a microcontroller and the car Brake pedal

plz help i need a sensor or a circuit to detect
the state of the Brake pedal position
of the car is it on /off
can i use a push button to perform that task
(push button connected to the Brake pedal of the car
when the driver presses the Brake pedal he also
pushes the push button and sends an
interrupt to a micro controller )
plz help?

There is already a pressure-sensitive switch connected to the break pedal and you can tap off this.
It's the brake-lights switch.