First, I would like to thank YouTuberr Mean Gene Hacks because it was thanks to his video that I discovered this concept (watch the video!) :

Even my implementation is only a slightly improved version of his, as I used his functional diagram and circuit as a basis for creating my own.

Here is the block diagram :

We receive the audio signal from a Bluetooth module, which we amplify and connect to an ADC pin on the RP2040. Then, using code, we modulate this signal and finally amplify the modulated signal to drive the transducer array.

Those are the component i am going to use :

Why i chose these components :

- Audio signal: using an MH-M18 bluetooth module makes the device more convenient to use than a conventional stereo jack.

- Preamplifier: I chose the MCP6022, an overall better operational amplifier for better audio quality (rail-to-rail means we will have much less audio clipping, and it also produces less noise than the LM358).

- uC: the RP2040 has a faster clock speed than the STM32F103C8T6, which allows for a higher sampling rate and better audio resolution, as it is possible to achieve higher resolution for a 40 kHz PWM thanks to the faster clock, but this is primarily a personal choice. using the rp2040-zero is much more practical in my opinion.

-Amplifier: The IXDN614PI has a much higher peak current and supply voltage than the TC4427A, which means we can drive more transducers at a much higher volume.

-Transducer: The TCT40-16T is sufficient for our application.

Overall, I am trying to achieve better performance with the same configuration as in the video.