4.5. *EVENT MACHINE
the logical operators named above like it was done on the previous
example. Having this is mind different triggers may be created to
accomplish tasks like:
•
Sense a button press to send the current unit’s location to
different destinations, including a supervisor’s cellular phone
(through a SMS).
Have the unit make a voice call is also possible. This will make
the unit’s audio available to a predefined phone number when-
ever the user presses the button.
•
Speed limit monitoring which includes a time condition (sec-
onds) and an audible advisory (using the buzzer) that gives the
driver a chance to slow down before the actual speed violation
is reported.
•
Generate an alarm report whenever the primary power source
(mini-USB port)is disconnected.
•
Generate a report when the unit travels out of a predefined
polygonal region.
•
Generate a report when the unit passes a circular check point.
•
Sense and report the battery level status.
•
Use different reporting criteria according to the time of the day.
•
Generate a reconnection message to a TCP server whenever the
socket gets reconnected.
•
Generate a distance report whenever the vehicle’s traveled dis-
tance reaches a predefined threshold.
•
Use the communication channels available to the unit on a cost
effective way as they start failing: You can enable the unit
to always send its report via GPRS and only use SMSs when
GPRS goes down, finally if all GSM goes down too you can
attach another type of last option communication media like a
satellital modem to the unit’s serial port and tell the unit only
to use it when both GPRS and GSM are down. This gives a
full communication coverage at a cost effective schema.
•
Reduce a report frequency when the unit starts roaming on
GSM.
•
Create an intelligent
Time and Distance
report which auto-
matically increases the reporting criteria to a top as the vehicle
travels fast and decreases it to a minimum when the vehicle
travels at low or zero speeds.
68
