Abstract des Autors

The commercial market offers quite some time already personal electronic sports tools for control and monitoring of physical workouts. With these units, body measures like movement speed, tread rates, and heart rate are detected by tiny autonomous sensor units and their recordings are transmitted via RF for further processing to a central handheld device. Since a while, also smartphone apps can be used as control instance, if their ubiquitous host device supports one of the particular RF standards for coupling them to the sports sensors. During the last decade, two competing wireless standards have evolved for this sensor air link, which are called ANT+ and Bluetooth Low Energy. The key features of this remote communication technology determine the usability within the various scenarios in personal sports, for instance the question how many sensor devices can be operated closely to each other without interference. In this paper, the specified and advertised properties are analysed on base of the definition of these RF standards, and they are furthermore practically verified with experiments. In particular, measurements of power consumption are shown for the two different RF systems, since life time of sensor battery has relevant impact on convenience of daily use. Furthermore, practical observations of various spurious effects when using the two RF standards are reported here, which seriously bring the reliability and accuracy of such commercial devices into question.