The main goal in wireless sensor networking remains the reduction of the network lifecycle and the enhancement of its reliability, keeping decent performances in terms of throughput and latency. Given the increasing interest of the research community on wireless network coding (NC), we think such challenges can be tackled using its innovative concepts, especially in the case of many-to-one communications where network coding has shown promising theoretical results. Yet, without a thoughtful adaptation to WSNs, the benefits of NC for sensor networking prove to be too "greedy" and impractical. In this paper, we propose index-coding, a simple and effective packet coding scheme that enhances significantly many-to-one communications in ZigBee sensor networks. Index-coding uses smart bit-shifting operations in order to encode short messages from a set of sensors to a sink using fewer transmissions. Our implementation in a real ZigBee testbed shows substantial enhancement of network performances and resiliency.