A sensor apparatus 100 for an item of smart clothing houses sensor electronics comprising a position/orientation sensor 105, a temperature/humidity sensor, and a wireless communications interface 109, all of which are coupled to a processor 103. A battery 101 powers the processor 103. The processor 103 determines temperature/humidity based on signals from the temperature/humidity sensor and sends an alert via the wireless communications interface 109 if the temperature/humidity is above a threshold or if the rate of increase of temperature/humidity is above a threshold. If the battery charge level falls, or if an isolate signal is received via the wireless communication interface 109, the processor 103 disconnects some or all of the sensor electronics to run in a low power mode. The processor 103 may send alerts in the event of an acceleration greater than a threshold, or if the apparatus 100 has not changed position/orientation for some time. The apparatus 100 may be waterproof.
