Several people asked about the control panels we had on our demos at the St. Louis RPM meet. They are easy to make, so I figured I’d share the process.
I first read about the process used to make the control panels 20 or so years ago in the Model Railroader series published in book form as “Building the Burlington Northern RR in N Scale”. The materials and software were different, but the basic idea is still the same. Print off the panel artwork, sandwich between some clear plastic, drill, install. After having made a few of these over the years, there are some tips to offer that can make the process go more smoothly.
Step 1: Artwork
The most critical part is creating the artwork. Any drawing program can be used. Personally, I’ve been using the free Inkscape vector drawing package. When creating the artwork, be sure to include proper clearance around LEDs and switches to accommodate the mounting hardware you plan to use. Also, be sure to include mounting holes in the corners.
After creating the artwork, print it out using a color printer on high-quality paper. You will obviously need one for the actual panel, but print a couple extras to use as templates and in case the first one gets damaged.
Step 2: Plastic
The next step is to create the plastic sandwich in preparation for cutting and drilling. I use Lexan as it is less prone to chipping and cracking and can easily be cut to size on a table saw. Align two pieces and tape the corners with electrical tape to hold them in alignment.
Next, attach the template drawing to the top. I cut triangles in the corners to help align the drawing with the plastic underneath.
Step 3: Drilling
Once the template is aligned, use a sharp object (an X-acto knife in this case) to mark the centers of each hole to be drilled. Poke the center, then twist a little to make a small dimple in the surface of the plastic.
Drilling is accomplished with a drill press and bits sized for the particular hardware being used. I used brad-point bits to make aligning the bit with the marked hole center a lot easier.
Note: In the photo below I show the artwork sandwiched between the two pieces of Lexan. In the past, I’ve tried this with poor results. This time, I decided to try it again, but first attach the paper to the back piece using spray adhesive. Didn’t work. The paper still caught on the bit, ripped, and twisted all around the hole. I had to replace the artwork in the end. You’re better off just drilling the plastic without the artwork in place. The holes are already marked, so there is really no need to have the artwork there during this step.
After drilling all the holes, align the actual artwork between the plastic pieces. Be sure to first remove the inner protective films on the Lexan. Once aligned and re-taped, cut out the holes. Start by piercing the paper near the edge and then slide the knife around the hole. Make sure to use a new (or very sharp) blade.
Step 4: Hardware
After cutting all the holes, it is now time to install the hardware. First remove the protective film on all sides of the plastic. Switches and other threaded hardware can be mounted first. This helps hold the plastic sandwich together.
The LEDs are mounted using LED holders. I like the ones from SparkFun. First, insert the LED into the holder, then press the combination through the plastic.
The only thing left to do now is to wire the panel and then mount it using the corner screw holes. Wiring can be accomplished with point-to-point soldering (i.e. “structural solder”) on the back side. Use the component leads as interconnect wherever possible, and don’t forget to include current limiting resistors on any LEDs. Checking polarity often is also wise, as it is a lot easier to correct a mistake before applying the solder…