Design, development, and evaluation of a simple wireless sensor network for indoor microclimate monitoring

We describe the design and development of a wireless sensor network for monitoring the microclimate indoors. Such a network is useful for applications such as thermal comfort monitoring and artwork collections management. To simplify the design of the sensor node, we use an ASK transmitter and the ALOHA without retransmission protocol. This greatly simplifies the communication between the sensor node and its base station, aside from minimizing the total cost of the sensor node. We extend the range and reliability of transmissions by implementing error detecting and correcting codes. The sensor nodes are made power efficient by operating on low duty cycles. The optimal sampling rate of the sensor node was determined in order to maximize the battery life. To further minimize the power consumption of the sensor node, a simple threshold-based transmission algorithm was used. A forecast of the sensor node lifetime was made by determining its load profile and characterizing the actual batteries used through experiments. The performance of the sensor network in terms of transmission range and success rates was evaluated. The sensor network was successfully deployed in a museum as a tool in aid of preventive conservation.