeed life, in our corner of the galaxy doesn’t end today.

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Wavetable General MIDI For Everyone

October 30, 2018 by 13 Comments

There are only so many ways to generate music with a computer, and by far the most popular method is MIDI. It’s been around for thirty-five years, and you don’t get to be a decades-old standard for no reason. That said, turning MIDI into audio is a pain, but this project in the Musical Instrument Challenge for the Hackaday Prize makes it easy. It’s a Fluxamasynth Module that turns MIDI into something you can hear.

The key to this build is a single chip that takes MIDI data in and spits out audio, according to the 128 general MIDI sounds. This might not sound like much, but if you’ve ever tried to turn MIDI into sound, you’ll find your options are limited. There is exactly one chip that can do this and is easily obtainable: the SAM2695 from Dream Sound Synthesis. This chip was originally designed for cheap toy keyboards, but if you have a chip, you can do anything with it.

The Fluxamasynth Modules are inspired by the original Fluxamasynth, an Arduino shield that is basically a breakout board for the SAM chip. There’s a MIDI in, and an 1/8″ jack for output, and not much else. The Fluxamasynth Modules extend the capability by adding more support, including stereo output, reverb, chorus, flange, and delay effects, and digs down deep into the configurable parameters for tuning.

The hardware is basically an audio appliance for the Arduino, Raspberry Pi, and the ESP32, and allows for generative music through code. You can see an example of this project in the video below.

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Oliver Heaviside: Rags To Recognition, To Madness

October 30, 2018 by 45 Comments

Like any complex topic, electromagnetic theory has its own vocabulary. When speaking about dielectrics we may refer to their permittivity, and discussions on magnetic circuits might find terms like reluctance and inductance bandied about. At a more practical level, a ham radio operator might discuss the impedance of the coaxial cable used to send signals to an antenna that will then be bounced off the ionosphere for long-range communications.

It’s everyday stuff to most of us, but none of this vocabulary would exist if it hadn’t been for Oliver Heaviside, the brilliant but challenging self-taught British electrical engineer and researcher. He coined all these terms and many more in his life-long quest to understand the mysteries of the electromagnetic world, and gave us much of the theoretical basis for telecommunications.

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Want To Learn Ethernet? Write Your Own Darn AVR Bootloader!

October 30, 2018 by 25 Comments

There’s a school of thought that says that to fully understand something, you need to build it yourself. OK, we’re not sure it’s really a school of thought, but that describes a heck of a lot of projects around these parts.

[Tim] aka [mitxela] wrote kiloboot partly because he wanted an Ethernet-capable Trivial File Transfer Protocol (TFTP) bootloader for an ATMega-powered project, and partly because he wanted to understand the Internet. See, if you’re writing a bootloader, you’ve got a limited amount of space and no device drivers or libraries of any kind to fall back on, so you’re going to learn your topic of choice the hard way.

[Tim]’s writeup of the odyssey of cramming so much into 1,000 bytes of code is fantastic. While explaining the Internet takes significantly more space than the Ethernet-capable bootloader itself, we’d wager that you’ll enjoy the compressed overview of UDP, IP, TFTP, and AVR bootloader wizardry as much as we did. And yes, at the end of the day, you’ve also got an Internet-flashable Arduino, which is just what the doctor ordered if you’re building a simple wired IoT device and you get tired of running down to the basement to upload new firmware.

Oh, and in case you hadn’t noticed, cramming an Ethernet bootloader into 1 kB is amazing.

Speaking of bootloaders, if you’re building an I2C slave device out of an ATtiny85¸ you’ll want to check out this bootloader that runs on the tiny chip.

Relativity Space’s Quest To 3D Print Entire Rockets

October 30, 2018 by 27 Comments

While the jury is still out on 3D printing for the consumer market, there’s little question that it’s becoming a major part of next generation manufacturing. While we often think of 3D printing as a way to create highly customized one-off objects, that’s a conclusion largely based on how we as individuals use the technology. When you’re building something as complex as a rocket engine, the true advantage of 3D printing is the ability to not only rapidly iterate your design, but to produce objects with internal geometries that would be difficult if not impossible to create with traditional tooling.

SpaceX’s SuperDraco 3D Printed Engine

So it’s no wonder that key “New Space” players like SpaceX and Blue Origin make use of 3D printed components in their vehicles. Even NASA has been dipping their proverbial toe in the additive manufacturing waters, testing printed parts for the Space Launch System’s RS-25 engine. It would be safe to say that from this point forward, most of our exploits off of the planet’s surface will involve additive manufacturing in some capacity.

But one of the latest players to enter the commercial spaceflight industry, Relativity Space, thinks we can take the concept even farther. Not content to just 3D print rocket components, founders Tim Ellis and Jordan Noone believe the entire rocket can be printed. Minus electrical components and a few parts which operate in extremely high stress environments such as inside the pump turbines, Relativity Space claims up to 95% of their rocket could eventually be produced with additive manufacturing.

If you think 3D printing a rocket sounds implausible, you aren’t alone. It’s a bold claim, so far the aerospace industry has only managed to print relatively small rocket engines; so printing an entire vehicle would be an exceptionally large leap in capability. But with talent pulled from major aerospace players, a recently inked deal for a 20 year lease on a test site at NASA’s Stennis Space Center, and access to the world’s largest metal 3D printer, they’re certainly going all in on the idea. Let’s take a look at what they’ve got planned.

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