Abstract-We present TeaCP, a prototype toolkit for the evaluation and analysis of collection protocols in both simulation and experimental environments running on TinyOS. Our toolkit consists of a testing system, which runs a collection protocol of choice, and an optional SD card-based logging system, which stores the logs generated by the testing system. The SD card datalogger allows a wireless sensor network (WSN) to be deployed flexibly in various environments, especially where wired transfer of data is difficult. Using the saved logs, TeaCP evaluates a wide range of performance metrics, such as reliability, throughput, and delay. TeaCP further allows visualization of packet routes and the topology evolution of the network, under both static and dynamic conditions, even in the face of transient disconnections. Through simulation of an intra-car WSN and real lab experiments, we demonstrate the functionality of TeaCP for comparing the performance of two prominent collection protocols, the Collection Tree Protocol (CTP) and the Backpressure Collection Protocol (BCP). We also present the usage of TeaCP as a high level diagnosis tool, through which an inconsistency of the BCP implementation for the CC2420 radio chips is identified and resolved.Index Terms-Network and systems monitoring, wireless sensor networks, collection protocol, performance evaluation and visualization, opensource toolkit.