Designed by Montreal studio Daily tous les jours, Mesa Musical Shadows is a public installation which turns several blocks of pavement in Arizona’s Mesa Arts Center into a super-sized dance pad that reacts to your moving shadow with the sounds of singing.

Shadows cast on different tiles trigger different voices, all while singing in harmony. Length of shadow is dependent upon the season, the time of day and the weather; meaning, a visitor may never quite cast the same shadow twice. The sounds themselves also change with the angle of the sun, which makes interacting with the installation a dynamic experience in the morning, midday, evening, and in the middle of the night. As the day turns into night, the tracks shift from upbeat, Pitch Perfect-like acapella to creepier, ominous tones.

Though all the audio originates with recordings of the human voice, a large variety of sounds and moods are created throughout the day. The sounds triggered in the morning are peaceful and ethereal: sustained choral tones that follow your long shadow, singing you into your day. Later, when the sun is hot overhead, and shadows are shorter; the sounds are chopped and frenetic, creating a rhythmic, energetic soundtrack. As the shadows become long again toward sunset, clusters of complementary, interlocking melodies are triggered. Finally, after dark, the sounds harken toward the natural landscape: Insect or bird-like vocal sounds evoking a nocturnal meadow are triggered by users navigating their way through the night.

The system itself consists of sensors that respond to changes in light, which prompt a range of melodic or percussive sounds emitted through speakers embedded in the colorful fabricated tiles. As Creative Applications details, Mesa Musical Shadows is controlled by a MaxMSP patch linking Arduino Mega boards via OSC.

The installation’s 47 sensors are run through six control nodes, comprised of an Arduino Mega, Ethernet shields, and custom connector shields – each of which is protected in a waterproof enclosure, placed underneath the tiling. Each sensor unit has a custom PCB with a light sensor on top and an LED on its bottom, for nighttime illumination and the more sensitive gear (computers, amplifiers, etc.) is all installed in the museum.

If this musical public display seems a bit familiar, that’s because you may recall Daily Tous Les Jours’ earlier project, 21 Swings, which used playground swings to form a giant collective instrument. Read more about the singing sidewalk here, and see it in action below!

Mike, CEO of the Useless Duck Company, continues to make us laugh with his hilarious Arduino innovations. Despite all the comical projects, which range from a fedora that tips itself to an automated toilet paper-dispensing machine, he may be onto something with one of his more recent contraptions: a door that locks itself whenever you’re shopping for gifts for your wife or significant other.

If you don’t want Google Chrome to save a record of what you visit and download, you can always browse the web in incognito mode However, what happens if your loved one bursts into the room and catches you in the act of making a purchase?

To solve this common problem, Mike has hooked his PC up to an Arduino Uno that’s connected to a servo-controlled lock. A self-written program then checks all of the browsers running on his computer, and if it finds one in incognito mode, it sends a signal to the Arduino to bolt the door.

[Dan Bowen] describes the construction of a backyard hydroponics set-up in an angry third person tirade. While his friends assume more nefarious, breaking, and bad purposes behind [Dan]’s interest in hydroponics; he’d just like some herbs to mix into the occasional pasta sauce.

Feel particularly inspired one day after work, he stopped by the local hardware store and hydroponics supply. He purchases some PVC piping, hoses, fittings, pumps, accessories, and most importantly, a deck box to hide all the ugly stuff from his wife.

The design is pretty neat. He has an open vertical spot that gets a lot of light on his fence. So he placed three lengths of PVC on a slant. This way the water flows quickly and aerates as it goes. The top of the pipes have holes cut in them to accept net baskets.

The deck box contains a practically industrial array of sensors and equipment. The standard procedure for small-scale hydroponics is just to throw the water out on your garden and replace the nutrient solution every week or so. The hacker’s solution is to make a rubbermaid tote bristle with more sensors than the ISS.

We hope his hydroponics set-up approaches Hanging Gardens of Babylon soon.

Taking great pictures means making them more vibrant enhancing saturation and contrast. Ynformatic has published some tips to help you do that by creating a DIY device to control a polarizer using an Arduino Pro Mini, an iPhone, and a screen from an auto-darkening welder’s mask.

A phototransistor located facing the iPhone’s flashlight LED is connected to both an external interrupt pin and an analog pin. Short pulses on the LED cause interrupts in the Arduino code which are used to synchronize the polarizer. Long pulses on the LED cause the Arduino to enter calibration mode. The time interval between syncrhonization pulses is continuously measured and divided into three equal parts. On receiving a synchronization pulse the voltage is set to 0V for one part, to the 45 degree voltage for one part and finally to 5V for one part. Voltage for the polarizer is supplied from an Arduino PWM output pin. To get a reasonably stable output the PWM frequency was increased to 32 kHz and smoothed with a second order RC filter. The liquid crystal display will be damaged by a constant DC voltage so a CMOS switch is used to alternate the polarity. A 2 kHz square wave generated from a free running Arduino timer is used to drive the switching.

An iPhone app written in Swift is responsible for the user interface and image processing.

Explore the schematic in the picture below, while the full source code for the Arduino and iPhone can be downloaded from here.

Have you ever wished your Arduino project could play tunes, or even just note-based sound effects? Connor Nishijima has, and that’s why over the last three years he has been hard at work developing Miduino–a free web service that enables Makers to automatically convert their MIDI music into ready-made sketches.

Unlike any built-in Arduino noisemaking functions such as tone(), Miduino’s output is polyphonic–meaning you can play up to six notes at once. Most recently, he has added two major updates to the service: percussion tracking and switch to software-based timing.

Now the only thing setting your Arduino apart from an NES is a proper triangle wave! While it’s not fully featured yet for the whole MIDI percussion spectrum, your basic snares, kicks and hi-hats will be joining the music!

Originally I collaborated with Len Shustek to tie his Playtune library into the service, but his library requires a hardware timer for each active note–which has its ups and downs.

With a hardware timer you’ll get extremely crisp sound every time, but an Arduino Uno can only play up to three notes at once and the original code didn’t know what to do with MIDI percussion channels.

Instead, Nishijima is polling for new notes and their expirations at about 22,050Hz using Timer 1 and generating different types of percussion with some RNG tricks. Admittedly it hasn’t been perfected yet, as some songs need the polling frequency turned down to avoid crashes. (Cut the Arduino some slack, it’s not supposed to be good at this!)

To demonstrate his latest upgrades, Nishijima plays Super Mario Bros. theme song with LEDs blinking to the iconic tunes. Although some would argue that this could be faked quite easily, the Maker has gone ahead and shared the code along with a couple other examples for any doubters–these include Van Halen’s “Eruption” and Mozart’s “Rondo Alla Turca.”

When it comes to telling time, Makers like to go beyond simply reading moving hands or looking at a digital display. In Imgur user Grahamvinyl’s case, that’s a slick word clock comprised of a walnut veneer, clear epoxy, LEDs, letters, and Arduino.

Grahamvinyl cut the clock from the back of an acoustic guitar and sides, and then strung together individually addressable RGB strips. A matrix of letters in Art Deco font spell out the time horizontally. Pieces of spraypainted 1/4-inch MDF act as dividers (so the color doesn’t bleed from one letter to the next), and a sheet of wax paper diffuses the light.

I haven’t seen another word clock designed the same way: clear epoxy holds the interior of the letters in place, so I didn’t need to use a stencil font.

The display changes every five minutes, and counts two minutes before and after the actual time (e.g. 10:13 and 10:17). Meanwhile, numbers that take longer to spell out such as “fifteen” are shown as “quarter past.”

The Arduino Uno-controlled clock also has a button on its side that allows it to show the numerical time—from far away, you’ll notice the illuminated letters actually create the shapes of numbers. The hours show up dimmer, the minutes brighter. Another push reveals the numerical date in the same fashion. You can even program it to flash a special message on your birthday.

Grahamvinyl notes that there are three buttons in total, each wired to an input on the Arduino. Right now, however, only the top one is functional. The idea is to eventually have the bottom two cycle through colors or set the time. Beyond that, the Maker hooked up a USB connection to the clock so that it would be easily programmable.

Interested in building your own word clock? Check out more images on Imgur, and find the code on GitHub.

Blood glucose monitors are pretty ubiquitous today. For most people with diabetes, these cheap and reliable sensors are their primary means of managing their blood sugar. But what is the enterprising diabetic hacker to do if he wakes up and realizes, with horror, that a primary aspect of his daily routine doesn’t involve an Arduino?

Rather than succumb to an Arduino-less reality, he can hopefully use the shield [M. Bindhammer] is working on to take his glucose measurement into his own hands.

[Bindhammer]’s initial work is based around the popular one-touch brand of strips. These are the cheapest, use very little blood, and the included needle is not as bad as it could be. His first challenge was just getting the connector for the strips. Naturally he could cannibalize a monitor from the pharmacy, but for someone making a shield that needs a supply line, this isn’t the best option. Surprisingly, the connectors used aren’t patented, so the companies are instead just more rigorous about who they sell them to. After a bit of work, he managed to find a source.

The next challenge is reverse engineering the actual algorithm used by the commercial sensor. It’s challenging. A simple mixture of water and glucose, for example, made the sensor throw an error. He’ll get it eventually, though, making this a great entry for the Hackaday Prize.

Word clocks are cool, but getting them to function correctly and look good is all about paying attention to the details. One look at this elegant walnut-veneered word clock shows what you can accomplish when you think a project through.

Most word clocks that use laser-cut characters like [grahamvinyl]’s effort suffer from the dreaded “stencil effect” – the font has bridges to support the islands in the middle of characters like “A” and “Q”. While that can be an aesthetic choice and work perfectly well, like in this word clock we featured a few months back, [grahamvinyl] was going for a different look. The clock’s book-matched walnut guitar back was covered in tape before being laser cut; the tape held the letters and islands in place. After painstakingly picking out the cutouts and tweaking the islands, he used clear epoxy resin to hold everything in place. The result is a fantastic Art Deco font and a clean, sleek-looking panel to sit on top of an MDF light box for the RGB LED strips.

The braided cloth cable adds a vintage look to the power cord, and [grahamvinyl] mentions some potential upgrades, like auto-dimming and color shifting. This is very much a work in progress, but even at this point we think it looks fabulous.

[via r/diy]

In order to resolve the problem of congestion at the entrance to their hackerspace, the minds at i3Detroit installed a motion-activated mechanical iris in their door’s porthole.

Grabbing the design online (which they are now hosting on their site here), the parts were laser cut out of wood, gold leaf was added for effect, and it was relatively easy to assemble. PIR sensors detect movement on both sides of the door and an FET resistor connected to an orange LED add some old-school science fiction flair. The iris is actuated by a 12V car window motor — which works just fine on the 5V power that it’s supplied with — and an Arduino filling in as a controller. Start and stop positioning required some limit switches that seem to do the trick.

Finally they laser cut acrylic plastic with the i3Detroit logo to complete the porthole modification. You can watch a video of the mechanical iris in all its glory here — but unfortunately it’s on Google+ (do people still use that??) so we can’t embed it in the post.

If you want to add this sleek idea to your home but lack a laser cutter (understandable), then you can still hack one out of some common household materials.

[via Evan’s Techie-Blog]

Unsatisfied with the present options for chess computers and preferring the feel of a real board and pieces, [Max Dobres] decided that his best option would be to build his own.

Light and dark wood veneer on 8mm MDF board created a board that was thin enough for adding LEDs to display moves and for the 10mm x 1mm neodymium magnets in the pieces to trip the reed switches under each space. The LEDs were wired in a matrix and connected to an Arduino Uno by a MAX7219 LED driver, while the reed switches were connected via a Centipede card. [Dobres] notes that you’ll want to test that the reed switches are positioned correctly — otherwise they might not detect the pieces!

A small LCD screen and four buttons also connect to the Arduino for configuring options a number of options, computer difficulty, and play styles, while a Raspberry Pi acts as the main computer.

The Raspberry Pi is using ChessBoard 2.05 as a rule set with consideration for special moves (such as en passant and castling). It’s currently unsupported but used with permission by its creator, John Eriksson. The chess program Stockfish is the actual engine; be sure to adjust the skill of the AI, as it defaults to an ELO of 2600! Unfortunately, it’s a rather finicky program, only running on Python 2.7. If that doesn’t appeal to you, [Dobres] has provided a nice list of other options to help you with your own build.

He has recently updated his design and done away with the need for the Arduino in the process which — especially if you use the Pi Zero — drops the cost of this project significantly. That should leave you with enough room in your budget to build a robot to make the moves for you!

[via Max Dobres]