I have an old cell phone. I saw that the definition of your screen is very good and that dynamic images are easily created. I could turn it into an oscilloscope
Although there are applications that take advantage of the microphone to enter the signal, they are very poor in resources, as they only work with audio signals and their definition is not the best. In fact, this low definition would be a first impediment. But, the most difficult thing is to access the display hardware to work on it. The assembly is extremely compact, and it would be difficult to obtain the pin functions of the circuits involved in an adaptation work.
