Dynamic Timed Energy Efficient and Data Collision Free MAC Protocol for Wireless Sensor Networks This article proposes a new data collision free medium access control protocol for wireless sensor networks in automation environments based on Time Division Multiple Access (TDMA) with duty cycling, which presents less energy consumption than the S-MAC protocol while maintain high data throughput. The new protocol employs single channel and a carrier sense approach. Simulation results are presented and show how the new proposal outperforms the S-MAC protocol.