We propose a method for accurately and precisely measuring the intrinsic latency of input devices and document measurements for 36 keyboards, mice and gamepads connected via USB. Our research shows that devices differ not only in average latency, but also in the distribution of their latencies, and that forced polling at 1000 Hz decreases latency for some but not all devices. Existing practices - measuring end-to-end latency as a proxy of input latency and reporting only mean values and standard deviations - hide these characteristic latency distributions caused by device intrinsics and polling rates. A probabilistic model of input device latency demonstrates these issues and matches our measurements. Thus, our work offers guidance for researchers, engineers, and hobbyists who want to measure the latency of input devices or select devices with low latency.

In the field of pedestrian navigation some systems use prominent identifying features, so called landmarks. Attributes of high-quality landmarks are recognizability, actuality, uniqueness and noticeability. One of the challenges of this kind of navigation systems is to collect and evaluate landmarks with consistent quality. The system we developed solves these struggles with a crowdsourcing approach. We combine this with gamification elements in order to reach many users and to assure long-term motivation. Our system shows images of existing landmarks to the player, which he is afterwards asked to assign to a map of the university. Depending on the distance of his guess to the real position the player earns points. The application strives to encourage users to upload and rate pictures of existing landmarks. A multiplayer mode which allows challenging other users keeps them involved. In contrast to other products, our system does not rely on localization via GPS. Another goal was to implement a self-running system with a minimal amount of dedicated administration needed. Therefore the users with the highest scores are rating the submitted content.