Measuring The Time Is A Breeze With This Air Flow Clock

June 25, 2020 by Dan Maloney 15 Comments

If you’ve ever had surgery, and you’re over a certain age, chances are good you’re familiar with the dreaded incentive spirometer. It’s a little plastic device with one or more columns, each of which has a plastic ball in it. The idea is to blow into the thing to float the balls, to ensure that your lungs stay in good shape and reduce the chance of pneumonia. This unique air-powered clock reminds us a little of that device, without all the pain.

Like a spirometer, [Nir Tasher]’s clock has three calibrated tubes, each big enough to hold a foam ball loosely. At the bottom of each tube is a blower whose motor is under PWM control. A laser rangefinder sits below each ball and measures its height; the measurement is used by a PID loop to control the speed of each fan and thus the height of each ball. The video below shows that the balls are actually pretty steady, making the clock easy to read. It doesn’t, however, reveal what the clock sounds like; we’re going to go out on a limb here and guess that it’s pretty noisy. Still, we think it’s a fantastic way to keep time, and unique in the extreme.

[Nir]’s Air Flow clock is an early entry in the 2020 Hackaday Prize, the greatest hardware design contest on Earth. Everyone should enter something, or at least check out the cool things people are coming up with. It’s still early in the process, but there are so many neat projects already. What are you waiting for?

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DIY TV-B-Gone Is A-OK

June 25, 2020 by Kristina Panos 49 Comments

Where won’t they put a TV these days? We’ve even seen one creeping behind semi-transparent mirror film in the ladies’ room of a sports bar, though that one didn’t last long. Up until that moment, we had never wished so hard for a TV-B-Gone, especially one as small and powerful as this DIY version by [Shane].

The best thing about [Shane]’s DIY TV-B-Gone is the strength of signal, though the size is nothing to sneeze at. That’s a 10-watt array or IR LEDs out of a security camera, and you can see how much brighter it is than a single IR LED in the video after the break.

Packed inside this minty enclosure is an Arduino Nano, which holds all the TV power-off codes known to hackers and fires them off in quick succession. [Shane] salvaged a MOSFET from an electronic speed controller to drive that LED array, and there’s a voltage booster board to raise the 3.7V lithium battery to 5V. [Shane] hasn’t really had the chance to test this out in public what with the global pandemic and all, but was able to verify a working distance of 40 feet inside the house.

Don’t care for such a raw look? Hide your zapper inside a toy, like this sonic screwdriver version.

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Rotary Phone Takes You Around The World And Through Time – With Music

June 24, 2020 by Sven Gregori 5 Comments

Purposely choosing obsoleted technology combines all the joy of simpler times with the comfort of knowing you’re not actually stuck with outdated (and oftentimes inferior) technology. The rotary phone is a great example here, and while rarely anyone would want to go back to the lenghty, error-prone way of dialing a number on it on an everyday basis, it can definitely add a certain charm to a project. [Caroline Buttet] thought so as well, and turned her grandma’s old rotary phone into a time-traveling, globe-trotting web radio.

The main idea is fairly simple: a Raspberry Pi connects via browser to a web radio site that plays music throughout the decades from places all over the world. [Caroline]’s implementation has a few nice twists added though. First of all, the phone of course, which doesn’t only house the Raspberry Pi, but serves both as actual listening device via handset speaker, and as input device to select the decade with the rotary dial. For a headless setup, she wrote a Chromium extension that maps key events to virtual clicks on the corresponding DOM element of the web site — like the ones that change the decade — and a Python script that turns the rotary dial pulses into those key events.

However, the phone is only half the story here, and the country selection is just as fascinating — which involves an actual world map. An audio connector is attached to each selectable country and connected to an Arduino. If the matching jack is plugged into it, the Arduino informs the Raspberry Pi via serial line about the new selection, and the same Chromium extension then triggers the country change in the underlying web site. You can check all the code in the project’s GitHub repository, and watch a demo and brief explanation in the videos after the break.

Sure, listening radio through a telephone may not be the most convenient way — unless it’s the appropriate genre — but that clearly wasn’t the goal here anyway. It’s definitely an interesting concept, and we could easily see it transferred to some travel- or spy-themed escape room setting. And speaking of spying, if [Caroline]’s name sounds familiar to you, you may remember her virtual peephole from a few months back.

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Switch Tester Servo-Slaps Them ’til They Fail

June 23, 2020 by Kristina Panos 33 Comments

[James] is designing an open-source 3D printed keyboard switch, with the end goal of building a keyboard with as many printed parts as possible. Since keyswitches are meant to be pressed quite often, the DIY switches ought to be tested just as rigorously as their commercial counterparts are at the factory. Maybe even more so.

The broken spring after 13,000+ automated boings.

Rather than wear out his fingers with millions of actuations, [James] built a robot to test switches until they fail. All he has to do is plug a switch in, and the servo-driven finger slowly presses the slider down until the contacts close, which lights the LED.

The system waits 100ms for the contacts to stop any tiny vibrations before releasing the slider. That Arduino on the side tracks the contact and release points and sends them to the PC to be graphed. If the switch fails to actuate or release, the tester stops altogether.

We love that this auto-tester works just fine for commercial switches, too — the bit that holds the switch is separate and attaches with screws, so you could have one for every footprint variant. [James] recently did his first test of a printed switch and it survived an astonishing 13,907 presses before the printed coil spring snapped.

One could argue that this doubles as a servo tester. If you want a dedicated device for that, this one can test up to sixteen at a time.

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Score Big Against Boredom With Tabletop Bowling

June 21, 2020 by Kristina Panos 18 Comments

Bowling has been around since ancient Egypt and continues to entertain people of all ages, especially once they roll out the fog machine and hit the blacklights. But why pay all that money to don used shoes and drink watered-down beer? Just build a tabletop bowling alley in your spare time and you can bowl barefoot if you want.

Those glowing pins aren’t just for looks — the LEDs underneath them are part of the scoring system. Whenever a pin is knocked out of its countersunk hole, the LED underneath is exposed and shines its light on a corresponding light-dependent resistor positioned overhead. An Arduino Uno keeps track of of the frame, ball number, and score, and displays it on an LCD.

The lane is nearly six feet long, so this is more like medium-format bowling or maybe even skee-bowling. There are probably a number of things one could use for balls, but [lainealison] is using large ball bearings. Roll past the break to see it in action, but don’t go over the line!

Can’t keep your balls out of the gutter? Build a magic ball and make all wishful leaning more meaningful as you steer it down the lane with your body.

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Capture The Flag, Along With The Game Data

June 18, 2020 by Kristina Panos 7 Comments

With events of all sizes on hold and live sports mostly up in the air, it’s a great time to think of new ways to entertain ourselves within our local circles. Bonus points if the activity involves running around outside, and/or secretly doubles as a team-building exercise, like [KarelBousson]’s modernized version of Capture the Flag.

Much like the original, the point of this game is to capture the case and keep it for as long as possible before the other team steals it away. Here, the approach is much more scientific: the box knows exactly who has it and for how long, and the teams get points based on the time the case spends in any player’s possession.

Each player carries an RFID tag to distinguish them from each other. Inside the case is an Arduino Mega with a LoRa shield and a GPS unit. Whenever the game is afoot, the case communicates its position to an external Raspi running the game server.

If you haven’t met LoRa yet, check out this seven-part introductory tutorial.

Less Rock, More Roll: A MIDI Barrel Piano

June 18, 2020 by Sven Gregori 5 Comments

Strolling around a park, pedestrian zone, or tourist area in any bigger city is rarely complete without encountering the sound of a barrel organ — the perfect instrument if arm stamina and steady rotation speed are your kind of musical skills. Its less-encountered cousin, and predecessor of self-playing pianos, is the barrel piano, which follows the same playing principle: a hand-operated crank rotates a barrel, and either pins located on that barrel, or punched paper rolls encode the strings it should pluck in order to play its programmed song. [gabbapeople] thought optocouplers would be the perfect alternative here, and built a MIDI barrel piano with them.

Keeping the classic, hand-operated wheel-cranking, a 3D-printed gear mechanism rolls a paper sheet over a plexiglas fixture, but instead of having holes punched into it, [gabbapeople]’s piano has simple markings printed on them. Those markings are read by a set of Octoliner modules mounted next to each other, connected to an Arduino. The Octoliner itself has eight pairs of IR LEDs and phototransistors arranged in a row, and is normally used to build line-following robots, so reading note markings is certainly a clever alternative use for it.

Each LED/transistor pair represents a dedicated note, and to prevent false positives from neighboring lines, [gabbapeople] 3D printed little collars to isolate each of the pairs. Once the signals are read by the Arduino, they’re turned into MIDI messages to send via USB to a computer running any type of software synthesizer. And if your hands do get tired, you can also crank it with a power drill, as shown in the video after the break, along with a few playback demonstrations.

It’s always fun to see a modern twist added to old-school instruments, especially the ones that aren’t your typical MIDI controllers, like a harp, a full-scale church organ, or of course the magnificently named hurdy-gurdy. And for more of [gabbapeople]’s work, check out his split-flip weather display.

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