Callbuddy

Most smartphone cases are designed around one primary purpose: protecting the device. Callbuddy began with a broader question: could a phone case also fundamentally improve the way people carry, hold and use their smartphone?

The original Callbuddy concept was conceived by Ivan Peeters and developed primarily through Inventus. Instead of treating the strap as a simple accessory attached to a conventional case, Inventus developed an integrated mechanical interface that turns the case into a modular product platform.

At the heart of Callbuddy is a compact click mechanism that allows a removable strap to be securely connected to the phone case. The strap can be detached, repositioned or replaced, enabling users to adapt the case to different situations and personal preferences. The same interface also creates possibilities for additional accessories and future product extensions.

Creating this apparently simple user experience required an extensive product-development process.

The connection had to feel intuitive while remaining sufficiently secure during everyday use. It needed to withstand repeated attachment and removal without becoming loose, yet it also had to remain easy to operate. At the same time, the mechanism could not make the case unnecessarily thick, heavy or visually complex.

Inventus led the majority of this development process, including the underlying mechanical concept, product architecture, material selection, engineering, prototyping and functional testing.

Particular attention was given to the interaction between rigid and flexible materials. A structural base is required to provide strength and dimensional stability, while carefully designed flexible elements create the movement and locking action of the click mechanism. Even small variations in geometry, wall thickness, material hardness or manufacturing tolerances can significantly influence how the connection performs and feels.

Successive prototypes were therefore used to evaluate the mechanism under realistic conditions. Each iteration generated new insights into locking strength, flexibility, user comfort, durability and manufacturability. These insights were then incorporated into the next development cycle.

This combination of mechanical design and material engineering made it possible to integrate the click function into a compact and visually coherent consumer product.

Callbuddy has since evolved beyond the original idea of a protective smartphone case. It has become the foundation for a broader modular ecosystem in which straps and accessories can be connected through one recognisable interface.

The product illustrates an important Inventus principle: meaningful innovation does not always require creating an entirely new product category. It can also emerge by reconsidering an everyday object and introducing a technical principle that changes how people interact with it.

Callbuddy was conceived in Belgium, developed into a functioning product through Inventus and has already reached more than 1,000 users.

Invented by Ivan Peeters. Developed primarily through Inventus. Designed to turn an everyday smartphone case into a modular platform.