Walk-Bot Is A Navigation Device For The Vision-Impaired

January 11, 2023 by Lewin Day 11 Comments

For the vision impaired, there are a wide variety of tools and techniques used to navigate around in the real world. Walk-bot is a device that aims to help with this task, using ultrasound to provide a greater sense of obstacles in one’s surroundings.

Is trigonometry the most useful high school maths out there? There’s an argument that says yes.

Created by [Nilay Roy Choudhury], the device is intended to be worn on the waist, and features two sets of ultrasonic sensors. One set is aimed straight ahead, while the other points upwards at an angle of 45 degrees. An infrared sensor then points downward at an angle of 45 degrees, aimed at the ground.

The distance readings from these sensors are then collated by a microcontroller, which uses trigonometry to determine the user’s actual distance to the object. When objects are closer than a given threshold, the device provides feedback to the user via a buzzer and a vibration motor. The combination of three sensors looking out at different angles helps capture a variety of obstacles, whether they be at head, chest, or knee height.

It’s unlikely that a complex electronic device would serve as a direct replacement for solutions like the tried-and-tested cane. However, that’s not to say there isn’t value in such tools, particularly when properly tested and designed to suit user’s needs.

We’ve seen some great projects regarding visual impairment before, like this rig that allows users to fly in a simulator. If you’ve been working on your own accessibility tools, don’t hesitate to drop us a line!

Mini Ultrasonic Levitation Kit Is An Exercise In Sound Minimalist Design

November 6, 2022 by Abe Connelly 20 Comments

For those that haven’t heard, ultrasonic levitation is a process by which two or more ultrasonic transducers are set opposite to each other and excited in such a way as to create a standing wave between them. The sound is, as the name implies, ultrasonic — so outside the range of human hearing — but strong enough so that the small, light objects can be positioned and held fixed in mid-air where there’s a pressure minimum in the standing wave. [Olimex] has created a small ultrasonic levitation kit that exemplifies this phenomena.

The kit itself is made using through-hole components, with an ATTiny85 as the core microcontroller to drive two TCT40-16T ultrasonic speakers, and a MAX232 ~~to provide a USB interface~~ drives the transducers (thanks to the folks in the comments for the correction). Two slotted rectangular PCB pieces that solder connect to the main board, provide a base so that the device stands upright when assembled. The whole device is powered through the USB connection, and the ultrasonic speakers output in the 40KHz range providing enough power to levitate small Styrofoam balls.

The project is, by design, an exercise in minimalism, providing a kit that can be easily assembled, and providing code that can be easily flashed onto the device, examined and modified. All the design files, including the bill of materials, KiCAD schematics, and source code are provided under an open source hardware license to allow for anyone wanting to know how such a project works, or to extend it themselves, ample opportunity. [Olimex] also has the kit for sale for those not wanting to source boards and parts themselves.

We’ve featured ultrasonic levitation devices before, from bare bones system driven by a NE555 to massive phased arrays.

Hackaday Prize 2022: Ultratower Is A Powerful Gardening Vertical

November 4, 2022 by Kristina Panos 29 Comments

The more people we have on this planet, the more food we need. Naturally, this extends to water, another precious resource that generally plays a part in farming and food production. And honestly, we’d probably all eat a little better if it were really easy to grow healthy things like spinach. Well, that excuse doesn’t work anymore, thanks to [J Gleyzes]’ Ultratower. It’s a simple-to-use hydroponic tower that uses recycled mist to water plants, ultimately saving water in the process.

The ‘ultra’ part is a function of the way mist is created. In this case, it’s done with three piezoelectric disks mounted under a tank in the top of the PVC tube. Stick up to twelve plants in the little cubbies, and their roots will grow down the inside, where they’ll receive a fine shower of water at your command. Water that runs off the roots collects in a small tank at the bottom, where a pump starts the process over again.

At first, [J Gleyzes] had trouble with the piezo disks — using 1.7MHz disks created too much heat, warming the water up to nearly 40°C (104°F). Since cooking the spinach prematurely would be bad, they experimented with other values, finally landing on 108KHz. Be sure to check out the video after the break.

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Hackaday Prize 2022: Drying Clothes With Ultrasound

September 4, 2022 by Lewin Day 29 Comments

Clothes dryers are great, and a key part of modern life, but they do use a lot of energy. [Mike Rigsby] decided to see if there was a more efficient method of drying clothes that could compete with resistive heating for efficiency. Thus, he started work on an ultrasonic clothes dryer.

In early testing, he found ultrasonic transducers could indeed blast droplets of moisture away from fabric, effectively drying it. However, unlike heat, the ultrasonic field doesn’t effectively permeate through a pile of clothes, nor can it readily be used with a spinning drum to dry many garments at once.

[Mike]’s current experiments are centered around using a basket-type system, with a bed of ultrasonic transducers at the bottom. The idea is that the basket will shake back and forth, agitating the load of clothing and allowing the different garments to effectively contact the transducers. It’s still a work in progress, but it’s an interesting approach to the problem. We’d love to see a comparison of the energy use of a full-scale build versus a regular dryer.

We’ve heard of the ultrasonic drying concept before, too, with the Department of Energy researching the matter. It could just be that we’ll all be using ultrasonic dryers in decades to come!

3D Printing With Sound, Directly

June 2, 2022 by Al Williams 16 Comments

Canadian researchers at Concordia University want to change how you do 3D printing. Instead of using light or thermal mechanisms, they propose using ultrasound-activated sonochemical reactions. Sounds wild? You can see a video about it below, or read the paper in Nature.

The idea is that sound causes bubbles of cavitation. This requires a focused ultrasonic beam which means you can actually print through items that are transparent to ultrasonic energy. Wherever the cavitation bubbles form, liquid polymer turns solid.

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2022 Sci-Fi Contest: A Hand-Following Robot, Powered By Arduino

April 13, 2022 by Lewin Day No comments

If there’s one thing audiences love in sci-fi, it’s a cute robot companion that follows the heroes around. If you want one of your own, starting with this build from [mircemk] could be just the ticket.

The build relies on the classic Arduino Uno microcontroller, which talks to a HC-SR04 ultrasonic sensor module and two infrared sensors in order to track a human target and follow it around. Drive is thanks to four DC gear motors, driven by a L293D motor driver, with a two-cell lithium battery providing power for everything onboard.

The robot works in a simple manner, following a hand placed in front of the robot’s sensors. First, the robot checks for the presence of an object in front using the ultrasonic sensor. If something is detected, the twin infrared sensors mounted left and right are used to guide the robot, following the hand.

It’s not a sophisticated algorithm, and it won’t really let your robot follow you down a crowded street. However, it’s a great project to learn on for beginners and could serve as a great entry into more advanced projects using face tracking or other techniques. Video after the break. Continue reading “2022 Sci-Fi Contest: A Hand-Following Robot, Powered By Arduino” →

Bend It Like (Sonar) Beacon With A Phased Array

February 23, 2022 by Matthew Carlson 7 Comments

Ultrasonic transducers are incredible, with them you can detect distances, as well as levitate and peer through objects. They can emit and receive ultrasonic soundwaves (typically above 18khz) and just like all waves, they can be steered via a phased array. [Bitluni] was trying to accurately measure distances but found the large field of view of the sensor was just too imprecise, so he made a phased array of transducers.

The inspiration came from a Hackaday Supercon talk from 2019 about phased arrays. [Bitluni] walks through an excellent explanation of how the array works with a bucket of water and his finger, as well as a separate simulation. By changing the phase offset of the different array members, the beam can effectively be steered as interference muffs the undesired waves. Using a set of solenoids, he created a test bench to validate his idea in a medium he could see; water. The solenoids fire a single pulse into the water creating a wave. You can see the wave move in the correct direction in the water, which validates the concept. A simple PCB sent off to a fab house with a stencil offers a surface to solder the transducers and drivers onto. An ESP32 drives the 8 PWM signals that go to the transmitters and reads in the single receiver via a small amplifier. Still not content to let the idea be unproven, he sets up the receiver on his CNC gantry and plots the signal strength at different points, yielding beautiful “heat maps.”

It sweeps a 60-degree field in front of it at around 1-3 frames per second. As you might imagine, turning sound wave reflections into distance fields is a somewhat noisy affair. He projects the sonar display on top of what we can see in the camera and it is fun to see the blobs line up in the correct spot.

We noticed he built quite a few boards, perhaps in the future, he will scale it up like this 100 transducer array? Video after the break.

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