Use a circuit to a SMS message through mobile

Greatness to everyone
I am working on a project which consist a sensor connected to a circuit. This circuit will do many functions like opening gates and others. One of theses functions is "send message" which I hope you to help me about it.
I heard that I can use a relay to make a mobile to send that message. This method will use like the gold button to send it.
(circuit > relay > mobile)
I wouldn't like to deal with Arduino.
I am mechanical engineer student so my electric knowledge is poor ):
if there are suggestions websites for that show me.
I posted a picture.

Sorry, it's not that simple. Even if use relay contact(s) to replace the phone button(s), visualise sending a SMS from that phone ..... You will need a sequence of operations (mainly operating the buttons in a particular sequence) to send a SMS. So you are going to need a program to do the sequential operation.
You can write an "App" in Android / Symbian / Windows that runs in the phone to send a "pre defined" SMS by a single button operation (done by a relay contact); but with your background, you will need help from a Software Engineer to get things moving.
All the Best.