Autonomous Musical Soundscapes from 42 Fans and 7 Lasers

[dmitry] writes in to let us know about a new project that combines lasers with fans and turns the resulting modulation of the light beams into an autonomous soundscape. The piece is called “divider” and is a large, wall-mounted set of rails upon which seven red lasers are mounted on one end with seven matching light sensors mounted on the other end. Interrupting the lasers’ paths are forty-two brushless fans. Four Arduino Megas control the unit.

3Laser beams shining into light sensors don’t do much of anything on their own, but when spinning fan blades interrupt each laser beam it modulates the solid beams and turns the readings of the sensors on the far end into a changing electrical signal which can be played as sound. Light being modulated by fan blades to create sound is the operating principle behind a Fan Synth, which we’ve discussed before as being a kind of siren (or you can go direct to that article’s fan synth demo video to hear what kind of sounds are possible from such a system.)

This project takes this entire concept of a fan synth further by not only increasing the number of lasers and fans, but by tying it all together into an autonomous system. The lasers are interrupted repeatedly and constantly, but never simultaneously. Listen to and watch it in action in the video below.

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Taming Robot Arm Jump with Accelerometers

Last fall, I grabbed a robot arm from Robot Geeks when they were on sale at Thanksgiving. The arm uses servos to rotate the base and move the joints and gripper. These work well enough but I found one aspect of the arm frustrating. When you apply power, the software commands the servos to move to home position. The movement is sufficiently violent it can cause the entire arm to jump.

This jump occurs because there is no position feedback to the Arduino controller leaving it unable to know the positions of the arm’s servos and move them slowly to home. I pondered how to add this feedback using sensors, imposing the limitation that they couldn’t be large or require replacing existing parts. I decided to try adding accelerometers on each arm section.

Accelerometers, being affected by gravity when on a planet, provide an absolute reference because they always report the direction of down. With an accelerometer I can calculate the angle of an arm section with respect to the direction of gravitational acceleration.

Before discussing the accelerometers, take a look at the picture of the arm. An accelerometer would be added to each section of the arm between the controlling servos.

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Minecraft Trojan Horse Teaches Kids to Love Electronics and Code

Kids love Minecraft, and a clever educator can leverage that love to teach some very practical skills. The summer class offered by the Children’s Museum in Bozeman Montana would have blown my mind if such a thing existed when we were younger. (Rather than begging one of the dads in my Boy Scout Troop to pirate Visual Studio for me, which was delivered in the form of an alarmingly tall stack of CDs.) The kids in Bozeman get to learn hardware, software, their integration, and all while playing Minecraft.

Minecraft is an immersive universe that has proven to suck in creative minds. It’s the bait that pulls the kids into the summer class but Serialcraft delivers on making the learning just as addictive. This is accomplished by providing students with physical objects that are tied to the Minecraft world in meaningful ways we just haven’t seen before (at least not all at one time). On the surface this adds physical LEDs, toggle switches, potentiometers, and joysticks to the game. But the physical controls invite understanding of the mechanisms themselves, and they’re intertwined in exciting ways, through command blocks and other in-game components that feel intuitive to the students. From their understanding of the game’s mechanics they understand the physical objects and immediately want to experiment with them in the same way they would new blocks in the game.

The thing that makes this magic possible is a Minecraft mod written by [John Allwine], who gave us a demonstration of the integration at Maker Faire Bay Area 2016. The mod allows the user to access the inputs and output of the Arduino, in this case a Pololu A-Star 32U4, from within Minecraft. For the class this is all packaged nicely in the form of a laser cut controller. It has some LEDs, two joysticks, buttons, potentiometers, and a photosensor.

As you can see in the video below the break, it’s really cool. The kids have a great time with it too. For example, [John] showed them how they can attach their unique controller to a piston in the world. Since this piston can be controlled by them alone, they quickly figured out how to make secret safe rooms for their items.

Another troublesome discovery, was that the photo transistor on the controller set the light level in the game world by altering the time of day. Kids would occasionally get up and change the world from day to night, by turning the lights in the room on or off. A feature that has a certain appeal for any Minecraft player, is rigging one of the LEDs on the controller to change brightness depending on proximity to a creeper.

There’s a lot more to the library, which is available on GitHub. The kids (and adults) have a great time learning to link the real world with the world’s most accessible fantasy world creation kit.  Great work [John]!

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How To Keep An Unruly Dryer In Line

If necessity is the mother of invention, then inconvenience is its frustrating co-conspirator. Faced with a finicky dryer that would shut down mid-cycle with a barely audible beep if its load was uneven (leaving a soggy mass of laundry), [the0ry] decided to add the dryer to the Internet of Things so it could send them an email whenever it shut itself down.

After opening a account, adding the soon-to-be device, and setting up the email notification process, [the0ry] combined the ESP8266 Development Board, a photosensitive resistor, and a 5V power supply on a mini breadboard. All that was left was to mount it on the dryer and direct the LDR (light-dependent resistor) to the machine’s door lock LED to trigger an email when it turned off — indicating the cycle had finished or terminated prematurely. A little tape ensured the LDR would only be tripped by the desired light source.

If you’re an apartment-dweller have WiFi in the wash area it would be awesome to see a battery-powered version you take with you. But in general this is a great hardware blueprint as many device have status LEDs that can be monitored in a similar way. If you want to keep the server in-house (literally in this case) check out the Minimal MQTT series [Elliot Williams] recently finished up. It uses a Raspberry Pi as the center server and an ESP8266 is one of the limitless examples of hardware that plays nicely with the protocol.

We love seeing hacks like this because not only does it conserve water and energy by reducing instances of rewashing, but it’s also a clever way to extend the life of an appliance and potentially save hundreds of dollars in replacing it. Add this to the bevvy of hacks that add convenience to one’s home — some of which produce delicious results.

A Robot In A Day

While building a robot (nearly) from scratch isn’t easy, it needn’t be a lengthy process.  Is it possible to build a bot in a single day? With some musical motivation (a 10 hour loop of the A-Team theme song), [Tyler Bletsch] answers with a resounding ‘yes’ in the shape of his little yellow robot that he built for a local robotics competition.

Designing and fabricating on the fly, [Bletsch] used Sketchup to design the chassis, and OpenSCAD to model the wheels while the former was being 3D printed. Anticipating some structural weakness, he designed another version that could bolt to wood if the original failed, but the addition of some metal support rods provided enough stability. Mouse pad material gave the wheels ample traction. An Arduino with the L298 control module receives input via an HC-06 Bluetooth board. Eight AA batteries provide 12V of power to two Nextrox mini 12V motors with an integrated voltmeter to measure battery life.

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A Slide Viewer Makes An Excellent Case For An OLED Project

Sometimes when browsing the websites of our global hackspace community you notice a project that’s attractive not necessarily because of what it does or its technology but because of its presentation. So it is with the subject of this article, [Kris] needed a house temperature monitor and found a 1960s slide viewer made an excellent choice for its housing.

The monitor itself is a fairly straightforward Arduino build using a couple of DS18B20 1-wire temperature sensors and a real-time-clock module and displaying their readings on a small OLED screen. Its code can be found on this mailing list thread if you are interested. The display presented a problem as it needed to be reasonably large, yet fairly dim so it could be read at night without being bright enough to interrupt sleep.

A variety of projection techniques were tried, involving lenses from a projection clock, a magnifying glass, and a Google Cardboard clone. Sadly none of these lenses had the required focal length. Eventually the slide viewer was chosen because it was pointed out that the OLED screen was about the same size as a photographic slide.

Slide viewers are part of the familiar ephemera of the analog era that most people over 60 may still have taking up drawer space somewhere but may well be completely alien to anyone under about 30. They were a magnification system packaged up into a console usually styled to look something like a small portable TV of the day, and different models had built-in battery lights, or collected ambient light with a mirror. The screen was usually a large rectangular lens about 100mm(4″) diagonal.

[Kris]’s Vistarama slide viewer came via eBay. It’s not the smallest of viewers, other models folded their light paths with mirrors, however the extra space meant that the Arduino fit easily. The OLED was placed where the slide would go, and its display appeared at just the right magnification and brightness. Job done, and looking rather stylish!

We’ve not featured a slide viewer before here at Hackaday, though we did recently feature a similar hack on an Ikea toy projector. We have however featured more than one digital conversion on a classic slide projector using LCD screens in place of the slide.

Via Robots and Dinosaurs makerspace, Sydney.

Arduino Meets da Vinci in a Gesture-controlled Surgical Robot

Lots of us get to take home a little e-waste from work once in a while to feed our hacking habits. But some guys have all the luck and score the really good stuff, which is how these robotic surgical tools came to be gesture controlled.

The lucky and resourceful hacker in this case is one [Julien Schuermans], who managed to take home pieces of a multi-million dollar da Vinci Si surgical robot. Before anyone cries “larcency”, [Julien] appears to have come by the hardware legitimately – the wrist units of these robots are consumable parts costing about $2500 each, and are disposed of after 10 procedures. The video below makes it clear how they interface with the robot arm, and how [Julien] brought them to life in his shop. A quartet of Arduino-controlled servos engages drive pins on the wrist and rotates pulleys that move the cables that drive the instruments. A neat trick by itself, but when coupled with the Leap Motion controller, the instruments become gesture controlled. We’re very sure we’d prefer the surgeon’s hands on a physical controller, but the virtual control is surprisingly responsive and looks like a lot of fun.

When we talk about da Vinci around here, it’s usually in reference to 3D printers or a Renaissance-style cryptex build. Unsurprisingly, we haven’t featured many surgical robot hacks – maybe it’s time we started.

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