Wireless Sensor and Actuator Networks for Lighting Energy ...

to its simplicity. Although coded with a different language, the integrity of the mote-
FVF algorithm remained intact.
The prototyping luminaire structure was equipped with the mote-based ballast
actuation module so as to dim the lights wirelessly. Furthermore, the experiment system
was made into a self-contained illuminance regulation system that maintained the
illuminance on the testbed at a specified value without the presence of a central
computer to coordinate the control actions. The mote integrated with the actuation
module was embedded with a simple rule-based control law, and it listened to the fused
readings from the cluster of mote sensors. Upon receiving a fused value from the sensor
cluster, the actuation mote calculated and performed the control action based on the
control law in order to maintain the testbed illuminance at the setpoint. Although no
extraneous computer was required in the experiment system, a computer was still
employed to intercept the readings from each sensor and the fused values for data
gathering purpose. The default setpoint of 500 lux was hard-coded in the actuation
mote, which could be changed in real-time by sending a management command to the
actuation module specifying a new setpoint from the computer.
Experiment results
The first experiment lasted over 17 hours to show that the system can sustain
long-term unattended operations. The luminaire structure was located in a research lab
without windows to introduce natural daylight perturbation. In order to evaluate the
system’s ability to regulate the desktop illuminance at the setpoint, the overhead
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