Wind Chimes And Dry Ice Make An Unusual Musical Instrument

September 19, 2017 by 29 Comments

When it comes to making music, there are really only a few ways to create the tones needed — pluck something, blow into something, or hit something. But where does that leave this dry-ice powered organ that recreates tunes with wind chimes and blocks of solid CO2?

It turns out this is firmly in the “hit something” camp, as [Leah Edwards] explains of her project. When the metal wind chime tubes come in contact with dry ice, the temperature difference sublimates the solid CO2. The puff of gas lifts the tube slightly, letting it fall back against the brick of dry ice and making a tone. The process is repeated rapidly, providing a vibrato effect while the tube is down. [Leah] used solenoids to lift the tubes and, having recently completed a stint at National Instruments, a bunch of NI gear to control them. The videos below show a few popular tunes and a little bit about the organ build. But what — no songs from Frozen?

We can easily imagine this same build using an Arduino or some other microcontroller. In fact, it puts us in mind of a recent reed organ MIDI project that has a few ideas to offer, like ways to quiet those solenoids.  Continue reading “Wind Chimes And Dry Ice Make An Unusual Musical Instrument” →

OptionsBleed – Apache Bleeds In Uncommon Configuration

September 19, 2017 by 8 Comments

[Hanno Böck] recently uncovered a vulnerability in Apache webserver, affecting Apache HTTP Server 2.2.x through 2.2.34 and 2.4.x through 2.4.27. This bug only affects Apache servers with a certain configuration in .htaccess file. Dubbed Optionsbleed, this vulnerability is a use after free error in Apache HTTP that causes a corrupted Allow header to be replied by the webserver in response to HTTP OPTIONS requests. This can leak pieces of arbitrary memory from the server process that may contain sensitive information. The memory pieces change after multiple requests, so for a vulnerable host an arbitrary number of memory chunks can be leaked.

Unlike the famous Heartbleed bug in the past, Optionsbleed leaks only small chunks of memory and more importantly only affects a small number of hosts by default. Nevertheless, shared hosting environments that allow for .htaccess file changes can be quite sensitive to it, as a rogue .htaccess file from one user can potentially bleed info for the whole server. Scanning the Alexa Top 1 Million revealed 466 hosts with corrupted Allow headers, so it seems the impact is not huge so far.

The bug appears if a webmaster tries to use the “Limit” directive with an invalid HTTP method. We decided to test this behaviour with a simple .htaccess file like this:

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Hackaday Prize Entry: The $50 Raspberry Pi Smartphone

September 19, 2017 by 69 Comments

The Hackaday Prize is a challenge to create hardware, and the ZeroPhone is quite possibly the most popular project entered in the Hackaday Prize. What is it? It’s a mobile phone built around the Raspberry Pi Zero that can be assembled for about $50 in parts. Already, it’s a finalist in the Hackaday Prize best product competition, a finalist for the grand prize of $50,000, and one of the most popular projects on Hackaday.io of all time.

We took a look at the ZeroPhone early this year, and while there have been significant advances in this project, the philosophy is still pretty much the same. This is a mobile phone with a numeric keypad and a 128 x 64 pixel OLED display — basically the same user interface as a Nokia brick. The brain of the phone is a Raspberry Pi Zero wrapped in a PCB sandwich, with options for WiFi, Bluetooth, HDMI and audio outputs, a USB port, battery charging, and a ton of GPIOs that include ISM band radios, infrared receivers and transmitters, more flash storage, and anything else you can imagine. Basically, we’re looking at one of those modular, reconfigurable smartphone ideas, using a Raspberry Pi as the brains. Tech journos should be creaming themselves over this. We’re looking forward to [Arsenijs]’ cover story in Wired.

As with any Open Source / DIY cell phone, the big question surrounding the ZeroPhone is the cellular radio. 2G radios are cheap and plentiful, but the infrastructure is either coming down shortly, or already is down. A 3G radio is a must for a minimum viable product, and [Arsenijs] says there are provisions for replacing the 2G radio with a 3G module. Of course, 3G modules aren’t as capital-‘O’-Open as their technological predecessors, but that’s a discussion for another time.

Already the ZeroPhone is a huge success. There’s an actual team working on this project, the ZeroPhone subreddit is bigger than the Hackaday subreddit, there are newsletters, a wiki, and there will be a crowdfunding campaign ‘shortly’. This is one to look out for, and a very worthy project in the running for the 2017 Hackaday Prize.

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There Is No Such Thing As An Invalid Unit

September 19, 2017 by 356 Comments

The Mars Climate Orbiter was a spacecraft launched in the closing years of the 1990s, whose job was to have been to study the Martian atmosphere and serve as a communications relay point for a series of other surface missions. It is famous not for its mission achieving these goals, but for the manner of its premature destruction as its orbital insertion brought it too close to the planet’s atmosphere and destroyed it.

The ill-fated Mars Climate Orbiter craft. NASA [Public domain].
The ill-fated Mars Climate Orbiter craft. NASA [Public domain].
The cause of the spacecraft entering the atmosphere rather than orbiting the planet was found in a subsequent investigation to be a very simple one. Simplifying matters to an extent, a private contractor supplied a subsystem which delivered a reading whose units were in the imperial system, to another subsystem expecting units in the SI, or metric system. The resulting huge discrepancy caused the craft to steer towards the surface of the planet rather than the intended orbit, and caused the mission to come to a premature end. Billions of dollars lost, substantially red faces among the engineers responsible.

This unit cock-up gave metric-using engineers the world over a brief chance to feel smug, as well as if they were being honest a chance to reflect on their good fortune at it not having happened on their watch. We will all at some time or another have made an error with respect to our unit calculations, even though in most cases it’s more likely to have involved a simple loss of a factor of ten, and not with respect to a billion dollar piece of space hardware.

But it also touches on one of those fundamental divides in the world between the metric and imperial systems. It’s a divide that brings together threads of age politics, geography, nationalism, and personal choice, and though it may be somewhere angels fear to tread (we’ve seen it get quite heated before to the tune of 885+ comments), it provides a fascinating subject for anyone with an interest in engineering culture.

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Hybrid Technique Breaks Backscatter Distance Barrier

September 19, 2017 by 31 Comments

Low cost, long range, or low power — when it comes to wireless connectivity, historically you’ve only been able to pick two. But a group at the University of Washington appears to have made a breakthrough in backscatter communications that allows reliable data transfer over 2.8 kilometers using only microwatts, and for pennies apiece.

For those unfamiliar with backscatter, it’s a very cool technology that modulates data onto RF energy incident from some local source, like an FM broadcast station or nearby WiFi router. Since the backscatter device doesn’t need to power local oscillators or other hungry components, it has negligible power requirements. Traditionally, though, that has given backscatter devices a range of a few hundred meters at most. The UW team, led by [Shyamnath Gollokota], describe a new backscatter technique (PDF link) that blows away previous records. By combining the spread-spectrum modulation of LoRa with the switched attenuation of incident RF energy that forms the basis for backscatter, the UW team was able to cover 2800 meters for under 10 microwatts. What’s more, with printable batteries or cheap button cells, the backscatter tags can be made for as little as 10 cents a piece. The possibilities for cheap agricultural sensors, ultracompact and low power wearable sensors, or even just deploy-and-forget IoT devices are endless.

We’ve covered backscatter before, both for agricultural uses and for pirate broadcasting stations. Backscatter also has also seen more cloak and dagger duty.

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In-Band Signaling: Quindar Tones

September 19, 2017 by 29 Comments

So far in this brief series on in-band signaling, we looked at two of the common methods of providing control signals along with the main content of a transmission: DTMF for Touch-Tone dialing, and coded-squelch systems for two-way radio. For this installment, we’ll look at something that far fewer people have ever used, but almost everyone has heard: Quindar tones.

Continue reading “In-Band Signaling: Quindar Tones” →

London Calling: The Hackaday UK Unconference Roundup

September 19, 2017 by 22 Comments

A trip to London, for provincial Brits, is something of an undertaking from which you invariably emerge tired and slightly grimy following your encounter with the cramped mobile sauna of the Central Line, its meandering international sightseers, and stampede of besuited commuters heading for the City. Often your fatigue after such an expedition will be that following the completion of a Herculean labour, but just sometimes it will instead be the contented tiredness of a fulfilling and busy time well spent.

Such will be the state of the happy band of the Hackaday community who made it to London this weekend for our UK unconference held in association with our sponsor, DesignSpark. A Friday night bring-a-hack social in a comfortable Bloomsbury pub, followed by Saturday in an auditorium next to one of the former Surrey Commercial Docks for a day of back-to-back seven-minute talks laying out the varied and interesting work our readers are involved in.

Continue reading “London Calling: The Hackaday UK Unconference Roundup” →