Put the freq counter back to using 5 volts and use this as an interface to the Pi:
I use that circuit to send and receive data from an Arduino to Pi, the circuits are bi-directional. Note the circuit acts as a pull up to inputs.
From reading the above, by wiring 2 buttons in series, 2 buttons have to be pressed for the safety to activate; an AND gate. Why not wire the buttons in parallel, an OR gate?
Code: Select all
switch = Button(2) ##This is the safety switch & 2 buttons in series.