Add emulator to a builder project

I have a project created by builder (that is working!) and I would like to add a scanner emulator that will generate a ‘5’ key press every TR=1.5sec (according to the way the scanner is connected as my institute). Can I do that within the builder, or is there no choice but taking the, editing it, and leave the builder for good?

Hope it’s not too vague. I’ll happily rephrase if needed.