Arcade Button MIDI Controller

Step 3 Construction

Now that we have our design and the components have arrived in the mail, it's time to start cutting holes in the enclosure.

As you probably saw in the design phase, all of the dimensions for where components are to be placed are marked out. Not only does this aid the design layout, but is also useful when it comes to marking out where to cut the enclosure. I've included the schematic for my final controller design. Remember to mark out any screw holes or other mounting holes (I needed some extras for each rotary potentiometer).

Based on the schematic there are three types of holes to be made; a small 7mm hole for the rotary potentiometers, a larger 24mm hole for the arcade buttons, and a long narrow groove for the sliding potentiometers. We'll also need another small hole on the rear of the enclosure for connecting the USB cable to the Arduino board, and obviously any screw holes.

Measure and Mark Where to Cut
There are two ways to go about this step. The first is to grab a ruler and pencil and, using the schematic as a reference, mark out the center of each hole and the grooves for the sliders.

The second method (which I recently discovered on this Intructable ) is to print out a 1:1 sized copy of the schematic and stick it to the enclosure's surface. This in effect does all of the required marking and can reduce error at the same time. Given that's the case, I went with this second option.

Attached is a 1:1 schematic in pdf form, ready to print. When printing make sure it isn't being scaled before being sent off to the printer. Simply cut around the dotted rectangle so the paper will fit in the recess on the front panel, then stick it down using double sided tape. To cut the paper I'd recommend grabbing a metal ruler and a safety blade, then line up the ruler with the dotted line and run the blade down its length. This way the cuts will be nice and straight. Make sure you have something protecting your work surface underneath!

Drill the Holes
When drilling the holes it's a good idea to drill a small pilot hole first and then use the larger bits to drill the full sized holes. Start by drilling through the center of each arcade button marking on the schematic with a 2mm bit, and then do the same for the rotary potentiometer markings.

Switch over to a 7mm bit and drill through the rotary pot pilot holes to expand them. At this point I took the paper schematic off the enclosure because it was just going to get torn to shreds. Switch over to a 24mm spade bit and drill out the pilot holes for the arcade buttons. When using the spade bit remember to take it slowly to get a nice and circular hole. Make sure you have a sturdy grip or a clamp holding the enclosure lid to your work surface, else it will jump around a bit when drilling.

Getting Into the Groove
Grab a second print out of the schematic and stick it to the enclosure lid. Using a 3mm bit, drill out the screw holes for the sliding potentiometers. Now comes the tedious/fun part. To make the groove, drill a series of holes all the way down the length of the groove. The holes should be separated by no more than 1-2mm. Take your time and try to keep the holes as straight as possible.

After all of the holes have been drilled, use the countersinking bit to countersink the screw holes for the sliding potentiometers. These holes need to be countersunk otherwise the slider knob would hit the exposed screw head when it reaches the top or bottom of the groove. When drilling these I only drilled out a small amount at a time. Then I'd grab one of the countersunk screws and put it through the hole to check if the head was flush with the top of the lid. Repeat this as many times as necessary to get the nicest finish possible.

Now use the riffler files to remove the plastic between the holes which run the length of the slider groove. Also gently file the inner sides of the groove so it's as straight and as smooth as possible.