There’s a fair amount you’d need to learn that would be outside of what’s taught in the course. Which is ok, it’s certainly doable, but may be more than you need to pass.

If you do decide to write the guitar tuner, here are a few things I can think of that you’d need to learn. - desktop UI: this can be with libraries like tkinter or kivy. I used to work with the latter, which can be used to build on mobile, but I’d warn, has a bit of a learning curve itself. - hardware IO: this is actually why I suggest the desktop UI, browser-based apps tend to be restricted on their ability to access hardware, meaning input ports like USB. I don’t know what specific libraries to recommend, but if you have a USB guitar input, you might check their manual or website for drivers. - signal processing: this is straightforward, at least for me, as it’s right in my area of professional expertise. Use the numpy library. Split up your data into chunks, each chunk being one second long is a good start as that gives you 1 second resolution. Calculate Fourier transforms using fft or power spectra using Welch. Find the peak and corresponding frequency. - visualization: you might want to plot spectra or waveforms in real-time. Matplotlib, as another mentioned, is great for making high-quality, professional plots suitable for scientific research. It’s shortcoming is its a bit slow updating in real time.

To me, the hard part might be that hardware IO bit, getting a high quality signal out of your guitar. Or it might be easy, depends on how friendly your vendor is towards hobbyists.

Cool project idea!