ultrasonic

125 Articles

Fail Of The Week: The Little Ultrasonic Knife That Couldn’t

February 27, 2018 by 44 Comments

We all know the feeling of an idea that sounded great when it was rattling around in our head, only to disappoint when we actually build the thing. It’s a natural consequence of trying new stuff, and when it happens, we salvage what we can and move on, hopefully in wisdom.

The thing that at least semi-defeated [This Old Tony] was an attempt to build an ultrasonic cutter, and it didn’t go well. Not that any blood was shed in the video below, although there seemed like there would be the way [Old Tony] was handling those X-Acto blades. His basic approach was to harvest the transducer and driver from a cheap ultrasonic cleaner and retask the lot into a tool to vibrate a knife rapidly enough to power it through tough materials with ease.

Spoiler alert: it didn’t work very well. We think the primary issue was using a transducer that was vastly underpowered compared to commercial (and expensive) ultrasonic cutters, but we suspect the horn he machined was probably not optimized either. To be fair, modeling the acoustic performance of something like that isn’t easy, so we can’t expect much. But still, it seems like the cutter could have worked better. Share your thoughts on how to make version 2.0 better in the comments.

The video is longish, but it’s as entertaining as any of [Old Tony]’s videos, and packed full of incidental gems, like the details of cavitation. We enjoyed it, even if the results were suboptimal. If you want to see a [This Old Tony] project that really delivers, check out his beautiful boring head build.

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Automating Your Door For $20

January 11, 2018 by 12 Comments

We love the doors on Star Trek’s Enterprise. We should have known they were human-operated though because they were too smart. They would wait for people, or fail to open when someone was thrown against them during a fight. [SieuweE] has a much more practical automatic door that he calls ArduDoor.

You might guess from the name it uses an Arduino. It also uses a windshield wiper motor which is perfect since it is high-torque and low speed. You might even be able to pick one up for little or nothing if you frequent the junkyards.

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Never Let Your Christmas Tree Run Dry, With Added Ultrasound

December 9, 2017 by 10 Comments

Winter in the parts of the Northern Hemisphere for which observing Christmas includes bringing half a forest into the house should really be divided into two seasons. No-spruce-needles-in-the-carpet season, and spruce-needles-doggedly-clinging-to-the-carpet season. Evergreen trees were not designed for indoor use, and for a hapless householder to stand any chance of keeping those needles on the branches there has to be a significant amount of attention paid to the level of the water keeping the tree hydrated.

[Evan] has paid that attention to the problem of Christmas tree hydration, and to address the shortcomings of earlier designs has come up with a low water warning using an ultrasonic rangefinder. Where previous sensor attempts based on conductive probes succumbed to corrosion or dirt build-up, this one has no contact between sensor and water.

Behind the rangefinder is a CHIP board, whose software sends a text message to his phone when the water level gets a bit low. All the software is available in the linked GitHub page, so should you wish to make your tree safe from thirst, you too can give it a try.

SMS texts are a good way to alert a tree owner, but we quite like the sensor that used the tree lights instead.

Listening For Hand Gestures

November 1, 2017 by 15 Comments

[B. Aswinth Raj] wanted to control a VLC player with hand gestures. He turned to two common ultrasonic sensors and Python to do the job. There is also, of course, an Arduino. You can see a video of the results, below.

The Arduino code reads the distance from both sensors — one for the left hand and the other for the right. This allows the device to react to single hand gestures that get closer or further away from one sensor as well as gestures involving both hands. For example, raising your left hand and moving it closer or further away will adjust the volume. The right hand controls rewind and fast forward. Raising both hands will start or stop playback.

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Ultrasonic Array Gets Range Data Fast And Cheap

August 30, 2017 by 8 Comments

How’s your parallel parking? It’s a scenario that many drivers dread to the point of avoidance. But this 360° ultrasonic sensor will put even the most skilled driver to shame, at least those who pilot tiny remote-controlled cars.

Watch the video below a few times and you’ll see that within the limits of the test system, [Dimitris Platis]’ “SonicDisc” sensor does a pretty good job of nailing the parallel parking problem, a driving skill so rare that car companies have spent millions developing vehicles that do it for you. The essential task is good spatial relations, and that’s where SonicDisc comes in. A circular array of eight HC-SR04 ultrasonic sensors hitched to an ATmega328P, the SonicDisc takes advantage of interrupts to make reading the eight sensors as fast as possible. The array can take a complete set of readings every 10 milliseconds, which is fast enough to allow for averaging successive readings to filter out some of the noise that gets returned. Talking to the car’s microcontroller over I2C, the sensor provides a wealth of ranging data that lets the car quickly complete a parallel parking maneuver. And as a bonus, SonicDisc is both open source and cheap to build — about $10 a copy.

Rather use light to get your range data? There are some pretty cheap LIDAR units on the market these days.

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Hackaday Prize Entry: Sonic Glasses

August 28, 2017 by 11 Comments

This year, the Hackaday Prize is going to find the most innovative and interesting assistive technologies. Whether that’s refreshable Braille displays or reliable utensils for the disabled, the finalists for the Assistive Technologies portion of the Prize will be creating some of the most interesting tech out there.

For his entry into the Assistive Technology part of the Prize, [Pawit] is building binaural glasses for the blind. It’s difficult to navigate unknown environments without a sense of sight, and these SonicScape glasses turn cheap distance sensors into head-mounted sonar.

The glasses are built around a pair of ultrasonic distance sensors (the HC-SR-04, if you’re curious), mounted in a convenient 3D-printed enclosure that looks sufficiently like a pair of glasses to not draw too many glares. (Although maybe we’d print them in black to lower the contrast.) Of note in this project is the Bluetooth connectivity to eliminate wires and independent left and right audio channels. That last bit — being able to hear in left and right — is something we haven’t seen before in devices like this and aims to greatly increase the usability of such a device.

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Floating Ants And Drops Of Liquid With An Acoustic Levitator

August 24, 2017 by 9 Comments

Amuse your friends, amaze your enemies, and perplex ants and other insects, insofar as they are capable of perplexment. Accomplish all this and more with this handy dandy homebrew acoustic levitator.

Before anyone gets to thinking about using this technique to build a hoverboard that actually hovers, it’s best that you scale your expectations way, way down. Still, being able to float drops of liquid and small life forms is no mean feat, and looks like a ton of fun to boot. [Asier Marzo]’s Instructable’s post fulfills a promise he made when he first published results for what the popular press then breathlessly dubbed a “tractor beam,” which we covered back in January. This levitator clearly has roots in the earlier work, what with 3D-printed hemispherical sections bristling with ultrasonic transducers all wired in phase. A second section was added to create standing acoustic waves in the middle of the space, and as the video below shows, just about anything light enough and as least as cooperative as an ant can be manipulated in the Z-axis.

There’s plenty of room to expand on [Asier]’s design, and probably more practical applications than annoying bugs. Surface-mount devices are pretty tiny — perhaps an acoustic pick and place is possible?

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