In order to assess the viability of locations for proposed wave energy farms, and design optimal wave energy converters and wave farm layouts, wave farm developers will need knowledge of local wave regimes. Furthermore, with the increasing occurrence of extreme weather events, coupled with rising sea-levels as a results of climate change, local authorities will also require knowledge of wave regimes in order to design effective coastal protection measures. Most existing buoy measuring devices are expensive, and the aim of the work described herein is to develop a low-cost, self-powering buoy to measure wave conditions to meet the needs of both developers and local authorities. The proposed device, christened the Wave-activated Sensor Power Buoy (WASP), will comprise a floating body with a centre moonpool. The relative motion of the water level in the moonpool to the buoy will be used to drive a bidirectional turbine in the manner of an oscillating water column, which will be used in conjunction with a generator to recharge an on-board battery pack. The sea-state can be estimated from measurements of the variation in pressure within the air above the water column for a suitably calibrated buoy. Mathematical techniques to accurately estimate sea-sates including inverse transfer functions, neural networks and numerical estimators, each of which is currently the subject of further investigation. Calibration of the WASP will take place in the SmartBay test facility. Proof of concept testing in SmartBay, using an off-the-shelf buoy, is scheduled for late 2018.