LEUVEN, Belgium Researchers at IMEC will develop a custom ultra-low power digital signal processor as part of work on a wireless sensor node for a variety of applications including a body-area network. The European research group has already developed wireless and sensor ASICs for the project.
The group's overall goal is to deliver a wireless sensor node that consumes 100 microwatts or less. The individual ASICs will consume less than 20 microwatts each.
IMEC is creating a custom instruction set for a body-area network DSP to enable an ultra low power part for the application. The group has already developed a prototype ASIC for the emerging 802.15.4a standard that can transmit up to 1 Mbit/second awhile consuming a single milliwatt, however the device would have higher power consumption in its generally unused receive mode.
The transmit power consumption "is an order of magnitude less than Bluetooth or Zigbee," said Bert Gyselinckx, a program director for wireless systems at IMEC.
Companies including National Semiconductor, NXP, Philips and Texas Instruments are taking part in the project, in part to gain access to the low power technology. "I'm pretty confident this wireless technology will make it to the consumer market, but it could take as long as five years," he said.
At an annual press meeting, IMEC demonstrated a health monitor using the current version of the sensor node which includes a low power ASIC for monitoring electrocardiogram signals. The system was based on a 20.5 x 25 mm sensor node generally using merchant silicon including a TI DSP.
The system used an algorithm running on a PC to determine an overall level of excitement based on readings of heart rate, skin conductance, temperature and breathing rate.
"Today we use [mainly] off-the-shelf components, but we are also developing low power components to make the system lower power and more wearable," said Gyselinckx. "We are taking this technology and equipping it with better algorithms and making it wearable and lower power," he added.
Researchers want to run at least part of the algorithm on the sensor node to further reduce power consumption and prolong battery life. They believe the monitor could be used in a handful of applications such as providing biofeedback for therapy, clinical research, e-learning or gaming.
One company already markets a $299 biofeedback system for gamers. Philips has articulated a concept of a consumer necklace that provides biofeedback.
The IMEC body-area network consists of two small wireless sensor nodes that communicate to a PC acting as a base station. One sensor node is integrated into a chest belt and the other is integrated in a wristband.