HAL for Grasshopper - How to incorporate external Inputs and Outputs?

Hi everyone,

I’m still fairly new to HAL for grasshopper so I’m having a bit of trouble figuring about how to create a setup for my ABB 140. I have the base toolpath setup and working but I need to add a feature where an attached light turns on and off based on where in the toolpath the robot currently is. Any advice or tutorials you can point me towards?

Thanks so much!