Acoustic Levitation with a Twist

Don’t blame us for the click-baity titles in the source articles about this handheld “acoustic tractor beam”. You can see why the popular press tarted this one up a bit, even at the risk of drawing the ire of Star Trek fans everywhere. Even the journal article describing this build slipped the “tractor beam” moniker into their title. No space vessel in distress will be towed by [Asier Marzo]’s tractor beam, unless the aliens are fruit flies piloting nearly weightless expanded polystyrene beads around the galaxy.

That doesn’t detract from the coolness of the build, revealed in the video below. There’s no tutorial per se, but an Instructables post is promised. Still, a reasonably skilled hacker will be able to replicate the results with ease straight from the video. Using mostly off the shelf hardware, [Marzo] creates a bowl-shaped phased array of ultrasonic transducers driven by an Arduino through a DC-DC converter and dual H-bridge driver board to boost the 40 kHz square waves from 5 Vpp to 70 Vpp. By controlling the phasing of the signals, the tractor beam can not only levitate small targets but also move them axially. It looks like a lot of fun.

Acoustic levitation is nothing new here – we’ve covered 3D acoustic airbending, as well as an acoustic flip-dot display. Being able to control the power of sound waves in a handheld unit is a step beyond, though.

Continue reading “Acoustic Levitation with a Twist”

Hackaday Prize Entry: Ears On The Back Of Your Head

From context clues, we can tell that [TVMiller] has been in and around NYC for some time now. He has observed a crucial weakness in the common metropolitan. Namely, they deafen themselves with earphones, leaving them senseless in a hostile environment.

To fix this problem, he came up with a simple hack, the metrophone. An ultrasonic sensor is hung from a backpack. The user’s noise making device of choice is plugged into one end, and the transducer into the other. When the metropolitan is approached from the rear by a stalking tiger or taxi cab, the metrophone will reduce the volume and allow the user to hear and respond to their impending doom. Augmentation successful.

The device itself consists of an off-the-shelf ultrasonic sensor, an Arduino, and a digital potentiometer. It all fits in a custom 3D printed enclosure and runs of two rechargeable coin cells. A simple bit of code scales the volume to the current distance being measured by the ultrasonic sensor once a threshold has been met.

In the video after the break, you can observe [TVMiller]’s recommended method for tranquilizing and equipping a metropolitan in its natural habitat without disturbing its patterns or stressing it unduly.

Continue reading “Hackaday Prize Entry: Ears On The Back Of Your Head”

Self-Driving Cars Get Tiny

There’s a car race going on right now, but it’s not on any sort of race track. There’s a number of companies vying to get their prototype on the road first. [Anurag] has already completed the task, however, except his car and road are functional models.

While his car isn’t quite as involved as the Google self driving car, and it doesn’t have to deal with pedestrians and other active obstacles, it does use a computer and various sensors to make decisions about how to drive. A Raspberry Pi 2 takes the wheel in this build, taking input from a Pi camera and an ultrasonic distance sensor. The Pi communicates to another computer over WiFi, where a neural network operates to make decisions about how to drive the car. It also makes decisions based on a database of pictures of the track, so it has a point of reference to go by.

The video of the car in action is worth a look. It’s not perfect, but it’s quite an accomplishment for this type of project. The possibility that self-driving car models could drive around model sets like model railroad hobbyists create is intriguing. Of course, this isn’t [Anurag]’s first lap around the block. He’s already been featured for building a car that can drive based on hand gestures. We’re looking forward to when he can collide with model busses.

Continue reading “Self-Driving Cars Get Tiny”

An Affordable Ultrasonic Soldering Iron

One of the most interesting facets of our community of hackers and makers comes from its never-ending capacity to experiment and to deliver new technologies and techniques. Ample demonstration of this came this morning, in the form of [Hunter Scott]’s project to create an ultrasonic soldering iron. This is a soldering technique in which the iron is subjected to ultrasonic vibrations which cavitate the surface of the materials to be soldered and remove any oxides which would impede the adhesion of the solder. In this way normally unsolderable materials such as stainless steel, aluminium, ceramic, or glass can be soldered without the need for flux or other specialist chemicals. Ultrasonic soldering has been an expensive business, and [Hunter]’s project aims to change that.

This iron takes the element and tip from a conventional mains-powered soldering iron and mounts it on the transducer from an ultrasonic cleaner. The transducer must be given an appropriate load which in the case of the cleaner is furnished by a water bath, or it will overheat and burn out. [Hunter]’s load is just a soldering iron element, so to prevent transducer meltdown he keeps the element powered continuously but the transducer on a momentary-action switch to ensure it only runs for the short time he’s soldering. The project is not quite finished so he’s yet to prove whether this approach will save his transducer, but we feel it’s an interesting enough idea to make it definitely worth following.

This is the first ultrasonic soldering project we’ve featured here at Hackaday. We have however had an ultrasonic plastic welder before, and an ultrasonic vapour polisher for 3D prints. It would be good to think this project could spark a raft of others that improve and refine DIY ultrasonic soldering designs.

Hackaday Dictionary: Ultrasonic Communications

Say you’ve got a neat gadget you are building. You need to send data to it, but you want to keep it simple. You could add a WiFi interface, but that sucks up power. Bluetooth Low Energy uses less power, but it can get complicated, and it’s overkill if you are just looking to send a small amount of data. If your device has a microphone, there is another way that you might not have considered: ultrasonic communications. Continue reading “Hackaday Dictionary: Ultrasonic Communications”

Augmented Reality Ultrasound

Think of Virtual Reality and it’s mostly fun and games that come to mind. But there’s a lot of useful, real world applications that will soon open up exciting possibilities in areas such as medicine, for example. [Victor] from the Shackspace hacker space in Stuttgart built an Augmented Reality Ultrasound scanning application to demonstrate such possibilities.

But first off, we cannot get over how it’s possible to go dumpster diving and return with a functional ultrasound machine! That’s what member [Alf] turned up with one day. After some initial excitement at its novelty, it was relegated to a corner gathering dust. When [Victor] spotted it, he asked to borrow it for a project. Shackspace were happy to donate it to him and free up some space. Some time later, [Victor] showed off what he did with the ultrasound machine.

As soon as the ultrasound scanner registers with the VR app, possibly using the image taped to the scan sensor, the scanner data is projected virtually under the echo sensor. There isn’t much detail of how he did it, but it was done using Vuforia SDK which helps build applications for mobile devices and digital eye wear in conjunction with the Unity 5 cross-platform game engine. Check out the video to see it in action.

Thanks to [hadez] for sending in this link.

Continue reading “Augmented Reality Ultrasound”

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!

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 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!