A robot's head is important both for directional sensors and, in human-directed robotics, as the single most visible interaction interface. However, designing a robot's head faces contradicting requirements when integrating powerful sensing with social expression. Furher, reactions of the general public show that current head designs often cause negative user reactions and distract from the functional capabilities. Therefore, this contribution presents a novel anthropomorphic robot head called "Flobi", which combines state-of-the-art sensing functionality with an exterior that elicits a sympathetic emotional response. It can display primary and secondary emotions in a human-like way, to enable intuitive human-robotinteraction. To facilitate further research on facial appearance, the exterior is fully modular and replaceable. While current state-of-the-art still requires trade-offs when integrating sensing and social expression, Flobi has been designed to enable serv...