Fosi VOL20 Multi-media Control Knob with RGB light

As a music enthusiast and gamer, I often found adjusting volume across different apps to be a hassle.  The inconsistency in volume levels and the inconvenience of using software controls or keyboard shortcuts led me to realize the need for a dedicated, easy-to-use volume knob.  Additionally, as a desktop setup enthusiast who values a clean and minimalist workspace, I wanted a wireless solution that would eliminate clutter and provide seamless control.

After discussing this idea with my team, we discovered that many people shared this need, especially when relaxing on a couch or bed. However, the market offered few high-quality wireless options - most existing products were wired and lacked the tactile and aesthetic appeal we desired.

We meticulously designed the VOL20 to address these needs.  The 65mm diameter was chosen to balance functionality and space efficiency, catering to various user preferences.  We focused on a minimalist design inspired by Apple's clean aesthetic, adding an RGB ambient light to complement any desk style.

One key feature is the intentional gap between the top cover and the light-guiding ring. While it might not appear seamless, this design choice enhances the knob’s tactile feel and ergonomics, creating a satisfying experience when adjusting the volume.

The VOL20 is more than just a volume knob—it's a product that combines functionality, design, and user-centric innovation to enhance your daily life.

This 3D mechanical analysis diagram illustrates the force distribution when we rotate the volume control knob with a single finger and explains how a slight tilt of the top cover makes the operation smoother.

1. Finger Force: The red arrow in the diagram represents the force applied by the finger. This force acts on the edge of the knob, pushing it to rotate around its central axis.

2. Tilt Direction: The blue arrow indicates the slight tilt direction of the knob’s top cover. Due to the top cover’s slight wobble (tilt), the change in tilt angle during rotation makes it easier to apply rotational force.

3. Resultant Force: The green arrow shows the resultant force direction, which is generated by the combined effect of the finger force and the tilt direction of the top cover. This resultant force aligns better with the knob’s rotation path, making the rotation feel more responsive and smoother.

The slight wobble (tilt) design allows the finger’s force to be distributed more naturally across the knob’s surface, reducing resistance during rotation. This design not only adheres to ergonomic principles but also makes single-finger rotation operations smoother and more natural.