Quote Originally Posted by Ioannis View Post
...When the switch is at ground, the HC14 sees the voltage divider of two 10K resistors, so the voltage is at 2.5Volts.
...
I would strongly recommend to increase the 10K pull up to 100K.

Ioannis

I'm going to test this using 10K pull-up and a 1K res and see what that turns out (I'd like to do the math, but my hair hurts ).