Multiple holes in timer section of Best Track

Feb 21, 2013
96
0
6
12
Whats with the multiple holes in the last lane of a Best Track,
I had it punched for a Microwizard timer but there are a few holes to pick from.
I just mounted it to the largest holes and it works fine,
So what are the other holes for?
 
fff.JPG
 
To put the 1000 words that 5 Kids' pic represents, the different holes are for using different timers. I presume that Best Track drills the three sizes of holes by default.

And, not really intending to highjack this, but how are the sensors supposed to be mounted? Our timer (sorry, I cannot remember the brand off the top of my head) uses light sensors under the track picking up overhead light; when a car passes over, the signal is cut, and the time is marked from that. The bridge with the place and time display is a separate piece, connected by a cable.

Our sensors are on a green breadboard strip. I've been setting up the track and putting the sensor strip on top of a stack of cardboard to hold it against the bottom of the track. It is still very prone to being moved and the timer stops working on one or more lanes because the sensor has moved into shadow.

Another issue, at least in my mind, is that the sensors are recessed under the track by the track thickness (minus 1/4" height of the sensors).

Breadboard is similar to this (the closest pic I found online):
spacederbyfinish.jpg


Is there a way of mounting this such that it is mounted and doesn't move?

TIA,
-Eric
 
Honestly, I helped another pack who had a similar setup. We cut a piece of 1/2 plywood and glued the laser piece to it and put it under the track. That seem to keep it in place and worked just fine. We had to cut some slit to fit in the track lanes, but it was stable enough. I wish I had some pics of it to show, it would make more sense then. Something else is if the timer leans left or right use wedges to adjust on the side of track.