An example iPhone project to show how to detect frequency of captured microphone audio. This project illustrates this stackoverflow answer: https://stackoverflow.com/questions/11686625/get-hz-frequency-from-audio-stream-on-iphone/19966776#19966776
This project uses Apple's Accelerate.framework to perform CPU consuming digital signal processing.
- Generate a specific frequency using Audacity for example.
- Run the project, play the sound.
The main stuff that does FFT is inside FFTHelper.mm.