In this project, a solution and prototype was developed for Mapiq that enables users in shared workspace environments to find a workspace, and increases the effective efficiency of existing resources through a social system. In shared workspace environments such as university libraries and an increasing number of offices (like clients of Mapiq), desks are allocated through the first-come first-serve method. This creates uncertainty with the users of these workspaces, as they are never sure where a workspace is available. The first part of the system is a method of reliably measuring a human presence at a desk. Knowing whether or not someone is sitting at a desk is the first step in collecting the information needed to show users a free workspace. The second part is the design of a set of interactions and rules that encourage people to provide the extra information that is needed. This extra information is needed because people tend to leave their belongings on a desk to claim it, even though they are not present, a bit like the behaviour that can be seen with pool chairs in holiday resorts. If a purely sensor based approach was used, there would exist large discrepancies between the information in Mapiq. These two parts come together in the design of the "Desktimer", a small device that is placed under each desk. This device allows users to make ad-hoc ‘reverse reservations‘. If a user provides an estimated time of absence, a desk will go into ‘temporarily free‘ mode, allowing other people to use the desk in the meantime. The solution was arrived at through a process of iteration and evaluation, with a final large scale user test to test the most important hypotheses that informed the design. The functional prototype was developed through a simultaneously performed iterative process, and culminated in a device that is capabable of all the designed user interactions.