over voltage and over temp detection and sending an sms to registrd phone.on shutdown sms as return relay turns it off
sensor lm35
gsm sim 900a
I'm pretty sure this has been done before. Have you googled the subject? In almost any design situation, try "Arduino xxxxx" and fill in the x's with the area of interest. You'll get a lot more help from this Forum if the readers feel you have exhausted every available avenue before posting here. Indeed, many will only respond if they see code that suggests you've tried to design/solve the problem.
You should get some ideas from Planning and Implementing a Program
Start off by writing a short program to read the temperature sensor and a separate short program to send an SMS message. Only bring them together when you have each of them working separately. Google should find you plenty of program examples for both parts.
...R