The number of potential applications for wireless sensor networks is immense. These networks may consist of large numbers of low cost, low power, disposable sensor nodes that can be deployed inside or close to phenomena to be monitored. The nature of these networks necessitates specific design requirements, of which energy efficiency is paramount. The limited available energy of sensor nodes is mainly drained during communication and computational processing. An energy efficient routing protocol can limit the number of message transmissions and the computational complexity of finding routing paths. Many routing protocols have been proposed for wireless sensor networks. Most of them are computationally complex, require a large number of messages to be transmitted or require that sensor nodes possess certain hardware capabilities in order to function. The objective of this dissertation was to develop a Simple Energy Efficient Routing (SEER) protocol for wireless sensor networks that is computationally simple, reduces the number of transmitted messages and does not impose any hardware prerequisites. The new routing protocol, which was developed during this research, uses a flat network structure for scalability and source initiated communication along with event-driven reporting to reduce the number of message transmissions. Computational simplicity is achieved by using a simple method for routing path selection. The SEER protocol selects the next hop for a message by choosing a neighbour that has a smaller or equal hop count to the current node. If multiple neighbours satisfy this requirement, the neighbour with the highest remaining energy is chosen as the next hop. Each node in the network has a table containing the hop count and remaining energy of each of its neighbours. Periodic messages sent through the network update these neighbour tables. SEER uses a novel approach to select the next hop of a message during routing. The protocol increases the lifetime of the network dramatically, compared to other similar routing protocols. This improvement is directly related to the reduction in the number of transmissions made by each node. The simplicity of the protocol reduces the required computational processing compared to other protocols, and at the same time makes this one of the few available protocols that does not impose hardware requirements on nodes in order to function. / Dissertation (MEng (Computer Engineering))--University of Pretoria, 2007. / Electrical, Electronic and Computer Engineering / unrestricted