Step 5: Enclosure
The tin needs several sets of holes of varying diameters. I use a metal punch to mark the hole locations and brad point bits (for wood) to drill the holes. The brad point bits have a center point and two cutting edges. They won't skate and the edges cut slowly and cleanly through the metal. Brad point bits are available from Lee Valley (among other places).
Holes in the top
The three LED's, the push button switch, and the potentiometer all are attached to the top and need appropriately sized and spaced holes.
Holes in the right side
The Loc-Line arm holding the laser runs out the right side and needs a 1/2 inch hole and the USB trigger for the camera runs out the right side. It needs a 1/4 inch hole.
Even though the potentiometer allows one to change the timing interval, I found it more convenient to power the Arduino via USB from a laptop. This allowed me to upload a new timing range as I was taking pictures. This necessitated yet another 1/2 inch hole on the left side of the tin. To accommodate the USB plug I had to file it slightly wider.
Holes in the left side
Only one hole is needed in the left side. The Loc-Line arm holding the LSR runs out the left side and needs a 1/2 inch hole.