Intro: OLD SOVIET SWITCH BOX
This is a switch box I made during a renovation project of my kitchen. It was designed for looks AND function. It required a wide range of materials, tools and techniques to accomplish. I will explain each of these in this Instructable.
Step 1: The Enclosure
The box was designed to hold the switches and the gauge. The depth of the box was actually determined by the large gauge.
My first attempt at making an enclosure was rather pathetic; I cut the wood by hand using basic shop tools and glued it together. It worked, but it just wasn't good enough for me. The first version had the wiring routed through the copper pipe coming out the side. The second version had the wiring routed out of sight through the wall.
The project stayed in that half-finished state until I purchased and assembled a BlackTooth laser cutter. Now, instead of trying to cut the wood pieces by hand, I let the computer cut it for me. The panels of the second box were designed in Google Sketchup. Sketchup is great for 3D object design, but 2D images can be created in it too. All the pieces were cut in 15 minutes with the laser cutter from a single piece of 1/8" Baltic Birch plywood. The interlocking edges made glueing the pieces together a piece of cake.
Step 2: Weathering and Rust
The insignia, lettering, and weathered finish were added to make it look as decrepit as possible. I really wanted it to look grungy, crusty and exotic. I eventually stumbled on this YouTube video which showed a simple technique to create an aged-metal finish.
The edges of the box were filled in to hide the joints. the whole box was then given a couple coats of primer. I did not have any textured spray paint but I came up with something just as good: while the primer was still wet, I sprinkled sand onto the paint! After a couple splotchy coats of silver metal spray paint, it's ready for rust! The video suggested using red paint and oatmeal for the "flaky rust" parts. I added one other ingredient to that mixture: white glue. As mentioned in the video, paint and oatmeal can be rather delicate after it dries, but by adding some simple white glue to the mix it became a much more solid "sculpture" when it dries. After several strategic application of brown, red, and black wash, I had an authentic look!
Step 3: Labels and Insignia
To make the labels and insignia, I used my trusty Printrbot 3D printer to print files created in Sketchup. The foreign text was created using the simple technique outlined in this video. I didn't care what the words actually meant, what I wanted were words with lots of those strange Cyrillic characters in them. I simply entered random words in Google Translate until I found ones that looked "right."
The labels and insignia were painted with craft paint and weathered in much the same way as the box enclosure. The base was given a black layer, and the raised areas were painted red. I added a couple layers of Modge Podge* to the labels to help the paint stick to the raw PLA plastic and seal the paint afterwards.
* Modge Podge is really not much more than white glue.
Step 4: Front Switches
I wanted the controls on this thing to actually work! On the front is a 4-position rotary switch with indicator lights that turn on when the switch is at that position. The rotary switch controls some light clusters in the kitchen. I could have routed power to the lights directly through the switch, but a more flexible option was to use an Arduino and control the lights indirectly. The rotary switch therefore only has 5V current connected to it, which serves as signaling input to the Arduino. Each switch position routes the incoming 5V to a different input pin on the Arduino. The programming of the Arduino determines what it does in response. The Arduino has two Powerswitch Tail relays connected to output pins. The relays switch on 120V household current for the corresponding lights. (One of the lights is a Lava Lamp)
The picture shows the wiring diagram with the rotary switch in the lower left. The relays are in the upper right corner. The diagram was drawn with Fritzing, a VERY useful program itself. The diagram shows how 5V comes into the rotary switch and is sent to one of 3 input pins on the Arduino. In response to the position of the switch, the Arduino will also activate the corresponding indicator light. The indicator LEDs are connected directly to an output pin of the Arduino.
The position chart shows which lights are on or off depending on the rotary switch position.
The other single switch on the front is a plain 120V single-pole switch that will eventually control another light. it is not yet connected to anything, but it is there, waiting...
Step 5: Knife Switch
The oversized knife switch actually does control current, but it is only 5v, and switches an LED array. I added exposed wiring to make it look...dangerous....
Step 6: The Gauge
The gauge was acquired before the box was built; the enclosure was actually designed around the gauge.
The gauge was purchased through ebay, shipped from a former Soviet republic (I forgot which one). I bought it cheap, not knowing what operated it, purely because it looked fancy and mysterious, with strange lettering on it. When I finally got it I realized that it was some sort of pressure gauge; the back of it had two ports that were actually labeled with a "+" and a "-", and I could make the needle fully deflect by literally blowing into the "+" port! I came to the conclusion that it measured air pressure variations of a relatively minor degree. The dial also glowed in the dark, another bonus. I really wanted it to be functional to the point where it would move in response to the state of the switches on the front. I first tried to connect the "+" port to a simple turkey baster squeeze bulb with a rubber hose, and while it actually worked to activate the needle(!), it was not a good enough arrangement for a permanent solution. I reluctantly and carefully took the gauge apart, and as I suspected, the heart of the gauge was an aneroid, a flexible metal bellows, which literally expanded or shrank in response to changes in air pressure. I ultimately ended up removing the aneroid and in its place I attached a hobby servo. The original mechanical linkages connected to the bellcrank of the servo quite well, all I had to really do was make a short connector out of spring wire.
The servo wires ran out of the back of the gauge housing, through a hole originally intended for an air line. By hooking the servo to the Arduino and including the standard servo library in the program, I could control the position of the needle directly. The needle now moves in response to the position of the rotary switch.
Step 7: The Arduino Brain
The Arduino is what makes the whole thing work. Although there was technically enough room inside the box to hold the Arduino, experience had taught me not to try to cram things into such a small space unless absolutely necessary. I eventually mounted the Arduino behind a nearby bench seat and strung all the necessary wires behind the wall. In the photo the Arduino is in a electrical work box with a breadboard below it. The Arduino runs off the sketch available here. As mentioned in the "switches" step, using the Arduino as the central brain allows for maximum flexibility. The indicator lights, relays and gauge are all controlled by the microcontroller.
IF YOU WANT A FULL COPY OF THE ARDUINO SKETCH, IT IS AVAILABLE HERE
Step 8: Mounting on Wall
I routed all the wiring through the wall and to the nearby Arduino unit (also out of sight). The LEDs for the front indicator lights were hot-glued into holes in a piece of wood which was attached to the inside of the case such that the lights were directly inside of the holes for the colored glass covers. The picture also shows the rotary switch and single switch. The switches will be attached to the case through the back. The box is secured to the wall after all the LEDs and switches have been attached to the inside of the case. Then the gauge is connected to its control wiring and the gauge is secured in its hole.