Hi So i have made the circuits and they seam to work as expected (i did not do the sensor as it is no longer needed)
however
i removed R2 from the output stage as it seams to not be needed, I also had to add a pull down (10R) onto the gate of the fets as some of them would not turn off.
I put a LED in series with the Optos on the input stage for visual feedback
I lowered the voltage of the circuit to 12v so that i could use the raw input into the arduino for its power supply.
the one part i am still not sure on is R2 on the input stage
i have yet to install this as i can not decide if it is needed,
the circuit is working and it takes 3.3V before the opto begins to conduct current,
however i am wondering if i should install this pull down resistor to stop the input pin from floating or not, my main concern is external interference causing the opto to light and trigger the input.
the circuit is working atm however once the project is complete it will be moved out of the workshop and installed onsite so i need to be sure the conditions on site are not going to cause false triggers.
can anyone advise me on this?