Hacklet 91: Ultrasonic Projects

Ultrasound refers to any audio signal above the range of human hearing. Generally that’s accepted as 20 kHz and up. Unlike electromagnetic signals, ultrasonics are still operating in a medium – generally the air around us. Plenty of animals take advantage of ultrasonics every day. So do hackers, makers, and engineers who have built thousands of projects based upon these high frequency signals. This weeks Hacklet is all about the best ultrasonic projects on Hackaday.io!

spambakeWe start with [spambake] and World’s Smallest Bat Detector. [Spambake] is interested in bats. These amazing creatures have poor eyesight, but that doesn’t slow them down. Bats use echolocation to determine their surroundings. Ultrasonic chirps bounce off obstacles. The bat listens to the echos and changes its flight path accordingly. While we can’t hear most of the sounds bats make, electronics can. [Spambake] cooked this circuit up starting with a MEMs microphone. These microphones pick up human sounds, but unlike our ears, they can hear plenty above the 20 kHz range. The audio signal is passed through an amplifier which boosts the it up around 10,000 times. The signal is filtered and then used to trigger LEDs that indicate a bat is present. The final circuit works quite well! Check out [spambake’s] video to see the bat detector in action!

movvaNext up is [Neil Movva] with Pathfinder – Haptic Navigation. Pathfinder uses ultrasonic transducers to perform echolocation similar to bats. The received data is then passed on to a human wearer. [Neil’s] idea is to use Pathfinder to help the visually disabled and blind navigate the world around them. Pathfinder was a 2015 Hackaday Prize finalist. The ultrasonic portion of Pathfinder uses the ubiquitous HC-SR04 distance sensor, which can be found for as little as $2 USD on eBay and Alibaba. These sensors send out a 60 kHz signal and listen for the echos. A microcontroller can then measure the time delay and determine the distance from the sensor to an obstacle. Finally the data is passed on to the user by a vibrating pager motor. [Neal] was kind enough to give a talk about Pathfinder at the 2015 Hackaday SuperCon.

levitate[HoboMunching] likes his ultrasonic devices ultra powerful, and that’s just what he’s got with Ultrasonic Levitation Rig. Inspired by a similar project from Mike, [HoboMunching] had to build his own levitation setup. Ultrasonic levitation used to be a phenomenon studied only in the laboratory. Cheap transducers designed for the industrial world have made this experiment practical for the home hackers. [HoboMunching] was able to use his rig to levitate up to 8 tiny balls on the nulls between the 28.5 kHz sound waves produced by his transducer. The speed of sound can be verified by measuring the distance between the balls. Purists will be happy to hear that [HoboMunching]’s circuit was all based upon the classic 555 timer.

speaker-arrayFinally we have [Alan Green] with Ultrasonic Directional Speaker V1. Most audio signals are not very directional, due to wavelength and practical limitations on speaker size. Ultrasonics don’t have this limitation. Couple this with the fact that ultrasonic signals can be made to demodulate in air, and you have the basis for a highly directional speaker setup. “Sound lasers” based on this system have been around for years, used in everything from targeted advertising to defensive weapons. [Alan] is just getting started on this project. Much of his research is based upon [Joe Pompei’s] work at the MIT media lab. [Alan] plans to use an array of ultrasonic transducers to produce a directional signal which will then demodulate and be heard by a human. This project has a hard deadline though:  [Alan] plans to help his son [Mitchell] with a musical performance that is scheduled for May, 2016. The pair hope to have a prototype in place by March.

If you want to see more ultrasonic projects, check out our new ultrasonic projects list! If I missed your project, don’t be shy! Just drop me a message on Hackaday.io. That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Check Out Who’s Speaking at the Hackaday SuperConference

The Hackaday SuperConference is just eleven short days from now! We’ve put together a conference that is all about hardware creation with a side of science and art. Join hundreds of amazing people along with Hackaday crew for a weekend of talks, workshops, and socializing.

Below you will find the full slate of talks, and last week we revealed the lineup of hands-on workshops. We’ve expanded a few of the more popular workshops. If you previously tried to get a ticket and found they were sold out, please check again. We know many of you are working on impressive projects in your workshops, so bring them and sign up for a lightning talk at registration.

This is a gathering of people who make the hardware world go round, and that includes you. Apply now to attend the 2015 Hackaday SuperConference.

 

2015 Hackaday SuperConference Talks:

Shanni R. Prutchi

Construction of an Entangled Photon Source for Experimenting with Quantum Technologies

Minas Liarokapis

OpenBionics: Revolutionizing Prosthetics with Open-Source Dissemination

Fran Blanche

Fun and Relevance of Antiquated Technology

Danielle Applestone

Founding a hardware startup: what I wish I’d known!

Luke Iseman

Starting a Hardware Startup

Grant Imahara

Recapping Mythbusters and his Engineering Career follow by a Fireside Chat

Noah Feehan

Making in Public

Jeroen Domburg

Implementing the Tamagotchi Singularity

Sarah Petkus

NoodleFeet: Building a Robot as Art

Alvaro Prieto

Lessons in Making Laser Shooting Robots

Zach Fredin

You Can Take Your Hardware Idea Through Pilot-Scale Production With Minimal Prior Experience And Not Very Much Money, So You Should Do It NOW!!

Kate Reed

The Creative Process In Action

Oscar Vermeulen

PiDP-8: Experiences developing an electronics kit

Reinier van der Lee

The Vinduino Project

Radu Motisan

Global environmental surveillance network

David Prutchi

Construction of Imaging Polarimetric Cameras for Humanitarian Demining

Rory Aronson

Why great documentation is vital to open-source projects

Jonathan Beri

I like to move it, move it: a pragmatic guide to making your world move with motors!

Neil Movva

Adding (wearable) Haptic Feedback to Your Project

Dustin Freeman

The Practical Experience of Designing a Theatre Experience around iBeacons

Kay Igwe

Brain Gaming

Hackaday Los Angeles Event: Develop your Hacking Superpowers

When we get together we like to build stuff, and that’s what has been motivating us as we work toward Hackaday Prize Worldwide: Pasadena. This two-day event held May 9th and 10th in the Los Angeles area is not to be missed. We are presenting a workshop, speakers, hacking, and socializing. Drop what you’re doing and get a ticket for the low-low price of being an awesome person.

On Saturday the ninth, Hackaday opens our doors for the workshop: “Zero to Product”. [Matt Berggren] leads the workshop. He is well known for running the Hardware Developer’s Didactic Galactic up in San Francisco (a meetup that we love to attend). [Matt] comes from a hardware design background and has done it all. He’s been involved in building schematic and PCB tools, been run through the startup gauntlet, and has a ton of hardware experience including everything from FPGA layout to getting that product out the door.

The workshop covers the things you need to consider when producing production-quality, professional-level circuit boards. Don’t be afraid of this, the discussion is approachable for the newcomer as well as the experienced hacker. Of course a PCB does not a product make so the conversation will also move through component selection, enclosures, best practices, and much more.

You Can’t Miss these Talks

 

judge-thumb-White[Elecia White]

[Elecia] is an embedded systems expert and a Hackaday Prize judge in both 2014 and 2015. Elecia will be demonstrating a gadget designed to familiarize engineers with the capabilities of inertial various sensors like accelerometers, gyroscopes, and magnetometers.

[Samy Kamkar]

[Samy] is a privacy and security researcher, has had a number of projects featured on Hackaday. The most notable in our minds is the wireless keyboard sniffer he built into a cellphone charger. He’ll be discussing that build as well as some other projects like his drone army.

We do have a few other speakers and lighting talks lined up but we don’t want to announce until we have final confirmation from those presenters. Please check on the event page for updates.

Show Off Your Hacks and Build More On-Site

 

build
The robot build at Hackady’s 10th Anniversary last October

We have the space, we have the people, add some food and beverage and now you’re talking. On Saturday evening we’ll warp up the talks and workshops, throw on some tunes, and pull out the projects we’ve been working in our spare time.

This casual hang-out is a great time to find answers and advice for that one problem that’s been tripping you up. We’ll make sure there’s something to fill your belly and keep you happy while you think about what you want to hack on the following day.

Sunday is Open Hack Day. Want to work on the concepts you picked up from Saturday’s workshop? Great, we can help with that! We’ll also have hardware development boards on-hand from our Hackaday Prize Sponsors, other random hackable stuff, and of course you may bring your own equipment and get down to business. Anything is fair game but we’re especially excited to see what people are building as their 2015 Hackaday Prize entries!

In case you missed the ticket link, please RSVP now. We’ll see you in May!


The 2015 Hackaday Prize is sponsored by:

Auto-sleep Hacked in PC Speakers

We can commiserate with [HardwareCoder] who would rather not leave his PC speakers on all the time. The Creative T20 set that he uses turn off when you turn the volume knob all the way down until it clicks. So shutting them off means repositioning the volume each time they’re switched on again. This hack kills two birds with one stone by turning on and off automatically without touching that knob.

The system is based around an ATtiny45 and a few other simple components. It uses two ADCs to monitor the rear input channels of the PC speakers. If no sound is detected for more than one minute, the shutdown pin of the speakers’ amp chip is triggered. That’s not quite where the hack ends. We mentioned it monitors the rear input of the speakers, but it doesn’t monitor the front AUX input. An additional push button is used to disable the auto-sleep when using this front input. There is also a fancy PWM-based heartbeat on an LED when the speakers are sleeping.

[HardwareCoder] was worried that we wouldn’t be interested in this since it’s quite similar to a hack we ran a few years ago. We hope you’ll agree it’s worth another look. He also warned us that the demo video was boring. We watched it all anyway and can confirm that there’s not much action there but we embedded it below anyway.

Continue reading “Auto-sleep Hacked in PC Speakers”

Speakers at Hackaday’s 10th Anniversary

It is with great pleasure that we are able to announce the final slate of speakers for Hackaday’s 10th Anniversary on October 4th in Pasadena. There are still around 30 tickets left for the conference so get yours now!

The most recently confirmed speaker is a man of many names. [Ryan Clarke] may be better known as [LosT], [1o57], or [Lostboy]. For years he has been driving the flagship contest at DEFCON by generating cryptographic puzzles that run far and deep through the 4-day conference and beyond. His talk will venture into the art and science of putting together these challenges, and the lengths at which determined hackers will go to solve them. His site gets taken over each year for DEFCON, so you might want to explore his Twitter account if you’re looking to learn more about this mysterious figure.

The other four speakers have already been mentioned in the initial announcement and last week’s follow-up. [Steve Collins] will discuss how his early interest in hacking led him to become an engineer at NASA. [Quinn Dunki] will have her scratch-built Veronica computer on hand and explain the adventure of the impressive project. [ThunderSqueak] will help us wrap our minds around the concept of non-binary computing, and [Jon McPhalen] will present the benefits of multi-core embedded processing versus traditional interrupt-based design.

We can’t wait for this amazing afternoon of talks which is just one week from Saturday. We hope to see you there!

Homemade Omnidirectional Speakers in a Unique Enclosure

While studying acoustics in college (university for non-Americans), [Nick] had a great idea for an omnidirectional speaker. Some models available for purchase have a single speaker with a channel to route the sound in all directions, but [Nick] decided that a dodecahedron enclosure with 12 speakers would be a much more impressive route.

To accommodate the array of speakers, the enclosure needs twelve pentagons with a 58.3 degree bevel so that they fit together in a ball shape. After thinking about all of the complicated ways he could get this angle cut into the wood pentagons, he ended up using a simple circular saw!

Once the enclosure was painted [Nick] started wiring up the speakers. The equivalent impedance of the array of 8-ohm speakers works out to just around 10 ohms, which is easily driven by most amplifiers. The whole thing was hung from a custom-made galvanized pipe (all the weight adds up to about 15 kilograms, or 33 pounds for Americans, so the rig needed to be sturdy). We’ve featured other unique speaker builds, but this is the first 12-speaker omnidirectional speaker we’ve seen. [Nick] is happy to report that the speakers sound great, too!

A Hackable Hi-Fi Audio DSP

DSP 01 Hi-fi Signal Processor

 

Audiophiles tend to put analog systems on a pedestal. Analog systems can provide great audio performance, but they tend to be quite costly. They’re also hard to tinker with, since modifying parameters involves replacing components. To address this, [tshen2] designed the DSP 01.

The DSP 01 is based around the Analog Devices ADAU1701. This DSP chip includes two ADCs for audio input, and four DACs for audio output. These can be controlled by the built in DSP processor core, which has I/O for switches, buttons, and knobs.

[tshen2]’s main goal with the DSP 01 was to implement an audio crossover. This device takes an input audio signal and splits it up based on frequency so that subwoofers get the low frequency components and tweeters get the higher frequency components. This is critical for good audio performance since drivers can only perform well in a certain part of the audio spectrum.

Analog Devices provides SigmaStudio, a free tool that lets you program the DSP using a drag-and-drop interface. By dropping a few components in and programming to EEPROM, the DSP can be easily reconfigured for a variety of applications.