Idk if that is possible at all. I saw posted requests about detection of units even if they did not move.
In case MotionScanner is a derivative from Mind Probe it will detect all units in the zone no matter if they moved or not hence it will be a "Scanner".
Please note that this device is called a
Motion Scanner. If X-Com developers wanted a scanner to detect any unit, moving or not, they would have done so... While not a coder, I am fairly certain that it would be easier to program without the additional movement check. But evidently that's not what they intended, so they went the extra mile and added this requirement. As for why, we can only theorize, but it was probably influenced by
Alien and other titles which had explicit movement scanners.
On second thought, perhaps humanity developed Motion Scanner based on sonars / microphones to be able to detect movements behind the walls and pinpoint locations. That correctly makes Motion Scanner a tech available from the start. Oops.
It's a gizmo that goes blip, there is no solid explanation how it works and none is needed. If you want, you can explain it like this.
Having said that, a separate psi scanner would be an interesting idea, as long as the engine allowed making robotic units and such undetectable to psi. (Robots aren't psionic, right?
)