Chordata motion capture dancer and 3D model

A Motion Capture System For Everyone

September 24, 2018 by Steven Dufresne 23 Comments

[Chordata] is making a motion capture system for everyone to build and so far the results are impressive, enough to have been a finalist in the Hackaday Human Computer Interface Challenge. It started a few years ago as one person’s desire to capture a digital performance of a dancer on a stage and has grown into a community of contributors. The board files and software have just been released as alpha along with some instructions for making it work, though more detailed documentation is on the way.

Fifteen sensor boards, called K-Ceptors, are attached to various points on the body, each containing an LSM9DS1 IMU (Inertial Measurement Unit). The K-Ceptors are wired together while still allowing plenty of freedom to move around. Communication is via I2C to a Raspberry Pi. The Pi then sends the collected data over WiFi to a desktop machine. As you move around, a 3D model of a human figure follows in realtime, displayed on the desktop’s screen using Blender, a popular, free 3D modeling software. Of course, you can do something else with the data if you want, perhaps make a robot move? Check out the overview and the performance by a clearly experienced dancer putting the system through its paces in the video below.

As a side note, the latest log entry on their Hackaday.io page points out that whenever changes are made to the K-Ceptor board, fifteen of them need to be made in order to try it out. To help with that, they show the testbed they made for troubleshooting boards as soon as they come out of the oven.

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Send Smooches Over Skype With The Kiss Interface

September 23, 2018 by Donald Papp 14 Comments

This project of [Nathan]’s certainly has a playful straightforwardness about it. His Skype ‘Kiss’ Interface has a simple job: to try to create a more intuitive way to express affection within the limits of using Skype. It all came about from a long distance relationship for which the chat program was the main means of communicating. Seeking a more intuitive and personal means of expressing some basic affection, [Nathan] created a capacitive touch sensor that, when touched with the lips, sends the key combination for either a kissy face emoji or the red lips emoji, depending on the duration.

Capacitive touch sensing allows for triggering the sensor without actually physically touching one’s lips to the electrodes, which [Nathan] did by putting a clear plastic layer over the PCB traces. His board uses an STM32 microcontroller with software handling the USB HID and STM’s TSC (Touch Sensing Controller) functionality. As a result, the board has few components and a simple interface, which was in keeping with the goal of rejecting feature creep and focusing on a simple task.

Clearly the unit works; but how well does it actually fulfill its intended purpose? We don’t know that yet, but we do know that [Nathan] seems to have everything he needs in order to find out. Either way, it’s a fun project that definitely fits the spirit of the Human-Computer Interface Challenge of The Hackaday Prize.

Serpentine: multi-purpose hand gesture sensor

There Are Multiple Ways To Gesture With This Serpentine Sensor

September 22, 2018 by Steven Dufresne 3 Comments

Serpentine is a gesture sensor that’s the equivalent of a membrane potentiometer, flex and stretch sensor, and more. It’s self-powering and can be used in wearable hacks such as the necklace shown in the banner image though we’re thinking more along the lines of the lanyard for Hackaday conference badges, adding one more level of hackability. It’s a great way to send signals without anyone else knowing you’re doing it and it’s easy to make.

Serpentine is the core of a research project by a group of researchers including [fereshteh] of Georgia Tech, Atlanta. The sensor is a tube made of a silicone rubber and PDMS (a silicone elastomer) core with a copper coil wrapped around it, followed by more of the silicone mix, a coil of silver-coated nylon thread, and a final layer of the silicone mix. Full instructions for making it are on their Hackaday.io page.

There are three general interactions you can have with the tube-shaped sensor: radial, longitudinal, and tangential. Doing various combinations of these three results in a surprising variety of gestures such as tap, press, slide, twist, stretch, bend, and rotate. Those gestures result in signals across the copper and silver-coated nylon electrodes. The signals pass through an amplifier circuit which uses WiFi to send them on to a laptop where signal processing distinguishes between the gestures. It recognizes the different ones with around 90% accuracy. The video below demonstrates the training step followed by testing.

Serpentine works as a result of the triboelectric nanogenerator (TENG) phenomenon, a mix of the triboelectric effect and electrostatic induction but fabrics can be made which use other effects too. One example is this fabric keyboard and theremin which works in part using the piezoelectric effect.

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The Diaphragm Is The Coil In These Flexible PCB Speakers

September 21, 2018 by Dan Maloney 10 Comments

Speakers used to be largish electromechanical affairs, with magnets, moving coils, and paper cones all working together to move air around in a pleasing way. They’ve gotten much smaller, of course, small enough to screw directly into your ears or live inside the slimmest of smartphones and still delivery reasonable sound quality. The basic mechanism hasn’t changed much, but that doesn’t mean there aren’t other ways to make transduce electrical signals into acoustic waves.

Take these speakers made from flexible printed circuit boards, for instance. While working on his flexible PCB soft actuators, [Carl Bugeja] noticed that the PWM signals coursing through the coils on the thin PCB material while they were positioned over a magnet made an audible beeping. He decided to capitalize on that and try to make a decent speaker from the PCBs. An early prototype hooked to a simple amplifier showed promise, so he 3D-printed a ring to support the PCB like a diaphragm over a small neodymium magnet. The sound quality was decent, but the volume was low, so [Carl] experimented with a paper cone attached to the PCB to crank it up a bit. That didn’t help much, but common objects acting as resonators seemed to work fairly well. Check out the results in the video below.

This is very much a work in progress, but given [Carl]’s record with PCB creations from robotic fish to stepper motors built right into the PCB, we’d say he’ll make substantial improvements. Follow his and others’ progress in the Musical Instruments Challenge part of the 2018 Hackaday Prize.

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This Keyboard And Mouse Also Gives You A Workout

September 20, 2018 by Brian Benchoff 2 Comments

The Ergonomic Handheld Mouse / Keyboard Alternative from [Shervin Emami] is an all-in-one solution for your keyboarding and cursor moving needs.

The core of this build is a ‘grip-strengthening’ device that’s sold to guitarists. While the actual benefit of these devices for guitarists is questionable — there are a few anecdotes any music teacher will tell you about classical pianists ruining their hands with similar devices — the device itself can be converted into a fantastic chording keyboard. All you really need for a full-functioned keyboard is a few buttons in a rugged shell, and this ‘grip strengthener’ has that going in spades.

Underneath the plungers for each button [Shervin] installed a magnet and a magnetic sensor, meaning these buttons are analog, and shouldn’t wear out ever. With just a little bit of code on a Tiny BLE board these analog sensors can become a keyboard, a quadcopter controller, an interface for your VR setup, or anything else that can be controlled with a bunch of buttons.

Not to outdo himself, [Shervin] also managed to add some cursor control functionality to this build. This is done via the IMU onboard the Tiny BLE board, and by all accounts it works great. You can check out a video of this build pretending it’s both a keyboard and a mouse below.

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‘SHE BON’ Is An Artful, Wearable, Sensual, Sensing Platform

September 19, 2018 by Donald Papp 16 Comments

SHE BON (that’s the French bon, or “good”) is an ambitious project by [Sarah Petkus] that consists of a series of wearable electronic and mechanical elements which all come together as a system for a single purpose: to sense and indicate female arousal. As a proponent of increased discussion and openness around the topic of sexuality, [Sarah]’s goal is to take something hidden and turn it into something obvious and overt, while giving it a certain artful flair in the process.

The core of the system is a wearable backpack in the shape of a heart, from which all other sensors and feedback elements are connected. A lot of thought has gone into the design of the system, ensuring that the different modules have an artistic angle to their feedback while also being comfortable to actually wear, and [Sarah] seems to have a knack for slick design. Some of the elements are complete and some are still in progress, but the system is well documented with a clear vision for the whole. It’s an unusual and fascinating project, and was one of the finalists selected in the Human Computer Interface portion of the 2018 Hackaday Prize. Speaking of which, the Musical Instrument Challenge is underway, so be sure check it out!

Man’s Best Robotic Friend

September 17, 2018 by Brian Benchoff 4 Comments

When it comes to robotics, some of the most interesting work — and certainly the most hilarious — has come from Boston Dynamics, and their team of interns kicking robotic dogs over. It’s an impressive feat of engineering, and even if these robotic pack mules are far too loud for their intended use on the battlefield, it’s a great showcase of how cool a bunch of motors can actually be.

It’s not quite up there with the Boston Dynamics robots, but [Dimitris]’ project for the Hackaday Prize is an almost equally impressive assemblage of motors, 3D printed parts, SLAM processing and inverse kinematics. I suppose you could also kick it over and watch it struggle for laughs, too.

This robotic dog was first modeled in Fusion 360, and was designed with 22 Dynamixel AX-12A robot actuators: big, beefy, serial-controllable servos. Of course, bolting a bunch of motors to a frame is the easy part. The real challenge here is figuring out the kinematics and teaching this robot dog how to walk. This is still a work in progress, but so far [Dimitris] is able to move the spine, keep the feet level with the ground, and have the robot walk a little bit. There’s still work to do, but there’s an incredible amount of work that’s already been done.

The upcoming features for this robot include a RealSense camera mounted on the head for 3D visualization of the surroundings. There’s also plans for a tail, loosely based on some of the tentacle robots we’ve seen. It’s going to be a great project when it’s done, and it’s already an excellent entry for the Hackaday Prize.

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