The Cyberjacket

The Wearable is a plug and play wearable system. The system communicates with the environment using 802.11 and uses sound or a handheld screen to interface with the user.

The Wearable consists of a backbone (usually embedded in a jacket), sensors, a battery and a small mobile computer system. The backbone is a ribbon cable, called the “Nine wire bus”. This bus carries three serial lines, power and a contention line. Two of the three serial lines operate at RS-232 level, and use a standard RS-232 protocol with one transmit and one receive wire. These lines can be used by dedicated devices by using a standard RS-232 connector. The third bus operates at TTL level, and is shared between any number of sensors (we have tried 20 sensors). The transmit wire of this bus is used by the processor to poll one or more sensors, the receive wire is shared so that any sensor can post an answer. The contention line can be used to prevent multiple sensors from posting results at the same time. This bus is dedicated to low-bandwidth devices.

Each jacket will have at least two units: one or more batteries, connected to the bus in order to power all units (the bus carries unregulated power at between 7 and 14 volts), and a processing unit. At present we use ADS-Bitsies for processing data. The Bitsy is powered by a StrongARM, and has one PCMCIA slot that we use for 802.11. It has 32 Mbytes of ram and runs embedded Linux. We run software on the system to manage events and data streams, or to interface to the GRID. (To be added: links to the three infrastructure entries?)

We have developed several sensors on the bus, including accelerometers, compasses, ultrasonics positioning, ECG, SpO2, temperature, GPS, and we are working on a Gyro. The sensors are ‘plug-and-play’ in that they can be easily connected anywhere on the clothing, by clipping a connector onto the bus. The accelerometer can be hip mounted (to sense activity), arm mounted (for gesture recognition, or tilt recognition) or front/back mounted (for sensing steps and dead reckoning). The compass can be shoulder mounted (for body direction), arm mounted (for pointing), or head mounted (for generating stereo sound). The GPS is typically on the shoulder, the ECG needs three electrodes on chest and back, and the SpO2 oxygen saturation sensor has a finger clip.