Setting up IoT monitoring solutions requires a significant workforce for deployment and maintenance. This becomes particularly costly when a massive number of sensors are deployed. In this paper, we propose a generic solution based on energyautonomous LPWAN sensors deployed on the fly. On one side, we propose an efficient management strategy that adapts the transmission period of sensors in order to receive a chosen amount of information on each sensor cluster that emits similar information. Moreover, we develop a method that generates realtime estimates based on the sensor message history. After showing the relevance of our estimation method, we show that our sensor management method is efficient by comparing it to a baseline. Additionally, our tools are robust to the hazards occurring in the IoT: sensor arrivals and departures, noisy measuring in a highly variable environment, misplacement of sensors. Overall, this paper proposes a way to scale up IoT, breaking the deployment cost barrier and paving the way for universal and versatile monitoring solutions.