Initial Phase
Our first prototype consisted of two rounded arrays, each with 36 16mm 40kHz transducers, creating a standing wave. The nodes are concentrated in the centre of the prototype and we were able to levitate up to 3 styrofoam balls along the centre axis. We were also able to control the movement of the styrofoam balls about 1cm along the centre axis (up-down movement).
However, we wanted to achieve 3-dimensional movement for our final product hence we had to change our design from a rounded array to a flat array. This is also to achieve a wider scope of movement since this initial design is a single axis levitator.
Prototype
We designed our flat array to be composed of 64 10mm 40kHz transducers. We chose to use 10mm instead of 16mm transducers as this would give us greater range of control. We also ordered custom PCB boards specifically designed for this flat array. Each transducer is connected to one pin, allowing us to individually control each transducer’s emitting frequency.
We wanted to create 4 identical flat arrays + PCB and arrange them in a 4-sided configuration (as seen in the picture above). The video (click on link!) shows how the 4-sided acoustic levitator works.
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Final Product
Due to problems with our transducers we discovered during troubleshooting, we decided to change our design from involving 4 arrays to only 2 arrays. This is because we had two different brands of transducers and 2 arrays were made using each brand. The 2 brands of transducers had slightly different specifications (specifically angle beam) hence they were not ideal to be used together. Additionally, during testing we discovered that the bottom array was not required if we had a surface for the ultrasonic sound waves emitted from the top to bounce off. Hence, our final product is a single sided acoustic levitator consisting of only 2 arrays.
This is a link to a video demonstrating how our final product works! IMG_3355.TRIM-1v7dcmx