Making Music By Probing Magnetite Crystals

Well, noises anyway. [Dmitry Morozov] and [Alexandra Gavrilova] present an interesting electronics-based art installation, which probes a large chunk of crystalline magnetite, using a pair of servo-mounted probes, ‘measuring’ the surface conductivity and generating some sound and visuals.

It appears to have only one degree of freedom per probe, so we’re not so sure all that much of the surface gets probed per run, but however it works it produces some interesting, almost random results. The premise is that the point-to-point surface resistivity is unpredictable due to the chaotically formed crystals all jumbled up, but somehow uses these measured data to generate some waveshapes vaguely reminiscent of the resistivity profile of the sample, the output of which is then fed into a sound synthesis application and pumped out of a speaker. It certainly looks fun.

From a constructional perspective, hardware is based around a LattePanda fed samples by an ADS1115 ADC, which presumably is also responsible for driving the LCD monitor and the sound system. An Arduino is also wedged in there perhaps for servo-driving duty, maybe also as part of the signal chain from the probes, but that is just a guess on our part. The software uses the VVVV (Visual Live-programming suite) and the Pure Data environment.

We haven’t seen magnetite used for this type of application before, we tend to see it as a source of Iron for DIY knifemaking, as a medium to help separate DNA or just to make nanoparticles, for erm, reasons.

$60 Robot Arm Is Compact

Thanks to 3D printing and inexpensive controllers, a robot arm doesn’t need to break the bank anymore. Case in point? [Build Some Stuff] did a good-looking compact arm with servos for under $60. The arm uses an interesting control mechanism, too.

Instead of the traditional joystick, the arm has a miniature arm with potentiometers at each joint instead of motors. By moving the model arm to different positions, the main arm will mimic your motions. It is similar to old control systems using a synchro (sometimes called a selsyn), but uses potentiometers and servo motors.

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A milled PCB next to a woman wearing a dress that includes it

Elegant Evening Dress Sports Servo-Actuated Flowers

There’s been plenty of research into “smart fabrics”, and we’ve seen several projects involving items of clothing with electronics integrated inside. These typically include sensors and simple actuators like LEDS, but there’s no reason you can’t integrate moving electromechanical systems as well. [Rehana Al-Soltane] did just that: she made an elegant evening dress with flowers that open and close on command.

It took [Rehana] a bit of experimentation to figure out a floral design that opens and closes smoothly without crumpling the fabric or requiring excessive force to actuate. She finally settled on a plastic sheet sandwiched between two layers of fabric, with pieces of fishing line attached that pull the edges inward. The lines are guided through a tube down the back of the dress, where a servo pulls or releases them.

The mechanical flower can be operated by touch — [Rehana] made one of the other flowers conductive by embedding copper tape between its petals and connected it to the capacitive touch sensor interface of an Atmel microcontroller. The micro is sitting on a custom PCB that’s worn on the hip, with wires going to the servo at the back. You can see how the system operates in the video embedded below.

The dress is [Rehana]’s final project for the famous “How To Make (almost) Anything” course at MIT, and required a wide variety of skills: the cable guide was 3D printed, the flower petals were laser cut, the PCB was milled, and the end product was sewn together. [Rehana] has a knack for making electronics-infused clothes and accessories, including the flexible PCB crown that she’s wearing in the image above. Continue reading “Elegant Evening Dress Sports Servo-Actuated Flowers”

3D-Printed Servo Motor Has 360 Degrees Of Rotation

Hobby servos are nifty and useful for a wide range of projects. There’s nothing stopping you from building your own servos though, and you can even give them nifty features like 360-degree rotation In fact, that’s exactly what [Aaed Musa] did!

The servo relies on 3D printed gears in a 3D printed housing. The design makes prodigious use of threaded inserts to hold everything together nice and tight. A DC motor is charged with driving the assembly, as with any regular servo motor. However, in the place of a potentiometer, this design instead uses an AS5600 magnetic rotary position sensor to read the servo’s angle, via a magnet mounted in the servo’s gear. An Arduino is used to determine the servo’s current position versus the desired position, and it turns the motor accordingly with a BTS7960 motor driver.

The result is a sizeable and capable servo with an easily-customizable output, given it’s all 3D printed. If you’d rather just mod some servos instead, we’ve covered some great work in that area, too. Video after the break.

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A Simon toy with a robot that slaps little hands against it

Silicone-Slapping Servos Solve Simon Says

Most modern computer games have a clearly-defined end, but many classics like Pac-man and Duck Hunt can go on indefinitely, limited only by technical constraints such as memory size. One would think that the classic electronic memory game Simon should fall into that category too, but with most humans struggling even to reach level 20 it’s hard to be sure. [Michael Schubart] was determined to find out if there was in fact an end to the latest incarnation of Simon and built a robot to help him in his quest.

The Simon Air, as the newest version is known, uses motion sensors to detect hand movements, enabling no-touch gameplay. [Michael] therefore made a system with servo-actuated silicone hands that slap the motion sensors. The tone sequence generated by the game is detected by light-dependent resistors that sense which of the segments lights up; a Raspberry Pi keeps track of the sequence and replays it by driving the servos.

We won’t spoil the ending, but [Michael] did find an answer to his question. An earlier version of the game was already examined with the help of an Arduino, although it apparently wasn’t fast enough to drive the game to its limits. If you think Simon can be improved you can always roll your own, whether from scratch or by hacking an existing toy.

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This Is The Future Of Waste Management

Many of us have been asking for some time now “where are our robot servants?” We were promised this dream life of leisure and luxury, but we’re still waiting. Modern life is a very wasteful one, with items delivered to our doors with the click of a mouse, but the disposal of the packaging is still a manual affair. Wouldn’t it be great to be able to summon a robot to take the rubbish to the recycling, ideally have it fetch a beer at the same time? [James Bruton] shares this dream, and with his extensive robotics skillset, came up with the perfect solution; behold the Binbot 9000. (Video, embedded below the break)

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Automatic Flag Waver Lets You Show Your Loyalty Without Getting Tired

A flag is a great tool to show your loyalty to a country, a sports team or even a philosophical movement. But there’s not so much you can actually do with a flag: you can either hang it somewhere, or wave it around to attact others to your cause. [Mellow] found that waving quickly becomes tiresome, and decided to design a machine that automates this task for him.

A man holding a device that waves two small rainbow flagsNow there’s a bit more involved in designing a proper flag-waver than simply moving the flag back and forth. Ideally, the fabric should flow smoothly from side to side and show both sides equally, in the same way a human would do when waving a big flag around. After a bit of research [Mellow] decided on a design that generates a rather complex motion using just a single servo: the mast is tilted from left to right, while gravity ensures the flag rotates around its axis. It’s probably best demonstrated visually, as [Mellow] does in the video embedded below.

The flag-waving mechanism is designed in Fusion 360 and 3D printed using white filament. Inside a little square box is a Wemos D1 Mini, powered by a lithium battery scavenged from a vape pen, as well as a battery management system and a power switch. The servo sits on top of the box and holds the flag in a little socket that allows the mast to rotate freely. [Mellow] also went one step further and built a two-flag waver, which still uses only one servo but creates two opposite motions through a set of spur gears. Both waver types bring a lively atmosphere to their surroundings, and we can actually imagine them being useful in places like sports bars.

Automatic flag-wavers are still rare devices, and as far as we can tell this is only the second one we’ve seen, after this hat-mounted example. That is, if you don’t count the automatic “flag” on this mailbox.

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