Absolutely. You basically need to find the "unlock" wire in your car and wire into that. Depending on the power supply or the setup it will differ for you though. If you have a laptop, its a matter of running power to it, and then pushing the button in some way. This is how mine was supposed to work. You also have to keep in mind to disable this feature if the computer is on though. So that you don't trigger it again accidentally.
I don't have an OPUS, so I have no idea on how they are triggered. I think it is all triggered off of the accessory voltages though. If the power supply gets power to the trigger wire, it turns on. If that same voltage goes away, the computer gets shut down. Other than that I have no idea.
I tried to build something myself, but the weather got too bad to spend any time out there to actually install it.