Here is a basic list of some of the recommended sizes of controls and spacings between them, that can be a good starting point for sketching physical panels.
| Dimension | Minimum | Recommended |
|---|---|---|
| Button size | 8 mm | 12 mm |
| Knob diameter to rotate by using two fingers | 8 mm | 12 mm |
| Knob diameter to rotate by using single finger | 25 mm | 40 mm |
| Button spacing for tactile differentiation | 2 mm | 5 mm |
| Spacing between knobs | 12 mm | 20 mm |