This is great but why cannot you do it? I think it is cheaper, no mechanics (that can fail), easier to build and only you have to disable it by software. Even if user pushes the button, nothing will...
Yes, that explains everything. Unfortunately, I can't use the HSERIN/HSEROUT ports available in the 18F4550 because they are already taken doing the hardware communication. Increasing the baud rate...
Re: CircuitLab simulation
Have you tried LTspice? It is totally free and great support either on YouTube or from forums around.
Ioannis Today, 18:24I admit, it is a bit strange if the component is not in the lib and you have somehow to add...