remote garage alarm with gprs/text warner

Other Hardware General Electronics
1

i think this is the right area so here we go
hey everyone im a n00b in these forum so let me introduce myself
my names josh and im doing and apprenticeship in electronics currently studying for a national certificate in electronics in the UK

now down to business:
i rent a garage and the door on it is the up and over type which are notorious for being easy to break into
iv got some hidden bolts for the bottom and a ground anchor to chain my speakers to but im looking at making an alarm that gose off when the door is opened without the door handle being turned.
but since the garage isn't exactly that close to me i don't check on it that regularly so if the alarm where to be triggered it would be good to know so that i can go check if the garage is ok and get my stuff out iff the door has been damaged. if i dont know then when the alarm eventually stops the thief can just come back and take my stuff lol
also iv got no mains in there so everything would have to be battery powered

my idea:
could i simply chop up a cheaper than chips phone and solder the buttons up to an ardruino and then program the ardruino to type out and send me a short message buy simply "pressing" the keys?
i could also then get a laptop battery or something similar and rig a a 5v regulator and low power cut off circuit that way i could send a signal to the arduino that the battery is flat and then the ardruno can press the buttons to send me a text telling me the battery is flat. then i will have about a week to change it befor the phone dies. the aurdrino can be put into sleep mode and woken up every 2 seconds for example to check if the door is ok and will use almost no power and i can run it on 9v or something for about a year or maybe solar pannles could help on this one? since a regulator, hone and charging circuit should consume less than 100ma that would be about 50ma at 12v meaing i would only need about 0.6w to keep it charged but then again solar pannles only work in the day and i would get some losses if i used a 12v lead acid.

suggestions and help needed! thanks in advance :smiley:

2

could i simply chop up a cheaper than chips phone and solder the buttons up to an ardruino and then program the ardruino to type out and send me a short message buy simply "pressing" the keys?

That's unnecessary. You can buy cellular modules that can be wired to your Arduino to give you that capability. Example: http://www.sparkfun.com/products/10138

3

thanks for your reply
that is 30 quid but i think its 30quid im happy to spend if it dose the job just like it shoould do
only problem is im currently not the best at coding
my only worry is to buy this module and then end up buried in code and serial transmission that i don't understand
i can turn lights on and off very well but thats about it so far i haven't really tried anything else
can someone tell me. is this going to be hard to learn? dosnet seem tooooo bad but im a bit dubouse

4

Quick q for the USA anyway--What wireless providers would sell you a "text/data-only" type of SIM card for such projects (say for something that sits around forever and rarely does any I/O but does it once in a while)?

5

you cant get text and data only
you can get data only for usb modems ect that's about it
im going to use giff gaff in the uk because there quite cheep and the credit never expires!