The number of applications that use industrial, scientific and medical (ISM) radio bands increase every day, creating interference problem for the wireless sensor networks (WSN) that generally operate on these bands. Cognitive radio sensor network (CRSN) has been proposed as a promising solution to this problem. However, since sensor nodes are energy constrained devices energy efficient spectrum sensing methods are needed for CRSN. To address this need, we propose a novel cooperative coarse sensing scheme for CRSN (CC4C). CC4C is based on sequential sensing, thus, it is simple and fast. Simulation results show that CC4C incurs less sensing delay and provides significant energy conservation compared to energy detection based coarse sensing schemes, and single stage sensing schemes where no coarse sensing is performed.