VitalMote Hardware

electronic patient triage tags, wireless vital signs sensors, and location sensors

Jon Sharp, Tia Gao

VitalMote is wearable device that is worn on the patient’s wrist or neck for continuous patient monitoring and tracking.   It monitors patients triage status, vital signs, and location in both indoor and outdoor environments.  VitalMote devices connects to a base station over an ad-hoc mesh network.  The base station forwards the information to a central station.  VitalMote also has onboard memory for storing the patient medical record.

VitalMote is built on top of a zigbee transceiver platform, commonly known as a Mote.  The transmission uses the TinyOS Active Messages protocol, which is based on the IEEE 802.15.4 standard.  The mote was originally developed at the University of California Berkeley in the late 1990’s.  Since then, it has gained significant interest from academia and industry for its ability to provide low-power, cost-effective, reliable wireless networks for monitoring applications.  It has a single-chip radio, with a maximum data rate of 76.8 kbps and practical indoor range of approximately 20–30 m.  Our VitalMotes use the MicaZ platform (Crossbow Technology) and the TelosSky platform (MoteIV Corporation). 

Our system is designed to require little setup time.A medic carries many VitalMote packages and distributes them to the patients. When the patient is first triaged, the medic straps the VitalMote to the patient, places the finger sensor on the patient’s finger, and sets the electronic triage tag.A wireless blood pressure cuff and EKG chest pad are an optional modules.The medic may use those on patients who need the additional level of monitoring. The mote automatically starts transmitting data to a base station.

With the triage tag and pulse, the pulse and oxygenation reported every second, the GPS location reported every 5 minutes The blood pressure sensor is the most power hungry peripheral, and when it is not used, the battery life of the overall device increases to 1-2 days.  The blood pressure cuff has the battery lifetime of approximately 6 hours when it reports readings every 15 seconds.

VitalMote technology is developed in collaboration with the CodeBlue project at Harvard University.  CodeBlue is a distributed wireless sensor network for sensing and transmitting vital signs and geolocation data.