sometimes you wanna do something yourself and just for fun! I appretiate that.
If you've got the sensors and know the outputs, connect them to comparators. Each comparator has a reference voltage that guarantee a "ONE" output if a sensor feels something. Then "OR" the three signal and give it to a port of a microprocessor that has been initialized as an Input. Your program inside the micro is a 3-line loop that checks if the pin is "1" or not. If not goes back to the loop, if it is "1" it calls a subroutine that calls your phone. There are ready subroutines out there to call a telephone number using a computer or microprocessor system.
Cheers
You can live in your car, but you can't drive your House!