Cool. Thanks Mick. I would never have thought to look for that.
The download screen information presented is:
The BOSS Tuner app brings BOSS’s trusted and world-renowned chromatic tuning technology to Android mobile devices. Available as a free download, the convenient app features the familiar look and intuitive display style of the best-selling TU-3 / TU-3W pedal tuner. Using the mic in your Android device, you can tune a guitar, bass and other instruments like violin, cello, brass, etc.
- Provides hands-free chromatic tuning for a variety of instruments
- Audible reference pitch function for tuning by ear
- Supports horizontal screen to enlarge meter view
- Tuning range: A#0 (29.14 Hz)--G8 (6,271.93 Hz)
- Tuning accuracy: +/- 1 cent
The "Audible reference pitch function for tuning by ear" can even be used as a signal generator if one doesn't have the bench equipment. (Adjustable over the range 110-880 Hz)
The app includes a built in operator's manual.