The Bumblebee: UW Lab Creates Tiny and Energy Efficient Wireless Sensor

In the world of wireless sensors, size matters—and for many applications, the tinier the better. On a quest for the ultra-small and lightweight, Assistant Professor Brian Otis and his electrical engineering research team are pushing sensor technology into new frontiers.

Otis’ team has designed a low-power sensor called the Bumblebee that is four times more energy efficient than existing radio circuits, and the noise efficiency of the integrated bio-signal amplifiers approaches theoretical limits. UW researchers are already using the Bumblebee sensors to monitor insect behavior such as moth flight. The circuit has also been used by researchers at the UW and beyond to record data from mice, rats, humans, and monkeys. Other applications include both implantable and non-invasive monitoring of neural and muscular signals in mammals.

Bumblebee Specifications:

  • low-power 0.3g sensor containing roughly 100,000 transistors in each chip
  • four times more energy efficient than existing radio circuits
  • noise efficiency of the integrated bio-signal amplifiers approaches theoretical limits
  • can continuously transmit data over 10 meters for about three days on one 0.17g battery

As the technology approaches commercialization, it is sure to set off buzzing in the wireless device sector. The UW’s Center for Commercialization (C4C) is teaming with Otis to develop intellectual property strategy, provisional patent applications, and market strategies. One early application could offer a new approach to therapy for people with movement disorders caused by cerebral palsy, stroke, and traumatic brain injury.

A Wireless Way to Improve the Rehabilitation Experience

A key advantage of the Bumblebee sensor is that it can be taped to a person’s skin or embedded in a cloth sleeve to record surface electromyography (EMG) signals and even intent to move a muscle in a person who has little or no control over the movement itself.

This capability prompted two UW Rehabilitation faculty members, Associate Professor Sally Westcott McCoy, a physical therapist, and Assistant Professor Chet Moritz, a neurophysiologist, to collaborate with Otis to develop more flexible and effective EMG monitoring and exercise technology. They created a wireless system that frees the user from being tethered to a clinic workstation while doing therapy exercises. Instead, the sensors communicate through the airwaves to the user’s PC or other data logger so that muscle use during daily activity can be recorded and exercises can be recorded. This low-cost and unobtrusive system could be available for use in the home, so the patient would have more opportunities to practice exercises.

“It’s a pretty amazing process,” Otis said. “These extremely low-power sensors can transmit raw EMG data and detect muscle activity before movement begins. A therapist will even be able to monitor the therapy exercises remotely and adjust the system to reinforce the desired muscle activity.”

“The children and families who have tried the system really liked it,” McCoy said. They all want to participate in the next testing phase, and news about it is spreading through the grapevine. We’ve been flooded with calls from parents.”

From Laboratory to Market to Next Big Technology Wave

C4C has provided $44,000 in commercialization gap funding to support the team through the next critical stages of prototyping and testing the wireless bio-sensors and the software. They hope to have a set of ten devices ready for in-home deployment and testing by early 2011.

“Working with C4C has been a great experience. The staff have put an amazing amount of time into understanding the technology and helping with the entrepreneurial side,” Otis said. “It’s exciting to do research, but at some point you want to make a tangible impact. Starting a company and making a device to improve the health and well-being of many people is the perfect kind of impact.”

Staff in C4C’s New Ventures unit and entrepreneur-in-residence Ken Myer have been working with the team to explore business models, partnering options, and how and when to pursue essential venture funding. Beyond the therapeutic application, Myer sees even wider potential for next-generation Bumblebee sensors.

“We are just at the beginning of the next big technology wave—a revolution in wireless sensor networks. As the technology becomes cheaper, sensors will be embedded everywhere and we can’t even begin to imagine all the applications,” Myer said.  “Brian = projects. He is wisely gathering his facts and thinking about all the different ways he could take this technology and move it forward.”