Making an Acoustic Levitator or Ultrasonic Levitation

So, I wanted to try something cool with my ultrasonic sensors. I've already done projects like obstacle-avoiding cars and water level indicators before, but this time I was after something different. Then, I remembered reading about acoustic levitation in a research paper a while ago. It sounded fascinating, and it turns out I could make my own using the ultrasonic sensors I had – just needed a few more.

I started small, playing around with two sensors, then ten, and eventually ended up with a total of 20. Here's the lowdown on how this acoustic levitator thing works:

These ultrasonic sensors make high-pitched sound waves. By controlling these waves just right, they create a special pattern that looks like hills and valleys. I cleverly placed 10 of these thingies on top and 10 on the bottom. This setup creates a stable space where things can actually float!

In the upcoming guide, I'll walk you through each step, from taking apart the ultrasonic sensors to testing our final floating creation. We'll check which way the tiny speakers inside the sensors should face, set up the electronic part using an Arduino, write some simple code, connect everything with wires, print out some 3D parts, and finally, put it all together. Let's make magic happen with our acoustic levitator!

List of materials needed :

Arduino Uno

L293D motor driver

18 ultrasonic sensors

Soldering iron

Hot glue gun

3D printer

Some Wires

12V power supply

12V male and female jacks

Multimeter

In the initial phase of crafting an acoustic levitator using ultrasonic sensors, the process begins by carefully disassembling the sensor modules to extract the crucial components known as "transducers." Begin by obtaining an ultrasonic sensor, resembling a small robotic eye. Heat up your soldering iron and use the warmed-up soldering iron to delicately remove the sensors, ensuring they remain undamaged. A helpful tip for this task involves applying firm pressure to the terminals of the transducers, guiding them out from the other side.

As you extract the two components from the sensor module, you'll uncover one transducer and one receiver. Despite their similar appearance, they serve distinct purposes. Our focus for this project lies solely on the transducers, responsible for generating sound waves, not receiving or sensing them. Typically, transducers bear a 'T' marking on their back (as illustrated in the attached image), while receivers remain unmarked or may have a simple white dot. To ensure accuracy, marking polarity becomes imperative, and here's where the multimeter steps in. Don't rely on manufacturer markings; use the multimeter to confirm polarity. For a straightforward guide, I'll provide a link to a YouTube video explaining this process.

If you use more than two transuders, you have to connect them parallel to each other.

Connect your Arduino Uno to your computer and open the Arduino IDE. Next, open the attached file in the Arduino IDE, choose the correct port, and click the upload button to load the code onto your Arduino.

Placing the Styrofoam balls precisely in the center isn't a breeze with just your hands. To make things easier, you'll need a tool with a net that lets soundwaves through and can hold the Styrofoam balls securely. Lucky for us, we can repurpose one of the receivers we set aside earlier. With caution, open it up to retrieve its metal net. I fashioned something like a spoon using the net and a plastic refill from a pen, as shown in the picture.

Remember, the metal you cut from the receiver can be sharp, so handle it with care to avoid any accidental cuts on your skin. Safety first!

Now that you've got everything you need and your Arduino is all set, how about giving it a test run with just two sensors? Grab two transducers and attach them to something about 2-3cm apart. Place some tiny objects, like Styrofoam balls, in between to see if everything's working smoothly. In my initial testing, I started with two transducers, then bumped it up to ten for a prototype. However, the it didn't quite deliver much because the Soundwave were not focusing at the center as I placed the transducers on a flat surface and not a curved one. So, I took the plunge and designed a 3D model on Onshape, which worked like a charm for the final project. Testing it out with a smaller setup first can save you some trouble down the road!

Now enough prototyping... You'll need a solid design to hold 18 transducers at in such a way that they all focus at the center. So, download the 3d file that I've attached and print it on a 3d printer...

Now, for the final touch – place all 9 transducers on the top part and another 9 on the bottom of your model. Make sure each one fits snugly in its designated groove, and you should see two terminals sticking out on the other side. Pay attention to the direction they're facing. Remember, they have a positive and negative side. Connect them all together, ensuring they're all connected in parallel. And then connect them to the motor driver.This completes the circuit, and you're all set for the magic of acoustic levitation!

Now that your Acoustic Levitator is ready to roll, feel free to tinker with it! You can play around with different frequencies, tweak the code, or even swap Styrofoam for other small objects like tiny ants or water droplets. Experiment with adjusting the model's height – there are plenty of possibilities and a lot to explore. Interestingly, some folks have used this technology to create a real 3D hologram or display. If you're curious about that, check out the attached video from one of my favorite YouTube channels. It's a world of possibilities waiting for you!