With the DES testbed (Distributed Embedded Systems) we aspire to create a hybrid wireless testbed setup for long-term observations. In a first setup phase at least 50 wireless mesh routers equipped with three or more IEEE 802.11b/g NICs and an equal amount of wireless sensor nodes will be deployed. 100 nodes are planned in the final setup phase. This will enable us do experiments using non-simplistic topologies. The continuous runtime of single experiments is targeted at up to several months. The DES testbed is an essential part of further ongoing projects at Freie Universität Berlin such as OPNEX and WISEBED.