How can I use internal microphone of my android smartphone to send signal to my app?
App must find frequency of sound using FFT method.
Perhaps
or use the magnifying glass in the upper right hand corner of this page and look for FFT .
Thank you. What if I would use microphone continuosly? I woul like to create an app that shows RPM (rotations per minute) of car engine.
ABG
4
You might have more luck searching this board for ELM327 and OBDII