Creating 3D models of switches, knobs, dials, meters, and panels is not as easy as it looks.
I really wish I were an expert with a 3D mechanical CAD package. A few months ago, I was all gung-ho about learning DesignSpark Mechanical. I downloaded the free software to my computer, but I never seem to find the time to learn how to use it.
Fortunately for me, I have a friend, Eugene (Willie) Richards, who sits in the next bay to my office. He is an absolute diva with regards to all things mechanical, including running mechanical CAD packages. He's also a black belt when it comes to fabrication using sheet metal. That's why he's helping me design and build my robot chassis.
More recently, Willie has been helping me with my Pedagogical and Phantasmagorical Inamorata Prognostication Engine project. As you may recall, this involves a bunch of antique knobs, switches, analog meters, and suchlike, all of which will be mounted on a brass control panel that will be presented in a beautiful wooden radio cabinet from 1929.
Of course, when you are designing something like this, you can't leave anything to chance. I didn't have a clue as to the thickness of the brass sheet I required, where to get it, or anything like that. Fortunately, Willie told me what to get and where it could be obtained. Meanwhile, he whipped out his micrometer and measured all my antique switches, potentiometers, knobs, and analog meters. He created 3D models of the little rascals, followed by models of entire panels. A 3D realization is shown below.
Observe the raised brass bezels around the switches and knobs. Also observe the little white circles mounted in these bezels. The little white dots are faux mother-of-pearl, behind which I will mount tri-colored NeoPixels from Adafruit. I'm using the NeoPixel Rings around the potentiometers and the individual Flora NeoPixels for the switches.
One thing I have to say about Willie is that he's a perfectionist. Whenever I asked him to print me a quick drawing of a part for me to peruse and ponder, he wouldn't do anything by half-measures, even though I wasn't using the drawing for manufacturing. He insisted on generating both 2D and 3D views and fully dimensioning everything, just in case.
All the brass pieces have now been cut out using a mega-cool water-jet thingy. I just got the main panels back from manufacturing. (The bezels are still having their chamfers added and being polished.) The photo below shows the upper panel with a meter I popped in just to see what it looked like.
I've also got a bunch of small (2" x 4") rectangular brass offcuts that I will use to experiment with different aging techniques. I don't want my panels to look shiny and new; I want them to have a patina and look as though they originated in Victorian times. That's what I'll be playing with as soon as I return from the EE Live! 2014 Conference and Exhibition. And, of course, I will talk about all this in my Bacon, Beerfest & Prognostication Engines presentation at EE Live!
But we digress. I ran into one slight problem. I realized that I lacked the nuts and bolts to hold the various meters to the front panels. Obviously, I don't want to use anything like a steel bolt with a Philips head. I'm looking for something made out of brass with a slotted head. Also, I was missing some very unusual nuts for the antique switches.
I bounced over to Willie's office with my meters and switches in hand, and I explained the problem. Out came his micrometer again, accompanied by mutterings about diameters, threads per inch, and this and that. Before I knew it, I was armed with a list of part numbers to order from a company called McMaster-Carr.
Now, I have to give a shout out to the folks at McMaster-Carr. As soon as I returned to my office, I placed my order online. A couple of minutes later, I received a phone call from McMaster-Carr checking me out, because it had a different company registered to the address I'd given. I have my office in the building of an engineering company called MaxVision (no relation). It didn't take long to sort everything out. The amazing thing was that this all took place on Wednesday afternoon and, even though McMaster-Carr is in a different state, my package of nuts, bolts, washers, and stuff arrived the very next morning by regular post. This means the packing and shipping department must really be on the ball. Color me impressed.
So there we are. I'm a very happy camper. As soon as I've aged my front panels, I'll mount all the switches, meters, and stuff. Then I'll connect everything up to my Arduino Mega via my Universal Screw-Block Proto-Shield. Of course, I will keep you informed on progress in future columns.
As a final note, you may be interested to hear that Willie (with his manager's permission) is available to perform freelance mechanical design work, including creating 2D and 3D mechanical CAD drawings and generating appropriate formats for controlling fabrication machines. Feel free to email him at firstname.lastname@example.org. In the meantime, what do you think about the progress of my Inamorata Prognostication Engine?
— Max Maxfield, Editor of All Things Fun & Interesting