Has anyone faced a Daubert/Robinson challenge on the PBT. If so, how did you handle it? Did you treat it as a non-scientific device or did it require you to have expert testimony to determine its reliability?

Never been down that road because it's my understanding that the actual results are unreliable and thus inadmissible. All we do is let the jury infer from the taking of the test and the Def's later refusal to take a breathalizer(SP?) is because the Defendant knew he would flunk it again.

My understanding is the actual results from the PBT are not admissible, but I have used it to ask my officers if they determined (by using the PBT) if there was a presence of alcohol.

I assume your question deals with a challenge even to the fact that the PBT result was "positive". Not all courts even agree on this, but I think you could cite Iron Cloud, 171 F.3d at 591 fn. 5 for the idea that without any proof as to reliability or scientific basis it is admissible as a "screening test" useful to determine probable cause (or bolster the officer's opinion as to loss of use). This particular issue was not raised in Fernandez, 915 S.W.2d at 576, but it should help as well.