It picks up readings (6)
I believe the answer is:
sensor
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">it picks up readings</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for sensor that I've seen before include "Detector" , "Detection device" , "A furtive look" , "that could provide a smokescreen" , "Detecting device" .)