What sensor i will use in my project , i want to to make a project whenever the stand of the motor unstand the device will send a message to my cellphone


It's not clear exactly what you are doing or how far you have already got, but in principle, you will need an arduino board, a cell phone shield/device, something to measure the status of your system components (including motor), and a sketch to join it all together.
Post links to your design and components together with any code you have written, and maybe someone here can help you.