Let’s face it, we’re all a bit obsessed with tools. Whether it’s an oscilloscope or a screwdriver, having just the right tool can be the difference between loving what you are doing, or dreading it. But oddly enough, not much is talked about tool organization. We tend to think that how you organize your tools is just as import as the tools themselves.
[Adam Savage] of Mythbusters fame might just be the king of tool organization. In this thread on the Replica Props Forum, [Adam] shares the design and construction of two sets of mobile tool boxes he built while working at Industrial Light and Magic. The idea is simple: First Order Retrievability. That is, you should never have to move one tool to get to another. That in turn affords the fastest, most efficient way of working.
The evolution of this idea started with medical bags (the kind doctors would use, back in the day when doctors still made house calls), but as [Adam’s] tool collection grew, the leather was no match for 50 pounds of tools. So, he stepped up to two aluminum tool boxes. Adding wheels and a scissor lift allowed for a moveable set, at just the right height, that are always in reach. Perfect for model making, where being able to move to different parts of a model, and taking your tools with you is key. If you’re looking for a list of what’s inside [Adam]’s box of wonder, here you go.
What are some of your favorite ways of organizing your tools? What tips or tricks do you have? Post a picture or description in the comments. I’m sure we all could learn a bit from one another.
Filed under: tool hacks
About six months ago, we saw [tshen2]’s work on the DSP 01, a 2-input, 6-output DSP and crossover for extreme audiophiles, and we’re not talking about oxygen free rooms here. The DSP 01 turns a USB audio output into six outputs that will give you perfectly flat eq across bass, mids, and highs, integrates with a 6x100W amplifier, and compensates for room noise. There was a huge update to the project recently and [tshen] is more than happy to share the details
Getting to this phase of the project hasn’t been without its problems. To get the DSP communicating to a computer through a USB port, [tshen2] found a potential solution in the CP2114 USB to I2S Bridge. This device should function as a USB audio sink, translating digital audio into something the DSP understands. This chip did not work in [tshen]’s design. The CP2114 simply does I2S wrong; the I2S spec says the clock must be continuous. This chip implements I2S with a SPI, firmware, and a few other things, making it incompatible with to-spec I2S.
While there was some problems with getting audio in to the device, the core of the device has remained unchanged. [tshen2] is still using the Analog Devices DSP, with the interesting SigmaStudio being used to compensate for the frequency response of the room. This real, legit, science-based audiophile territory here, and an impressive development for a field that – sometimes understandably – doesn’t get the respect it deserves.
Filed under: digital audio hacks
[Nathan] is a mobile application developer. He was recently debugging one of his new applications when he stumbled into an interesting security vulnerability while running a program called Charles. Charles is a web proxy that allows you to monitor and analyze the web traffic between your computer and the Internet. The program essentially acts as a man in the middle, allowing you to view all of the request and response data and usually giving you the ability to manipulate it.
While debugging his app, [Nathan] realized he was going to need a ride soon. After opening up the Uber app, he it occurred to him that he was still inspecting this traffic. He decided to poke around and see if he could find anything interesting. Communication from the Uber app to the Uber data center is done via HTTPS. This means that it’s encrypted to protect your information. However, if you are trying to inspect your own traffic you can use Charles to sign your own SSL certificate and decrypt all the information. That’s exactly what [Nathan] did. He doesn’t mention it in his blog post, but we have to wonder if the Uber app warned him of the invalid SSL certificate. If not, this could pose a privacy issue for other users if someone were to perform a man in the middle attack on an unsuspecting victim.
[Nathan] poked around the various requests until he saw something intriguing. There was one repeated request that is used by Uber to “receive and communicate rider location, driver availability, application configurations settings and more”. He noticed that within this request, there is a variable called “isAdmin” and it was set to false. [Nathan] used Charles to intercept this request and change the value to true. He wasn’t sure that it would do anything, but sure enough this unlocked some new features normally only accessible to Uber employees. We’re not exactly sure what these features are good for, but obviously they aren’t meant to be used by just anybody.
Filed under: security hacks
Even the most well designed crypto algorithms can be broken if someone is smart enough to connect an oscilloscope to a processor. Over the last 15 years or so, an entire domain of embedded security has cropped up around the techniques of power and side channel analysis. The tools are expensive and rare, but [Colin O’Flynn] and the ChipWhisperer are here to bring a new era of hardware security to the masses.
The ChipWhisperer was the second place winner of last year’s Hackaday Prize. It’s an interesting domain of security research, and something that was previously extremely expensive to study. If you’re looking for a general overview of what the ChipWhisperer does, you might want to check out when we bumped into [Colin] at DEFCON last year.
While the original goal of the ChipWhisperer was to bring the cost of the tools required for power and side channel analysis down to something a hackerspace or researcher could afford, this was still too expensive for a Kickstarter campaign. To that end, [Colin] designed the ChipWhisperer Lite, a cut-down version, but still something that does most of what the original could do.
There are two parts to the ChipWhisperer Lite – the main section contains a big microcontroller, a big FPGA, and a high gain, low noise amplifier. This is the core of the ChipWhisperer, and it’s where all the power analysis happens. The other part is a target board containing an XMega microcontroller. This is where you’ll run all your encryption algorithms, and where you’ll find out if they can be broken by power analysis. The main board and target board are held together by a break-away connection, so if you want to run a power analysis on another board, just snap the ChipWhisperer in half.
[Colin] is offering up a ChipWhisperer Lite for around $200 USD – far, far less than what these tools cost just a year ago. We’re looking forward to a successful campaign and all the neat findings people with this board will find.
Filed under: Crowd Funding, security hacks
[Helios Labs] recently published version two of their 3D printed fish feeder. The system is designed to feed their fish twice a day. The design consists of nine separate STL files and can be mounted to a planter hanging above a fish tank in an aquaponics system. It probably wouldn’t take much to modify the design to work with a regular fish tank, though.
The system is very simple. The unit is primarily a box, or hopper, that holds the fish food. Towards the bottom is a 3D printed auger. The auger is super glued to the gear of a servo. The 9g servo is small and comes with internal limiters that only allow it to rotate about 180 degrees. The servo must be opened up and the limiters must be removed in order to enable a full 360 degree rotation. The servo is controlled by an Arduino, which can be mounted directly to the 3D printed case. The auger is designed in such a way as to prevent the fish food from accidentally entering the electronics compartment.
You might think that this project would use a real-time clock chip, or possibly interface with a computer to keep the time. Instead, the code simply feeds the fish one time as soon as it’s plugged in. Then it uses the “delay” function in order to wait a set period of time before feeding the fish a second time. In the example code this is set to 28,800,000 milliseconds, or eight hours. After feeding the fish a second time, the delay function is called again in order to wait until the original starting time.
Filed under: 3d Printer hacks, Arduino Hacks
Oscilloscopes are one of the most often used tools of the engineer, hacker, or maker. Voltmeters can do a lot, but when you really need to get a good look at a signal, a good scope is invaluable. This week’s hacklet is triggered by the rising slope of some of the best Oscilloscope projects on Hackaday.io!
We start with [DainBramage’s] recent project Stretching the Limits of a Rigol DS-1102E Scope. The new Rigol ds1054z may be getting all the press lately, but the older DS-1102E (100 MHz) model is still a very capable scope. [DainBramage] broke out his vintage Singer CSM-1 service monitor to generate frequencies all the way up to 500 MHz. The Rigol did admirably well, detecting a sine wave all the way up to 500 MHz. This is in part due to the scope’s 1 gigasample-per-second sampling rate. Once things got beyond the specified limit of 100 MHz though, the signal began to attenuate. Not bad for pushing a low-end scope way beyond its limits!
Next up is [Bruce Land] with his PIC32 oscilloscope. Microcontroller scope projects are nothing new, but one that runs at nearly 1 MHz sampling rate while generating NTSC composite video is nothing to sneeze at. [Bruce] pulled this off by using Direct Memory Access (DMA) to move the data from the ADC to memory, and to get the video data from memory to the I/O pins used to generate video. The video itself is created by a resistor tree DAC. All you need to make black and white video is three resistors and two I/O pins. [Bruce] says the entire scope cost about $4.00 us in parts!
[Jacob Christ] mixed art and science with his chipKIT Oscilloscope Plotter. [Jacob] used a Microchip PIC32 based Fubarino to draw patterns on his scope. To do this the scope must be set to X-Y mode. [Jacob] paired his Fubarino with a MCP4902 Digital to Analog Converter (DAC). Using a dedicated DAC is a great way to do this. [Jacob’s] images are a testament to that, as they’re some of the cleanest “scope art” drawings we’ve seen. Much like [Bruce Land], [Jacob] used his project as the basis for a college class. In fact, the image to the left was created by one of his students!
Want more scope goodness? Check out our new Oscilloscope Projects List!Hackaday.io Update!
Hackaday.io is getting new features every day. Our dev team has just rolled out a new gallery view. Just click on a project’s featured image, or the “View Gallery” button, and you will be taken to a gallery view of every image used in the project – including log images. YouTube videos will render in the gallery as well. It’s a great way to view a timeline of progress for some of the projects on hackaday.io. For a great example of this, check out OpenMV’s gallery.
In other Hackaday.io news, check out the Caption CERN Contest! Every week we put up a new image from CERN’s archives. The Hackaday.io user who comes up with the funniest caption wins a T-Shirt from The Hackaday Store!
Looks like we’ve hit the end of the trace for this Hacklet. Same hack time, same hack channel, bringing you the best of Hackaday.io!
Filed under: Hackaday Columns
So you’ve finished your project. You’ve got a wonderful circuit, a beautiful PCB, and everything works perfectly. You’re done right? Well, maybe not. Sure, a bare PCB might be fine for a dev board, but what if you have a LCD to mount, a knob that needs turning, and buttons that need pressing. Yeah, that potentiometer hanging off the board by a few wires isn’t so pretty, is it? So it’s time for a case. Yuck. We all hate modifying cases.
[Electrodacus] came up with a clever solution in the form of stacking PCBs to form a case. In his project, he actually has the circuitry spread across 3 PCBs, and uses surface mount connectors to connect them in a stack. Along the edges are specifically shaped PCBs to complete the enclosure. This technique could be used with only one PCB containing all the circuitry, and the others acting as the case sides and top.
In this solar battery management project, the base layer has most of the power circuitry. This layer uses an aluminum metal core PCB for heat dissipation. The center layer is home for the micro controller and supporting components. And the top layer is the “front panel” with capacitive touch buttons and a cut out for a LCD. The top layer silk screen contains the logo, button markings, and the pin out of all the connectors.
If you hate drilling and filling cases (as much as we do), this technique might be right for your next project.
[via EEVBlog Forums]
Filed under: hardware
If you’ve ever lived in a building with manually controlled central heating, you’ll probably understand [Martin]’s motivation for this hack. These heating systems often have old fashioned valves to control the radiator. No Nest support, no thermostat, just a knob you turn.
To solve this problem, [Martin] built a Wi-Fi enabled thermostat. This impressive build brings together a custom PCB based on the ESP8266 Wi-Fi microcontroller and a mobile-friendly web UI based on the Open Thermostat Scheduler. The project’s web server is fully self-contained on the ESP8266.
To replace that manual value, [Martin] used a thermoelectric actuator from a Swiss company called HERZ. This is driven by a relay, which is controlled by the ESP8266 microcontroller. Based on the schedule and the measured temperature, the actuator lets fluid flow through the radiator and heat the room.
As a bonus, the device supports NTP for getting the time, MQTT for publishing real-time data, and ThingSpeak for logging and graphing historic data. The source code and design files are available under a Creative Commons license.
Filed under: home hacks
Here’s a project that you don’t want to bring into an airport, ship through the mail, or probably even remove from your home. [ProjectGeek] has built himself a simple kitchen timer masquerading as a bomb. The build is actually pretty simple, but the end result is something that would look at home in a Hollywood action flick.
The timer circuit is built from four simple components. An 8051 microcontroller board is used as the primary controller and timer. The code is available on GitHub. This board is attached to a another board containing four momentary push buttons. These are used to program the timer and to stop the buzzing. Another board containing four 7-segment displays is used to show the remaining time on the timer. A simple piezo buzzer is used to actually alert you when the timer has run out. All of these components are connected with colorful jumper wires.
The physical part of this build is made from easily available components. Old newspapers are rolled up to form the “explosive” sticks. These are then covered in plain brown paper ordinarily used to cover text books. The rolls are bundled together and fixed with electrical tape. The electronics can then be attached to the base with some hot glue or double-sided tape.
Filed under: Microcontrollers
Who eats tomatoes while they run in the first place? No one… and Japanese ketchup company, Kagome would like to change that.
Dole has been sponsoring the Japan Marathon for years, supplying runners with ready to eat bananas to gnosh on-the-go for a quick boost of nutrients. Part of their advertising campaign this year is a Wearable-edible Banana that runners can eat hands free. Out of good humor and a desire to one-up the absurdity level, Kagome worked with known Japanese group, Maywa Denki to create the Tomatan, a smiling contraption that mounts on a runner’s shoulders and delivers tomatoes from a hopper directly into their face… as a reminder that though Japan could be eating wearable bananas, they could just as easily eat mechanically dispensed tomatoes instead.
Why is this awesome? When we’re talking about silliness and commercialism in Japan, the aforementioned Maywa Denki seems to always surface like a nonsense wielding genie. If you haven’t heard the name, this company is actually the identity of an artist group. They have a reputation for inventing mechanical gizmos that are humorously ridiculous, and then marketing them as serious products part of the Maywa Denki brand. The sixteen-pound piggy-back tomato feeder meant to help improve a runner’s stamina is just one example of their many “nonsense machines”.
When we bring the things we create to market, they are usually presented to the world as products of some sort. Maywa Denki bends this common concept of the product to create an identity around their works of art. Because why not solve an imaginary problem that doesn’t really need a solution?
Makes you wonder what kind of obnoxious contraption you’d build to wear in a crowd, huh?:
Dole Japan’s Wearable Banana propaganda:
Filed under: misc hacks
There are robots that will vacuum your house, mow your lawn, and keep their unblinking electronic eyes on you at all times while hovering hundreds of feet in the air. How about a robot that plays a violin? That’s what [Seth Goldstein] built. He calls it a ‘kinetic sculpture’, but there more than enough electronics and mechatronics to keep even the most discerning tinkerer interested.
There are three main parts of [Seth]’s violin-playing kinetic sculpture. The first is a bow carriage that draws the bow across the strings using an electromagnet to press the bow against the strings. The individual strings are fingered with four rubber disks, and a tilting mechanism rotates the violin so the desired string is always underneath the bow and mechanical fingers.
As far as software goes, the Ro-Bow transforms MIDI files into robotic mechanization that make the violin sing. From what we can tell, it’s not quite as good as a human player; only one string at a time can be played. It is, however, great at what it does and is an amazing mechanical sculpture.
Filed under: robots hacks
[Seandavid010] recently purchased a 2004 Volvo. He really liked the car except for the fact that it was missing some more modern features. He didn’t come stock with any navigation system or Bluetooth capabilities. After adding Bluetooth functionality to the stock stereo himself, he realized he would need a secure location to place his iPhone. This would allow him to control the stereo or use the navigation functions with ease. He ended up building a custom iPhone mount in just a single afternoon.
The key to this project is that the Volvo has an empty pocket on the left side of the stereo. It’s an oddly shaped vertical pocket that doesn’t seem to have any real use. [Seandavid010] decided this would be the perfect place to mount his phone. The only problem was that he didn’t want to make any permanent changes to his car. This meant no drilling into the dash and no gluing.
[Seandavid010] started by lining the pocket with blue masking tape. He then added an additional lining of plastic wrap. All of this was to protect the dashboard from what was to come next. He filled about half of the pocket with epoxy putty. We’ve seen this stuff used before in a similar project. He left a small opening in the middle with a thick washer mounted perpendicular to the ground. The washer would provide a place for an off-the-shelf iPhone holder to mount onto. [Seandavid010] also placed a flat, wooden paint stirrer underneath the putty. This created a pocket that would allow him to route cables and adapters underneath this new mount.
After letting the epoxy putty cure for an hour, he removed the block from the pocket. The stick was then removed, and any gaps were filled in with putty. The whole block was trimmed and smooth down for a more streamlined look. Finally, it was painted over with some flat black spray paint to match the color of the dashboard. An aftermarket iPhone holder allows [Seandavid010] to mount his cell phone to this new bracket. The cell phone holder allows him to rotate the phone into portrait or landscape mode, and even is adjustable to accommodate different sized phones.
Filed under: car hacks
Back in the 70s, industrial control was done with either relays and ladder logic or new programmable logic controllers. These devices turned switches on and off, moved stuff around a factory, and kept the entire operation running smoothly. In the late 70s, Motorola came out with an Industrial Control Unit stuffed into a tiny chip. The chip – the MC14500 – fascinated [Nicola]. He finally got around to building an ICU out of this chip, and although this was the standard way of doing things 30 years ago, it’s still an interesting build.
[Nicola]’s ICU is extremely simple, just eight relays, eight inputs, the MC14500, a clock, and some ROM. After wiring up the circuit, [Nicola] wrote a compiler, although this chip is so simple manually writing opcodes to a ROM wouldn’t be out of the question.
To demonstrate his ICU, [Nicola] connected up an on/off switch, a start button, and a stop button. The outputs are a yellow, green, and red lamp. It’s a simple task for even a relay-based control scheme, but [Nicola]’s board does everything without a hitch.
If you’re looking for something a little more complex, we saw the MC14500 being used as an almost-CPU last year.
Filed under: classic hacks
Who doesn’t like Star Wars, LEDs, and music? [Stathack] was looking for a unique piece of art to put in his living room… so he decided to make his own Vader EQ.
The EQ is a massive 4′ x 5′ piece made from plywood and MDF. [Stathack] traced the familiar helmet onto it by using a projector to project the outline onto the surface. Not having access to an extra large CNC or laser, he then painstakingly used a jigsaw to cut out all the white pieces of the design — holy cow.
This process only took weeks and weeks of sanding, filling and sanding again due to the excellent precision of a jigsaw.
Once that was all done, he created the backing plate out of MDF to provide structural support and mounting locations for the LEDs. Bit of spray paint later and a simple circuit with the Arduino and it’s both done, and awesome.
Too bad he filmed the video vertically… sigh.
Need more Vader? How about your own Sous Vadar?
Filed under: Arduino Hacks, led hacks
It’s a wee bit cold in Finland right now. And while dog sledding is always an option (though mostly for tourists), one gentleman who goes by [Jibjorkl] on YouTube decided to try making his own motorized sleigh — and it’s freaking awesome.
Unfortunately our Finnish language skills aren’t exactly up to snuff so we’ll just have to describe the invention; perhaps one of our Finnish readers could add some insight if we miss anything?
It appears that [Jibjorkl] has taken a hub motor with a wheel from a standard e-bike and mounted on what looks like a store-bought sleigh. The wheel has something which looks kind of like duct tape wrapped around it to help give it extra traction in the snow. There are two lead-acid batteries sitting atop the motor assembly, but we can see an e-bike Li-on pack mounted on the side too (likely 48V 20+aH).
Regardless of how it works — it’ll take two passengers pretty damn fast through the snow. We want to build one asap.
Now which would you prefer? A motorized sled like this one (that you can sit on!), or a snow-scooter?
Filed under: transportation hacks
[CNLohr] has made a habit of using ATtiny microcontrollers for everything, and one of his most popular projects is using an ATTiny85 to generate NTSC video. With a $2 microcontroller and eight pins, [CNLohr] can put text and simple graphics on any TV. He’s back at it again, only this time the microcontroller isn’t plugged into the TV.
The ATtiny in this project is overclocked to 30MHz or so using the on-chip PLL. That, plus a few wires of sufficient length means this chip can generate and broadcast NTSC video.
[CNLohr] mentions that it should be possible to use this board to transmit closed captioning directly to a TV. If you’re looking for the simplest way to display text on a monitor with an AVR, there ‘ya go: a microcontroller and two wires. He’s unable to actually test this, as he lost the remote for his tiny TV from the turn of the millennium. Because there’s no way for [CNLohr] to enable closed captioning on his TV, he can’t build the obvious application for this circuit – a closed caption Twitter bot. That doesn’t mean you can’t.
Filed under: ATtiny Hacks, video hacks
The idea of a pirate box is pretty simple. All you need is a tiny Linux system with a WiFi adapter, a bit of storage space, and the software that will allow anyone to upload a few files to the server and an interface that will let anyone on the network download those files. In practice, though, a pirate box is a mess of wires and power adapters – not the pocketable device a WiFi file sharing box should be.
[Chris] came up with a much smaller file sharing beacon. It’s not based on a router; instead, [Chris]’ build uses an ez Share WiFi microSD adapter. It’s a device meant to push pics taken by a digital camera up to the Internet, but by configuring the software just so, up to five users can connect to the adapter and pull files down from a microSD card. The build only requires putting power to the correct pins. A LiPo battery and charge controller takes care of this problem.
There are a few shortcomings to this project – [Chris] doesn’t know how to upload files to the device. Maybe someone sufficiently clever can figure out how to make that work. Still, if you’re ever in a situation where you’d like to share some files with people in the same building, this is the device you need.
Thanks [Jake] for the tip.
Filed under: Network Hacks, wireless hacks
A few years ago, small and cheap WiFi modules burst onto the scene and with that the Spark was born. It’s a tiny dev board with a TI CC3000 WiFi module, capable of turning any device into an Internet-connected device. It’s only the very beginning of the Internet of Things, yes, but an important step in the right direction. Now, Spark is unshackling itself from WiFi networks with the Spark Electron, a dev kit that comes with a cellular radio and data plan.
If you’ve ever tried to build a high altitude balloon, a project that will be out of range of WiFi, or anything else where cellular data would be a godsend, you’ll quickly realize Verizon, AT&T, Sprint, and all the other carriers out there don’t necessarily care about your project. As far as we can tell, Spark is the first company to fix this gaping hole in what cellular can do by offering their own service – 20,000 messages for $3/month and no contracts. Officially, that’s 1MB of data spread over 20k messages that are about 50 bytes in length.
There are a few dozen companies and organizations working on the next generation of The Internet Of Things, but these require completely new silicon and spectrum allocations or base stations. Right now, there’s exactly one way of getting a Thing on the Internet without WiFi, and that’s with cellular data. We have to hand it to Spark for this one, and can’t wait to see the projects that will be possible due to a trickle of Internet everywhere.
Filed under: Cellphone Hacks, Crowd Funding
If you’ve never seen a double pendulum before, it’s basically just a pendulum with another pendulum attached to the end. You might not think that’s anything special, but these devices can exhibit extremely chaotic behavior if enough energy is put into the system. The result is often a display that draws attention. [David] wanted to build his own double pendulum display, but he wanted to make it drive itself. The result is a powered double pendulum.
There aren’t many build details here, but the device is simple enough that we can deduce how it works from the demonstration video. It’s broken into two main pieces; the frame and the pendulum. The frame appears to be made mostly from wood. The front plate is made of three layers sandwiched together. A slot is cut out of the middle to allow a rail to slide up and down linearly. The rail is designed in such a way that it fits between the outer layers of the front plate like a track.
The pendulum is attached to the linear rail. The rail moves up and down and puts energy into the pendulum. This causes the pendulum to actually move and generate the chaotic behavior. The rail slides up and down thanks to an electric motor mounted to the base. The mechanics work similar to a piston on a crankshaft. The motor looks as though it is mounted to a wooden bracket that was cut with precision on a laser cutter. The final product works well, though it is a bit noisy. We also wonder if the system would be even more fun to watch if the rotation of the motor had an element of randomness added to it. Or he could always attach a paint sprayer to the end.
Filed under: misc hacks
[Gr4yhound] has been rocking out on his recently completed synth guitar. The guitar was built mostly from scratch using an Arduino, some harvested drum pads, and some ribbon potentiometers. The video below shows that not only does it sound good, but [Gr4yhound] obviously knows how to play it.
The physical portion of the build consists of two main components. The body of the guitar is made from a chunk of pine that was routed out by [Gr4yhound’s] own home-made CNC. Three circles were routed out to make room for the harvested Yamaha drum pads, some wiring, and a joystick shield. The other main component is the guitar neck. This was actually a Squire Affinity Strat neck with the frets removed.
For the electronics, [Gr4yhound] has released a series of schematics on Imgur. Three SoftPot membrane potentiometers were added to the neck to simulate strings. This setup allows [Gr4yhound] to adjust the finger position after the note has already been started. This results in a sliding sound that you can’t easily emulate on a keyboard. The three drum pads act as touch sensors for each of the three strings. [Gr4yhound] is able to play each string simultaneously, forming harmonies.
The joystick shield allows [Gr4yhound] to add additional effects to the overall sound. In one of his demo videos you can see him using the joystick to add an effect. An Arduino Micro acts as the primary controller and transmits the musical notes as MIDI commands. [Gr4yhound] is using a commercial MIDI to USB converter in order to play the music on a computer. The converter also allows him to power the Arduino via USB, eliminating the need for batteries.
Filed under: Arduino Hacks, musical hacks