Force to trigger function.

[DRedshot]

You place two areas a certain distance from one another.
Place the first area a few inches away from the wall, and put the second on the wall.

Measure the distance between these areas, and declare it in your script as a constant, ie:
float Distance = 0.25f;

Now when the hammer passes through the first area, start a timer, and when it passes through the second timer, call "GetTimerTimeLeft" and use this value to work out the time taken for the collision.

Now divide the Distance by this number to calculate the speed, and have an if statement to check if the speed is larger than a certain value!


Edit: already answered