/diy/ - Do It Yourself

>>2391140
>>2391173
You can have the optocouplers either common-emitter or common-collector, doesn't matter since the phototransistors have a floating base. But whichever way you go, you'll need pull-up/pull-down resistors respectively. Circuit A would work with pull-down resistors.

Also the arduino may have a register you can set to invert input logic levels. I know my MCU has one to invert output logic levels, not sure if it works on inputs too. Either way I bet some demorgan's laws could help you clean up the logic. Not like you'll be pressed for processor time.

Additionally, it's an option to flip the opto LED circuit so they're turned off only when the button is pressed. Though I'd definitely go common-collector before resorting to that.

t. starting another unskilled retail job tomorrow