Medical Applications of Wireless Sensor Networks: Who-Did-What - Application and Multidisciplinary Aspects of Wireless Sensor Networks - page 173

design of SecureComm messaging protocol which supports user-based decisions
for selection of security policies.

8.4.3.4 BikeNet

BikeNet is an extensible mobile sensing system, being developed through col-
laboration of Dartmouth College and Columbia University, for cyclist experi-
ence mapping leveraging opportunistic sensor networking principles and
techniques. It represents a multifaceted sensing system and explores personal,
bicycle, and environmental sensing using dynamically role-assigned bike area
networking [ 5 ].

Hardware

The BikeNet architecture includes

• Moteiv Tmote Invent sensor nodes

• Nokia N80 mobile phones

• PCs and servers

These devices are organized in three tiers: the mobile sensor tier , the sensor
access point (SAP) tier , and the back end server tier .
The mobile sensor tier incorporates a number of bicycle-mounted and human-
mounted Tmote Invent platforms. Tmote nodes constitute a BAN. Platform native
sensors in use are: a two axis accelerometer, a temperature sensor, a light sensor,
and a microphone. Other sensors additionally attached to the motes include: a
magnet-triggered reed relay for angular velocity of the wheel and pedal and dis-
tance measurements, a dual axis magneto-inductive sensor (Honeywell
HMC1052L) for measurement of direction and deviation with respect to Earth's
magnetic field, a Garmin Etrex 12 channel GPS unit for absolute time and loca-
tion measurements, a Telaire 7001 CO 2 /Temperature Monitor for CO 2 measure-
ments, an ArcherKit Biofeedback Monitor for measurement of the galvanic skin
response of the cyclist.
The SAP tier serves as gateway between the mobile sensor tier and the back end
server tier. SAPs can be static and mobile. The static ones are wired directly to the
Internet. In essence, static SAP is a Tmote Invent plugged into USB port of an
Aruba AP-70 IEEE 802.11a/b/g access point. The mobile SAP is implemented
using a Bluetooth enabled Nokia N80. Between its back end interface and the back
end servers SAP uses GPRS/GSM communication, in case of mobile SAP, and
TCP/IP communication, in case of static SAP.
The back end server tier includes power, high performance servers with large
storage capabilities.