Abstract: A structure sensor device monitors physical properties within a body of concrete, rock, soil or other structure. The structure sensor device can be embedded inside the body of the structure in use. The structure sensor device includes: a sealed housing; sensors for measuring physical properties within the body of structure, such as a temperature sensor and a moisture sensor; and a wireless transceiver for wirelessly communicating with a gateway device located outside of the body of structure. The wireless transceiver is configured for wirelessly communicating at frequencies of less than 1 GHz. There is a controller configured to obtain sensor data from the sensors, generate monitoring data using at least some of the sensor data, and cause the monitoring data to be transmitted to the gateway device using the wireless transceiver, at predetermined intervals.