DIY Piano: Look, Ma, No Moving Parts

April 6, 2019 by Brian McEvoy 5 Comments

[Michael Sobolak] has a penchant for pianos, concern for capacitive touch, and special sentiment for solid state. This alliterate recipe results in a DIY PCB piano that leaves out the levers and is barren of buttons unless you count the stock RESET button on the Teensy. A real stickler might point out that speakers have moving cones. Beyond these tangential parts, which have motionless options, it is an electronic instrument with no moving parts.

The heart of the project is a Teensy 3.2 which natively supports twelve capacitive touch sensors. The infamous demo board is mounted to a homemade PCB featuring twelve keys but is actually an incomplete octave plus another key one octave above the first. If you look sharp, you already noticed the missing and extra touchpads. PCB traces were made in Illustrator because if you have a familiar tool, you use what you know and you cannot argue that it works. The design was transferred to a copper board using the old magazine page trick that we love and reliable old ferric acid.

We couldn’t help but notice that the posts of the Teensy were soldered to the top of the board, rather than drilling through, IMT-style. Again, the results speak, even if there is room for improvement. Reportedly, there is a second version on the way which includes every expected key.

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You Are Your Own Tactile Feedback

February 15, 2019 by Brian McEvoy 1 Comment

[Maurin Donneaud] has clearly put a lot of work into making a large flexible touch sensitive cloth, providing a clean and intuitive interface, and putting it out there for anyone to integrate into their own project.. This pressure sensing fabric is touted as an electronic musical interface, but if you only think about controlling music, you are limiting yourself. You could teach AI to land a ‘copter more evenly, detect sparring/larping strikes in armor, protect athletes by integrating it into padding, or measure tension points in your golf swing, just to name a few in sixty seconds’ writers brainstorming. This homemade e-textile measures three dimensions, and you can build it yourself with conductive thread, conductive fabric, and piezoresistive fabric. If you were intimidated by the idea before, there is no longer a reason to hold back.

The idea is not new and we have seen some neat iterations but this one conjures ideas a mile (kilometer) a minute. Watching the wireframe interface reminds us of black-hole simulations in space-time, but these ones are much more terrestrial and responding in real-time. Most importantly they show consistent results when stacks of coins are placed across the surface. Like most others out there, this is a sandwich where the slices of bread are ordinary fabric and piezoresistive material and the cold cuts are conductive strips arranged in a grid. [Maurin] designed a custom PCB which makes a handy adapter between a Teensy and houses a resistor network to know which grid line is getting pressed.

If you don’t need flexible touch surfaces, we can help you there too.

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Freeform Wire Frame Tulip Blooms To The Touch

February 12, 2019 by Roger Cheng 5 Comments

Holidays are always good for setting a deadline for finishing fun projects, and every Valentine’s Day we see projects delivering special one-of-a-kind gifts. Why buy a perishable bulk-grown biological commodity shipped with a large carbon footprint when we can build something special of our own? [Jiří Praus] certainly seemed to think so, his wife will receive a circuit sculpture tulip that blooms when she touches it.

This project drew from [Jiří]’s experience with aesthetic LED projects. His Arduino-powered snowflake, with LEDs mounted on a custom PCB, is a product available on Tindie. For our recent circuit sculpture contest, his entry is a wire frame variant on his snowflake. This tulip has 7 Adafruit NeoPixel in the center and 30 white SMD LEDs in the petals, which look great. But with the addition of mechanical articulation, this project has raised the bar for all that follow.

We hope [Jiří] will add more details for this project to his Hackaday.io profile. In the meantime, look over his recent Tweets for more details on how this mechanical tulip works. We could see pictures and short videos of details like the wire-and-tube mechanism that allowed all the petals to be actuated by a single servo, and the components that are tidily packaged inside that wooden base.

Need more digital expressions of love? We have no shortage of hearts. Animated LED hearts, illuminated acrylic hearts, and talking hearts. We’re a little short on flower projects, but we do have X-ray of a rose among others to accompany [Jiří]’s tulip.

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Redesigning The Musical Keyboard With Light-Up Buttons

November 4, 2018 by Brian Benchoff 13 Comments

A piano’s keyboard doesn’t make sense. If you want to want to play an F major chord, just hit an F, an A, and a C — all white keys, all in a row. If you want to play a B major chord, you hit B, a D#, and an F#. One white key, then two black ones. The piano keyboard is not isomorphic, meaning chords of the same quality have different shapes. For their entry into the Hackaday Prize, [CSCircuits] and their crew are working on a keyboard that makes chords intuitive. It’s called the Kord Kontroller, and it’s a device that would also look good hooked up to Ableton.

The layout of the Kord Kontroller puts all the scale degrees arranged in the circle of fifths in the top of the keyboard. To play 90% of western music, you’ll hit one button for a I chord, move one button to the left for a IV chord, and two buttons to the right for a V chord. Chord quality is determined by the bottom of the keyboard, with buttons for flat thirds, fourths, ninths, elevenths and fourteenths replacing or augmenting notes in the chords you want to play. Since this is effectively a MIDI controller, there are buttons to change octaves and modes.

As far as hardware goes, this keyboard is constructed out of Adafruit Trellis modules that are a 4×4 grid of silicone buttons and LEDs that can be connected together and put on a single I2C bus. The enclosure wraps these buttons up into a single 3D printed grid of button holes, and with a bit of work and hot glue, everything looks as it should.

It’s an interesting musical device, and was named as a finalist in the Musical Instrument Challenge. You can check out a demo video with a jam sesh below.

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Touch Anything And Everything

September 19, 2018 by Brian McEvoy 10 Comments

Powering IoT devices is often a question of batteries or mains power, but in rare exceptions to this rule there is no power supply (PDF Warning). At the University of Wisconsin-Madison and the University of California, San Diego, researchers have gone the extra mile to make advanced backscatter devices, and these new tags don’t need the discrete components we have seen in previous versions. They are calling it LiveTag, and it doesn’t need anything aside from a layer of foil printed or etched on a flexible ceramic-PTFE laminate. PTFE is mostly seen in the RF sector as a substrate for circuit boards.

We have seen some of the wild creations with wifi backscatter that range from dials to pushbuttons. RF backscatter works by modulating the RF signals in which we are continuously swimming. Those radio waves power the device and disrupt the ambient signals, which disruption can be detected by a receiver. With a BOM that looks like a statement more than a list, integration with many devices becomes a cost-effective reality. Do not however broadcast important data because you cannot expect great security from backscatter.

[Via IEEE Spectrum]

Roll Up Your Sleeve, Watch A Video With This Smart Watch Forearm Projector

April 25, 2018 by Dan Maloney 35 Comments

We’re all slowly getting used to the idea of wearable technology, fabulous flops like the creepy Google Glass notwithstanding. But the big problem with tiny tech is in finding the real estate for user interfaces. Sure, we can make it tiny, but human fingers aren’t getting any smaller, and eyeballs can only resolve so much fine detail.

So how do we make wearables more usable? According to Carnegie-Mellon researcher [Chris Harrison], one way is to turn the wearer into the display and the input device (PDF link). More specifically, his LumiWatch projects a touch-responsive display onto the forearm of the wearer. The video below is pretty slick with some obvious CGI “artist’s rendition” displays up front. But even the somewhat limited displays shown later in the video are pretty impressive. The watch can claim up to 40-cm² of the user’s forearm for display, even at the shallow projection angle offered by a watch bezel only slightly above the arm — quite a feat given the irregular surface of the skin. It accomplishes this with a “pico-projector” consisting of red, blue, and green lasers and a pair of MEMS mirrors. The projector can adjust the linearity and brightness of the display to provide a consistent image across the uneven surface. An array of 10 time-of-flight sensors takes care of watching the display area for touch input gestures. It’s a fascinating project with a lot of potential, but we wonder how the variability of the human body might confound the display. Not to mention the need for short sleeves year round.

Need some basics on the micro-electrical mechanic systems (MEMS) behind the pico-projector in this watch? We’ve got a great primer on these microscopic machines.

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Everything’s A Touch Surface With Electrick

May 18, 2017 by Al Williams 10 Comments

Touch screens are great, but big touchscreens are expensive and irregular touchscreens are not easy to make at all. Electrik is a method developed by several researchers at Carnegie Mellon University that makes almost any solid object into a touch surface using tomography. The catch is that a conductive coating — in the form of conductive sheets, 3D plastic, or paint — is necessary. You can see a demonstration and many unique applications in the video below. They’ve even made a touch-sensitive brain out of Jell-O and a touchable snowman out of Play-Doh.

The concept is simple. Multiple electrodes surround the surface. The system injects a current using a pair of electrodes and then senses the output at the other terminals. A finger touch will change the output of several of the electrodes. Upon detection, the system will change the injection electrodes and repeat the sensing. By using multiple electrode pairs and tomography techniques, the system can determine the location of touch and even do rough motion tracking like a low-resolution touch pad mouse.

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