Basically what I am trying to do is measure the deflection of a plastic ceiling panel when it is backloaded(weight placed ontop from behind the panel). Need to be able to measure with a resolution better than atleast 3mm. Multiple different areas on the panel would be measured. I was looking at time of flight sensors (ultrasonic and laser) but couldnt find anything with good enough resolution + accuracy and i'm not even sure if they are suitable for this application. Also tried exploring alternate methods with an accelerometer and similar but does not seem plausible.