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Step 9 The casing (the outside)

To house the project I used some aluminum U-profiles that I have laying around from an other project. (it was approximately 45mm wide and 25mm high)

The measurements

The PCB just fits. I want two pieces of U-profile to fit over each other.
One piece must be cut the exactly the same length as it is wide. The other piece must be two times the thickness of the material shorter.
I always like to cut the material a little bit bigger than I need and then vile or sand it to the right dimensions. (this time I didn't and it shows)
The hight of the small piece is still one time the thickness of the material to high. If you put the two pieces next to each other, it is easy to draw where you must cut it. I started sanding it of, but did use the saw, when it took me to long. (and the aluminum got to hot to hold)
Now the two pieces fit into each other very nice.


Drilling the holes

To put everything together, we need to drill some holes.
The holes in the PCB dictate where the holes in the casing should come. So put the PCB in the bottom casing (the small U) and draw where the holes should come.
I'm going to put everything together with M3 bolts so I drill 3mm holes. (I always wear thick gloves when I drill small pieces like this. Sometimes the drill grabs the piece and it can hurt you badly if you don't wear gloves)
Next I put the two pieces together (upside down) and I drill the first hole all the way trough the hole I already drilled (in the bottom piece) in the top-U-piece.
Now I connect the two pieces with a M3 bolt, to make it easier to drill the other tree holes. The two pieces stay nicely together this way.
There must be one more hole in the top. This hole must be right above the light-sensor on the PCB. So put in the PCB and mark it out.
I made this hole 14 mm with special drill. It must be big enough to put the top of a finger trough it to push a button.

Comments

[tjb1]

Just an F.Y.I, you shouldn't wear gloves while operating a drill press because the glove can get caught on the drill bit and cause more harm than operating it without any form of glove on, you should clamp the pieces to the table instead of relying on your hand to grip the part.

[kenyer]

You are absolutely right. That is the right procedure. (My drill-press is nog strong enough to catch a glove tough. It will just stop. Still it is better to teach yourself to use power tools the proper way)