Today wireless sensor networks gain more and more relevance in measuring and recording of various physical or chemical parameters. For an independent a flexible operation all sensor nodes are equipped with batteries. All sensor nodes together are building a self-sustaining wireless network and directing all measured data via an on-demand routing algorithm to the base station. A source driven, data centric on-demand routing protocol was developed  for an efficient transmission of data sets via the network in direction of the base station. The routing protocol is based on the local attractiveness of each sensor node where for the next hop the neighboring node with the highest attractiveness will be chosen. The attractiveness of each node is calculated from several parameters like the distance to the base station, the actual energy etc. All data sets are transmitted via multiple hops in direction of increasing attractiveness where the base station is set to the highest value. The base station collects all data sets and enables a transmission via a mobile data connection (3G) to a server. By a smartphone the data sets can be easily accessed and displayed.
Posnicek, T., Kellner, K., & Brandl, M. (2014). Wireless sensor network for environmental monitoring with 3G connectivity. In Procedia Engineering (Vol. 87, pp. 524–527). Elsevier Ltd. https://doi.org/10.1016/j.proeng.2014.11.539