A free program for Android, by NETIGEN.
The Perfect Guitar Tuner app is a handy utility that will allow you to tune your guitar or any other musical instrument with ease. The app has three modes: Auto, Manual, and Play.
In the Auto mode, the tool will automatically tune the instrument based on the frequency of the sound that is captured by the microphone. In the Manual mode, you can manually choose the desired tone and the app will play the captured sound. Finally, in the Play mode, you can choose a sound and the app will play it back to you.
The Perfect Guitar Tuner app can tune a wide variety of musical instruments such as guitar, banjo, ukulele, violin, viola, and more.