The latest generation of the Cyberjacket is powered by the gumstix computing platform. Based on the Intel XScale processor, the gusmtix is a single-board computer offering 4 serial communication ports, a USB client port, and a standard memory card slot. Wireless communication is provided by an optional onboard Bluetooth module, or through a Wifi expansion board. In addition to the range of other available expansion boards, including Audio, GPS, and Robotics modules, we have developed an interface board which allows the gumstix to be connected directly to our 8-wire bus. The 8-wire bus, which replaces the “nine-wire bus” used in previous versions of the Cyberjacket, forms the backbone of our wearable framework. The bus delivers power throughout the Cyberjacket and includes two serial communication lines, one at RS-232 level and one at TTL-level. The RS-232 lines allow a single device (typically an off-the-shelf device) to be connected to the framework and to communicate with the gumstix computer. The TTL lines allow any number of devices to be connected simultaneously, with arbitration handled at the application level. We have developed a number of devices for the 8-wire bus, including a 3D compass, a high-performance 3-axis accelerometer, and a GSR sensor. A general purpose sensor board is also available, allowing prototype sensors to be developed and built quickly. The system is powered by a small, lightweight 3.7v rechargeable lithium polymer battery. A typical configuration, consisting of a single device and the gumstix itself, lasts up to 6 hours on a single charge. Legacy devices, designed originally for the 9-wire bus, can also be connected via an adapter board. The adapter board handles power regulation and signal level shifting. |