Hi,
This can be done in several ways. The easy part is sensing the hit, but differentiating eg. a rim shot from a regular beat and whiskers vs. drum sticks may be a bit more work.
Sensors for the impact can be; Piezo disks, ferrite core coils, several types of microphones (but they will be sensitive to other sound as well), a magnet and pickup coil (or linear Hall element) and so on.
Coils will not sense other sound, but may be prone to picking up magnetically induced noise, piezo might sense other sound, depending on how it's done, but is not sensitive to magnetic fields.
Several parameters must be judged against each other, as well as your ability to mount the sensor, which will differ depending on choice of sensor.
So, what kind of precision is needed?
And what output do you need?