example.kv

<Main>
GridLayout:
    pos: root.pos
    size: root.size
    cols: 3
    spacing: 100
    padding: 50

    Knob:
        min:4
        max:5
        size: 200, 200
        value: 0
        show_marker: True
        knobimg_source: "img/knob_metal.png"
        show_marker: False

    Knob:
        size: 200, 200
        value: 0
        show_marker: True
        knobimg_source: "img/knob_metal.png"
        marker_img: "img/bline.png"
        markeroff_color: 0.3, 0.3, .3, 1

    Knob:
        size: 200, 200
        value: 0
        show_marker: True
        knobimg_source: ""
        knobimg_color: 0, 0, 0, 0
        marker_img: "img/bline.png"
        markeroff_color: 0, 0, 0, 0
        marker_inner_color: 0, 0, 0, 1

    Knob:
        size: 200, 200
        value: 0
        show_marker: True
        knobimg_source: "img/knob_metal.png"
        marker_img: "img/bline.png"
        markeroff_color: 0.0, 0.0, .0, 1
        knobimg_size: 0.7

    Knob:
        size: 200, 200
        step: 25
        value: 10
        show_marker: True
        knobimg_source: "img/knob_metal.png"
        marker_img: "img/bline2.png"
        markeroff_img: "img/bline2_off.png"
        markeroff_color: 0.3, 0.3, .3, 1
        marker_ahead: 6
        knobimg_size: 0.8
        marker_startangle: 6

    Knob:
        size: 200, 200
        value: 0
        knobimg_source: "img/knob_black.png"
        markeroff_color: 0.0, 0.0, .0, 1
        knobimg_size: 0.9
        marker_img: "img/bline3.png"