Working.txt

Arduino Part Working Mechanism
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The device is turned on, wait for 5 second
Initialize SMS library
Then execute the following in an infinite loop
    if there's a new SMS
        try parsing it with Parser
        if he succeed, extract password and match it
        with auth-helper
        if that succeed, figure out what kind of message it is
        if it's a status request message:
            Populate parser variables and generate an sms
            give it to sms library
        if it's a status update message:
            Set hardware values from parsed values
            send back the new status just like we did with status request
        if it's a change phone no message
            simply update the phone number
            send new status to new number
        if it's a change password message
            simply update the password
            send new status back


Security Mechanism
------------------
The device needs a password to authenticate
If the password is forgotten, a button inside the device will reset
it to a default value.

Parser
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UPDATE: all \n are to be replaced by <space>

Recieve General Format:

-----------------
|$PASSWD CMD\n  |
|CMD BODY       |
-----------------

Send back General Format:
(after executing change ph.no/passwd)

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|$STATUS_CODE   |
|Human readable |
|description    |
-----------------

New status msg send to phone:

---------------------
|$STATUS_CODE DESC\n|
|ON Dev no.s\n      |
|OFF Dev no.s\n     |
|TEMP Temp_in_C C\n |
|WATERLVL Prcnt%\n  |
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Estimated Chars:
    1+3+1 =           5
    2+3+2(sp)+16+1 = 22
    5+2+3          = 10
    13             = 13
    Total          = 50
    Remaining chars for
STATUS_CODE: (possible values)
    Status Updated