Hackaday Prize Entry: Orchestral Invention Defies Convention

Like many of us, [Laurens] likes video game music and bending hardware to his will. Armed with a Printrbot, a couple of floppy drives, and some old HDDs, he built the Unconventional Instrument Orchestra. This 2015 Hackaday Prize contender takes any MIDI file and plays it on stepper and solenoid-based hardware through a Java program.

A while back, [Laurens] won a Fubarino in our contest by using a MIDI keyboard and an Arduino to control the Minecraft environment with Legend of Zelda: Ocarina of Time songs. The Unconventional Instrument Orchestra uses that Fubarino of victory to control the steppers of two floppy drives. He only needed three pins to control the drives—one to enable, one to set the head’s direction, and one to make it step once per pulse.

If ever you’ve been around a 3D printer, you know they make music as a natural side effect. The problem is getting the printer to obey the rests in a piece of music. In order to do this, [Laurens] used his software to control the printer, essentially withholding the next command until the appropriate time in the song.

The percussive elements of this orchestra are provided by a hard drive beating its head against the wall. Since it’s basically impossible to get an HDD to do this as designed (thankfully), [Laurens] replaced the control board with a single transistor to drive the coil that moves the head.

[Laurens] has made several videos of the orchestra in concert, which are a joy all their own. Most of the visual real estate of each video is taken up with a real-time visualization of the music produced by the software. There’s still plenty of room to show the orchestra itself, song-specific gameplay, and a textual commentary crawl in 16-segment displays. Check out the playlist we’ve embedded after the break.

The 2015 Hackaday Prize is sponsored by:

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LED Strip Notifies You Of The Light Show You’re Missing Outside

Unless you live way up in Canada, it’s not very likely that those gorgeous coronal mass ejections will collide with the atmosphere above your home. If they do, it’s a rare occurrence you wouldn’t want to miss. This is why [James] devised of a special alarm that would notify him when the Northern Lights may be visible in his neck of the woods. And what’s a better aurora alarm than a simulated aurora light show for your room?

[James] uses a Raspberry Pi to check data from Aurora Watch UK at Lancaster University for local activity. If the forecast reads that there may be some light above his home town in northern England, it triggers a NeoPixel LED strip to scroll through the color values of an actual aurora PNG image. This produces the same sporadic shifting of colors for a proximal ambient indoor lighting effect… though slightly less dramatic than the real thing. You can take a look at his Python script on github if you feel inspired.

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Lighting The Great Indoors With A Solar Security Light

Look at any list of things to do to make your house less attractive to the criminal element and you’ll likely find “add motion sensing lights” among the pro tips. But what if you don’t want to light up the night? What if you want to use a motion sensor to provide a little light for navigating inside a dark garage? And what if the fixture you’ve chosen is a solar fixture that won’t quite cooperate? If you’re like [r1ckatkinson], you do a teardown and hack the fixture to do your bidding.

[r1ckatkinson]’s fixture was an inexpensive Maplin solar unit with PIR motion sensing, with the solar panel able to be mounted remotely. This was perfect for the application, since the panel could go outside to power the unit, with the lamp and PIR sensor inside. Unfortunately, the solar cell is also the photosensor that tells the unit not to turn on during the day. Armed with scratch pad and pencil, [r1ckatkinson] traced the circuit and located the offending part – a pull-down resistor. A simple resistor-ectomy later and he’s got a solar-powered light working just the way he likes it.

A simple hack, but effective. Seeing off-the-shelf gear modified is always a treat. Of course there’s something to be said for the more home-brew approach to security lighting, too.

Wireless Power Transfer Using Capacitive Plates

It seems like wireless power transfer is all the rage these days. There’s wireless charging mats, special battery packs, heck, even some phones have it built in! And they all use inductive coils to transfer the power — but what if there was another way? Coils of copper wire aren’t always that easy to fit inside of a product…

As an experiment, [Josh Levine] decided to try making a proof of concept for capacitive power transfer.

He first demonstrates inductive power transfer using two coils of copper wire to power up an LED. The charging coil is supplied with 15V peak-to-peak at 1MHz which is a fairly typical value for inductive charging. He then shows us two glass plates with some tinfoil taped to it. Two LEDs bridge the gap alternating polarity — since the power is oscillating, so we need a path for electrons to flow in both directions. There is no connection through the glass, but when it is set on the charging plate, the LEDs light up. The charging plate is supplied with 30V peak-to-peak at 5MHz.

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Hacklet 56 – Brain Hacks

The brain is the most powerful – and least understood computer known to man. For these very reasons, working with the mind has long been an attraction for hackers, makers, and engineers. Everything from EEG to magnetic stimulus to actual implants have found their way into projects. This week’s Hacklet is about some of the best brain hacks on Hackaday.io!

teensy-bio[Paul Stoffregen], father of the Teensy, is hard at work on Biopotential Signal Library, his entry in the 2015 Hackaday Prize. [Paul] isn’t just hacking his own mind, he’s creating a library and reference design using the Teensy 3.1. This library will allow anyone to read electroencephalogram (EEG) signals without having to worry about line noise filtering, signal processing, and all the other details that make recording EEG signals hard. [Paul] is making this happen by having the Teensy’s cortex M4 processor perform interrupt driven acquisition and filtering in the background. This leaves the user’s Arduino sketch free to actually work with the data, rather than acquiring it. The initial hardware design will collect data from TI ADS129x chips, which are 24 bit ADCs with 4 or 8 simultaneous channels. [Paul] plans to add more chips to the library in the future.


bioxNext up is [Jae Choi] with Lucid Dream Communication Link. [Jae] hopes to create a link between the dream world and the real world. To do this, they are utilizing BioEXG, a device [Jae] designed to collect several types of biological signals. Data enters the system through several active probes. These probes use common pogo pins to make contact with the wearer’s skin. [Jae] says the active probes were able to read EEG signals even through their thick hair! Communication between dreams and the real world will be accomplished with eye movements. We haven’t heard from [Jae] in awhile – so we hope they aren’t caught in limbo!

bioloop[Qquuiinn] is working from a different angle to build bioloop, their entry in the 2015 Hackaday Prize. Rather than using EEG signals, [Qquuiinn] is going with Galvanic Skin Response (GSR). GSR is easy to measure compared to EEG signals. [Qquuiinn] is using an Arduino Pro Mini to perform all their signal acquisition and processing. This biofeedback signal has been used for decades by devices like polygraph “lie detector” machines. GSR values change as the sweat glands become active. It provides a window into a person’s psychological or physiological stress levels. [Qquuiinn] hopes bioloop will be useful both to individuals and to mental health professionals.

biomonitorFinally we have [Marcin Byczuk] with Biomonitor. Biomonitor can read both EEG and electrocardiogram (EKG) signals. Unlike the other projects on today’s Hacklet, Biomonitor is wireless. It uses a Bluetooth radio to transmit data to a nearby PC or smartphone. The main processor in Biomonitor is an 8 bit ATmega8L. Since the 8L isn’t up to a lot of signal processing, [Marcin] does much of his filtering the old fashioned way – in hardware. Carefully designed op-amp based active filters provide more than enough performance when measuring these types of signals. Biomonitor has already found it’s way into academia, being used in both the PalCom project, and brain-computer interface research.

If you want more brain hacking goodness, check out our brain hacking project list! Did I miss your project? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Send In The Drones: Putting Wheels And Wings On The Internet Of Things

Imagine you’re a farmer trying to grow a crop under drought conditions. Up-to-the-minute data on soil moisture can help you to decide where and when to irrigate, which directly affects your crop yield and your bottom line. More sensors would mean more data and a better spatial picture of conditions, but the cost of wired soil sensors would be crippling. Wireless sensors that tap into GSM or some sort of mesh network would be better, but each sensor would still need power, and maintenance costs would quickly mount. But what if you could deploy a vast number of cheap RFID-linked sensors in your fields? And what if an autonomous vehicle could be tasked with the job of polling the sensors and reporting the data? That’s one scenario imagined in a recent scholarly paper about a mobile Internet of Things (PDF link).


In the paper, authors [Jennifer Wang], [Erik Schluntz], [Brian Otis], and [Travis Deyle] put a commercially available quadcopter and RC car to the hack. Both platforms were fitted with telemetry radios, GPS, and an off-the-shelf RFID tag reader and antenna. For their sensor array, they selected passive UHF RFID tags coupled to a number of different sensors, including a resistance sensor used to measure soil moisture. A ground-control system was developed that allowed both the quad and the car to maneuver to waypoints under GPS guidance to poll sensors and report back.

Beyond agriculture, the possibilities for an IoT based on cheap sensors and autonomous vehicles to poll them are limitless. The authors rightly point out the challenges of building out a commercial system based on these principles, but by starting with COTS components and striving to keep installed costs to a minimum, we think they’ve done a great proof of concept here.

Fooling Google Search Console With Tricky PHP

When [Steve] received a notice from Google that a new owner had been added to his Google Search Console account, he knew something was wrong. He hadn’t added anyone to his account. At first he thought it might be a clever phishing tactic. Maybe the email was trying to get him to click a malicious link. Upon further investigation, he discovered that it was legitimate. Some strange email address had been added to his account. How did this happen?

When you want to add a website to Google’s services, they require that you prove that you own the actual website as a security precaution. One method to provide proof is by uploading or creating an HTML file to your website with some specific text inside. In this case, the file needed to be called “google1a74e5bf969ded17.html” and it needed to contain the string “google-site-verification: googlea174e5bf969ded17.html”.

[Steve] logged into his web server and looked in the website directory but he couldn’t find the verification file. Out of curiosity, he tried visiting the web page anyways and was surprised to find that it worked. After some experimentation, [Steve] learned that if he tried to load any web page that looked like “googleNNNNNNN.html”, he would be presented with the corresponding verification code of “google-site-verification: googleNNNNNNNN.html”. Something was automatically generating these pages.

After further investigation, [Steve] found that some malicious PHP code had been added to his website’s index.php page. Unfortunately the code was obfuscated, so he couldn’t determine exactly what was happening. After removing the new code from the index.php file, [Steve] was able to remove the hacker’s email address from [Steve’s] Google account.

This is a very interesting hack, because not only did it allow this one hacker to add himself to [Steve’s] Google account, but it would also have allowed anyone else to do the same thing. This is because each new hacker would have been able to fool Google’s servers into thinking that they had uploaded the verification file thanks to the malicious PHP code. It makes us think that perhaps Google’s verification system should use a separate randomized string inside of the verification file. Perhaps one that can’t be guessed or calculated based on known variables such as the file name.