UpnaLab

I think in the latest version of the Arduino IDE, you need to compile it with -o3 or basically to optimize performance.

Sorted, thanks. It was just that the url was pasted twice

Sure, you can also make a single bowl with a larger radious of curvature. The modulation if you use the simplified arduino code (step 24) it is easy to add a counter that will make it only emit for 200 periods every 200 periods. The 200 Hz modulation works best. You can take the tractor beam instructables as a model for the bowl, I will look for the code with the modulation, kindly drop a private message to remind me.

Testing with a connectivity test of the multimeter. The mosfets are placed as close as possible to their pins. In any case, this can also be checked in the geber files. I should have released an schematic indicating which mosfets is in charge of which pins.

It may be hard to give it phase control. Otherwise just generate a 40kHz signal and that will do. Anyway, Arduinos Nanos are small and cost like 3$.

https://www.youtube.com/watch?v=h0Mh0bIv9Fk

Juanes there are several tutorials online on how to upload code to the MEGA, do not forget to make the changes in the software that are specified in the readme file.

no if it is enameled. It needs to be exposed and conductive.

there is a diagram up in the instructables

There is a diagram up in the instructables

Everything seems in order. Can you try with a small styrofoam sphere (1 or 2mm diameter), you can grab it from white packaging. Could you take a picture of how the levitator deforms the water surface? Best.

everything seems fine, try with an styrofoam particle of 1 or 2mm. You can grab some from white packaging. Best.

if you do not need to move the particle up/down, then any focused bowl that can be split in two halves will do the job. For 10mm you can also try the standing-wave levitator which can levitate denser things https://www.instructables.com/id/Acoustic-Levitator/ Best

Easiest way is getting another ARduino that will activate the D2-4, you can also used the simplified version that does not have up-down control. The program used for this one is a not very well adapted version from a phased-array controller https://ieeexplore.ieee.org/document/8094247/Best.

There is some technical info here: https://aip.scitation.org/doi/full/10.1063/1.4989995 Best

yeah, but you need a reflector opposite to it.