A BSN is a heterogeneous environment populated with different types of sensors. As such it needs a framework to abstract to applications the underlying sensor resources they need to get the information from. Such framework (a middleware), should allow applications to issue information requests with a set of requirements to be met. This would then be translated into sensor resource access( es) while trying to abide by the requirements. In this paper we describe an architecture proposal for such a middleware and an implementation overview of a first prototype. We focus on the first layer needed to provide an abstraction to the resources.