B. Flow Chart For Gateway
The gateway is based on the ARM microcontroller which
processes the received data from the home units. First it
initialises the GSM for message transmission and LCD for
displaying numerical values. Timers initialise for the periodic
message. Serial port initialises for RF communication and
transmissions starts. Now a request is send to server to install
for the first time through GSM and wait for response. If
response received, it will send next frame to server and store
this value simultaneously. Now LCD displays the status of
GSM, door of meter and other connected devices at gateway.
The point A displays the door status. The gateway asks the
home meter units to send its status and meter readings once in
every 3 min. Then gateway sends a SMS requesting server to
update database with new status. If acknowledge is received
from server, the status frame is send to the server from
gateway via SMS and database gets updates with new data.
Again it checks for the status of connected devices and this
process will be continued forever.