The keybord of a piano is shown as graph horizontal axis and it shows pitch of your voice in range of 4 octorve.
You can use this app as voice tuner and check your voice pitch and range.
(1) Tap the START button and utter.
(2) Application shows your voice's pitch.
(3) Tap the STOP button to stop the measurement.
The author verifies the operation of this application in auther's android terminal, but the author does not assume any responsibility for damage of the user caused by using this application.
Please use at your own risk.