PDIEC/TR 63071:2016 IECTR63071:2016IEC2016 - 6 - Peltier elements, cells， kinetic devices, chemical battery cells, MEMS devices and conventionalmotorsusedasgenerators. This document does not mention these energy-harvesting methods and devices, because of concerns with respect to interoperability and measurement methods of the energy-harvesting device. 5 Use case 5.1 General Any wearable device is the object of a power-supplying system.The existing major power Wearable devices need to work continuously as standalone and autonomous devices that require energy-harvesting power-supplying devices in order to be independent devices or systems. Typical use cases are: watch,eyeglasses,earphones and sensor-type wearable devices that require power- supplying devices, power-supplying devices that are part of elements of wearable devices, standalone power-supplying devices with wired or wireless connections to wearable devices, garment ortextile-type power-supplying devices with surface or membrane connection. 5.2 Use case examples 5.2.1 Generator in shoes How to connect, transmit and control, as illustrated in Figure 3, could be the subject of standardization. Piezo electric transducer - MEMS generator - Legacy generator motor with mechanism IEC Figure3-Generator inshoe 5.2.2 Animal tracking For animals,wearable devices,as illustrated in Figure 4, can be used for research purposes for their life and support. In this case, the generator is included in the wearable device becauseanimalscannottakecareofadevice. PDIEC/TR63071:2016 - 10 - IECTR63071:2016IEC2016 JEC Figure 4-Animal use 6 Interface Interfacespecificationfor information,control and powertransmission shouldbe standardized An existing standard is IEC 63002 that specifies an interoperability method for external power supplies. It is desirable to standardise connectors, cables and other physical structures, however standardization activities and use of standards depends on the market considerations and product applications.USB specified in IEC62680-1-1,IEC 62680-1-3and IEC 62680-2-2 are widely used standards for power transfer,and its control, information,connectors and cables can be suitable for various wearable devices. Based on small connector size, ease-of-use and flexibility, the USB Type-C T will play a major role in wearable devices. Wearable devices should be able to use many kinds of energy-harvesting devices. The items that should be standardized are: power control protocol and format, informationonpowerdevicesandtheirpowercharacteristics and information on clientdevices and theirpower characteristics. 7 Measurement method To connect any energy harvesting device to any wearable device, a standard is required.Also. the measurement method is required. The major characteristics of energy-harvesting devices Items of study are: power generation measurement: average power, intermittent power, powerdelivery schedule, power generation characteristics: voltage,current, power; power duration and fluctuation: short term, long term; lifetime: PDIEC/TR 63071:2016 IECTR63071:2016IEC2016 - 11 - in various environments; power efficiency: invarious environments