Image Processing Reference
In-Depth Information
Sensor platform
Processing unit
Power source
Communication
interface
FIGURE .
Sensor node components.
part of. The level of intelligence in the node strongly depends on the type of informa-
tion that is gathered by its sensors and by the way in which the network operates. The
sensed information is usually preprocessed to reduce the amount of data to be transmit-
ted via the wireless interface. The processing unit also has to execute some networking
protocols in order to forward the results of the sensing operation through the network to
the requesting user.
•
Communication interface
: his is the link of each node to the sensor network itself. he
focus relies on a wireless communication link, in particular on the radio communication,
although visible or infrared light, ultrasound, etc. means of communications have already
been used []. The used radio transceivers can usually function in simplex mode only,
and can be completely turned of, in order to save energy. One of the important aspects
of communication interfaces is that receiving information also consumes energy (in the
case of the current off-the-shelf radio transceivers, the sending and receiving operations
consume similar amounts of energy) so the assumption that a radio can have its receiver
on always does not hold.
•
Power source
: Due to the application areas of the sensor networks, autonomy is an impor-
tant issue. Sensor nodes are usually equipped with a power supply in the form of one or
more batteries. Current practices focus on reducing the energy consumption by using
low power hardware components and advanced networking and data management algo-
rithms. he usage of energy scavenging techniques (converting solar energy, vibrations,
temperature gradients, etc. into electrical power) makes it possible for the sensor nodes
to be self-powered. No matter which form of power source is used, energy is still a scarce
resource and a series of trade-offs will be employed during the design phase to minimize
its usage.
Sensor networks are usually heterogeneous from the point of view of the types of nodes deployed.
Moreover, whether or not any specific sensor node can be considered as being part of the network
