The application identifies tones in the range of small, single-dashed and double-dashed octaves. In the MIDI directory, this is the C3-C6 range. The tuner tolerates quarter-tone deviations from the nominal frequency. The screen shows eight tones of one octave. The octave ranges are set automatically according to the pitch of the tone that just sounded or last sounded. The current range is indicated by a header icon on the right. You can use two screens, flipped horizontally, to display tones:
Basic screen - Body scale
The tones are identified by a moving ruler, changing their color according to the height reached: the tones of the quinta-chord are red, the other tones are blue, the semitones are black. In addition, pitch is displayed by hand movements in sign language.
Screen 2 - music outline with tones written in a single dashed octave. The range change is recorded by a key change (tenor, octave).

The colored tone markers are also touch buttons (right side) that play the tones of the current range. The sound strength must be adjusted in Settings-Sounds-Media.
The use of a voice tuner in music education is described in the articles in the Music Education series on the FEP Methodological Portal website.