Greet the Sun with a 555 Flute

Here’s an interesting implementation of a classic: the 555 timer as astable multivibrator for the noble purpose of making weird music. [pratchel] calls this a Morgenflöte or morning flute, indicating that it is best played in the morning. It would certainly wake up everyone in the house.

Instead of using LDRs in straight-up Theremin mode and waving his hands about, [pratchel] mounted one in each of several cardboard tubes. One tube is small and has just a few holes; this is intended to be used as a flute. [pratchel] cautions against locating holes too close to the LDR, because it will overpower the others when left uncovered. A larger tube with more holes can be used as a kind of light-dependent slide whistle with another holey tube that fits inside. We were disappointed to find that the giant tube sitting by the amplifier hasn’t been made into a contrabass flute.

Continuing the theme of astability, [pratchel] went completely solderless and built the circuit on a breadboard. The LDR’s legs are kept separate by a piece of cardboard. This kind of project and construction is fairly kid and beginner-friendly. It would be a good one for getting your musically inclined friends and family members into electronics. Here’s a 555 player piano built by Hackaday’s own [Steven Dufresne] that might be a good second step. Check out [pratchel]’s performance after the break.

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Motorized Music Box Cranks Out Stairway to Heaven

[Bokononestly] found a lil’ music box that plays Stairway to Heaven and decided those were just the kinds of dulcet tones he’d like to wake up to every morning. To each his own; I once woke up to Blind Melon’s “No Rain” every day for about six months. [Bokononestly] is still in the middle of this alarm clock project right now. One day soon, it will use a *duino to keep track of the music box’s revolutions and limit the alarm sound to one cycle of the melody.

stairway-musicbox-alarm-clock[Bokononestly] decided to drive the crank of the music box with a geared DC motor from an electric screwdriver. After making some nice engineering drawings of the dimensions of both and mocking them up in CAD, he designed and printed a base plate to mount them on. A pair of custom pulleys mounted to the motor shaft and the crank arm transfer motion using the exact right rubber band for the job. You can’t discount the need for a big bag ‘o rubber bands.
In order to count the revolutions, he put a wire in the path of the metal music box crank and used the body of the box as a switch. Check out the build video after the break and watch him prove it with the continuity function of a multimeter. A clever function that should at some point be substituted out for a leaf switch.

We’ve covered a lot of cool clock builds over the years, including one or two that run Linux. And say what you will about Stairway; it’s better than waking up to repeated slaps in the face.

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Retrotechtacular: Examining Music in 1950’s Russia

If you had told 12-year-old me that one day I would be able to listen to pretty much any song I wanted to on demand and also pull up the lyrics as fast as I could type the artist’s name and part of the title into a text box, I would have a) really hoped you weren’t kidding and b) would have wanted to grow up even faster than I already did.

The availability of music today, especially in any place with first world Internet access is really kind of astounding. While the technology to make this possible has come about only recently, the freedom of music listening has been fairly wide open in the US. The closest we’ve come to governmental censorship is the parental advisory sticker, and those are just warnings. The only thing that really stands between kids’ ears and the music they want to listen to is parental awareness and/or consent.

However, the landscape of musical freedom and discovery has been quite different in other corners of the world, especially during the early years of rock ‘n roll. While American teens roller skated and sock-hopped to the new and feverish sounds of Little Richard and Elvis Presley, the kids in Soviet Russia were stuck in a kind of sonic isolation. Stalin’s government had a choke hold on the influx of culture and greatly restricted the music that went out over the airwaves. They viewed Western and other music as a threat, and considered the musicians to be enemies of the USSR.

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Raspberry Pis Sweeten a Library’s Bottom Line

Here’s a great real-world use case for the Pi—a small job for a small computer. [viking–] works in a public library. Like many public libraries, this one has catalog-only terminals that are separate from the computers you reserve to get your fix of cat videos and Bejeweled Blitz. The catalog computers needed to be upgraded, and [viking–] replaced them all with Raspis.

They’re all running Raspbian and boot directly into Chromium with a clean profile every time. The Pis are otherwise completely locked down and accessible only through SSH. A dedicated WiFi network and whitelisted web access help keep them secure. The Pis reboot after five minutes of inactivity which erases all login credentials and bookmarks.

These terminals are scattered throughout the library. Those closest to the front desk have their Pi in a VESA mount on the back of the monitor. The others are locked up in cabinets so they don’t get pinched by the patrons. Library budgets are lean enough already. [viking–] was able to get management sign-off for the project by building a single prototype to show the simplicity of the system and the projected cost savings. Thanks to a couple of cron jobs, the Pis shut the monitors down every night, saving hundreds of dollars per year.

Building a Sturdy Remote Control Mailbox

This DIY mailbox pretty much has it all. Not only is it waterproof and secure, it’s beautifully built and unlikely to arouse the suspicion of or induce fear in the mailman.

It’s made of 2mm thick sheet metal and features accents made of merri, a rather nice blood wood native to Western Australia. [George] of Make It Extreme built this mailbox primarily for remote control access, the idea being that each of his family members would have a key fob remote to open it. There’s an input panel under the lid in case someone loses or forgets their remote.

The setup is simple. That 12V solar panel under the address number is connected to a solar charge controller and charges a small battery. Pushing the A button on the key fob remote triggers the latch to slide over, unlocking the door. A push of the B button turns on an interior light for late-night mail collecting. The tube on the side is for leaflets and other postal miscellany. Now, the coolest feature: when mail passes through the slot, it lets [George] know by calling his cell phone. Check out the build/demo video after the break.

We’ve featured all kinds of mailboxen over the years. This wifi-enabled ‘box uses an Amazon Dash button and a Pi to play the AOL notification on the owner’s phone. The flag on this adorable mini mailbox goes up when there’s mail in the real one outside.

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Now You’re Printing with Water

How do you earn a place in a flower festival with a handful of Arduinos and a 3D printer? By building a water curtain that draws flowers. That’s exactly what Tecnoateneu Vilablareix, a hacking community in Spain did. They built this project specifically for Temps de Flors, a popular annual gathering in Girona, Spain. More than just a flower festival, the event opens gardens and courtyards of culturally importance to the general public that are closed the rest of the year.

A pile of nozzle fail.

The water curtain uses four Arduino Nanos to control the valves, which work in pairs to draw flowers, words, and patterns. A Mega provides a wifi connection  to receive commands. Over 16 continuous days worth of print time went into the 128 valves and 64 nozzles that make up the water curtain. It took the group around 24 iterations to get the valve design just right—they have to be able to shut off quickly.

There’s an eight-video playlist after the break and a special video that shows how much we love pandering. Most of the ones in the playlist are quite short and demonstrate the final version of the water curtain. Others show the valve testing. The last is a time-lapse of the group setting it up at the festival. If you’re in the area, the festival runs until May 15th.

Now that you’re in the mood for computer-controlled water shows, here is a fountain controlled with a RaspPi.

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This Billboard Kills Zika Mosquitoes

Once in a great while, effective advertising doesn’t require any human engagement at all. This billboard, designed and built by a pair of Brazilian ad agencies and set free under the Creative Commons license offers a reproducible solution for trapping Aedes Aegypti mosquitoes, the primary carrier of the Zika virus.

Click to embiggen.
Click to embiggen.

The design seems pretty simple, although the plans leave a bit of explanation to be desired. Inside the billboard are canisters of Lurex 3, a lactic acid-based mosquito attractant that is available pretty cheaply on Amazon. The lactic acid mimics the scent of human sweat and is released outward to distances up to 4km (2.5 miles) in a fine mist along with CO₂. Together, the Lurex and CO₂ act like a sweaty, mouth-breathing human beacon to lure mosquitoes into the billboard, where they become trapped and are doomed to die of dehydration.
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