I did a quick experiment to find out how close the settings of the puck need to be adjusted for it to record data properly.
I started with the screw in so that the pushes could not be recorded. I recorded the start linux time and the finish linux time for each trial. During the trials, the gel sanitizer was pushed ten times with a one or two second gap between presses. After each trial, the screw was adjusted a quarter of a turn.
The first two trials showed that the puck was not activated at all. The next four showed that the puck was pretty much activated when it was pushed. (There was one dispenser press where the puck was not activated, but that could have been not pushing hard enough.) The seventh trial showed that the puck was activated by some of the presses, but it also stuck between presses. In the eighth trial, there was one activation where the gel sanitizer was sitting on the puck so that the pressure pad was always stimulated.
What I found was that the screw needs to be adjusted to within one turn to give the proper readings.
Data for each individual trial is at: http://spreadsheets.google.com/ccc?key=0Ajml4qs0jKAXdHY0aUw2TkFBNFlhOGQ4NS00bWg3NWc&hl=en