Thursday, July 19, 2012

Apollo 13: Faceplate Design and Acquiring Parts

Apollo 13, attempting to be cool and not succeeding at it picture.

With the two big questions out of the way, the next most popular one is "If you had to pick one part of the project, which one was the hardest?" My answer thus far hasn't changed, "As a guy who has never done something like this? All of it."

The parts list, like many parts of this project was crucial in helping recreate the experience and look of the fabled controller in question. The problem is they were based on the unknown dimensions of a oddly shaped box. But the following picture changed all of that for me.



In the above picture, we see the Maven pictured between an Apple laptop and Pioneer DJM800 mixer. What's more, a front facing pic helped reveal an onboard analog sound output, there are headphones plugged into this thing! More importantly, the jack is tilted downwards. All in all this was great, because I knew a quick google search would yield http://www.pioneerelectronics.com/PUSA/DJ/Mixers/DJM-800 and the exact WxDxH dimensions of 12.6 x 15.0 x 4.3 - perfect. I now have a relative size to begin basing this off of, judging by the first photo it was clear the device was larger, and accounting for the tilt I estimated the faceplate of the Maven to be 13.1 x 17 inches (width x height). But let's be honest, not everything is perfect the first time around...


So in the week I gave myself to learn AutoCad with my 30 day trial, I managed to produce 3 different versions within 4 days. The very first drawing is the furthest one on the right (hence the v1.0 mark beneath it). You can see that i originally drew a very wide looking mixer and approximate sizes of all the various functions on it. Version 2 i got a bit better with my measurements, and realized i could tighten things up significantly. Additionally there is a significant design change that occured, between version 1 and 2 you'll notice the majority of the potionmeters (knobs) shift their positioning so the pins beneath the board are facing different directions. This was done to avoid any wires bumping into the side of the eventual box, other inputs, and make wiring slightly easier. But I could probably could go tighter, version 3 introduces even more accurate measurements on my behalf and a more compressed design. But you know what helps? Calipers.


Which i have no problem admitting, didn't know what they were until this project. For those equally unaware, its just a measuring instrument that lets you make very insanely fine measurements - perfect for taking the width of a knob, button, or length of a fader.


Version 4 introduced two things - layering and Mitch. Mitch for all intents and purposes helped me refine version 3 into version 4. He showed me layering and the importance of it. Now I am personally a huge Photoshop person, so the value of layering instantly clicked with me, more than anything I just didn't know how to do it in AutoCad. But that was solved relatively fast with him. For the sake of explaining the color coding, all RED lines represent what you see on the faceplate, the holes, the slits, etc. The BLUE lines represent the actual size of the object resting behind the board. The YELLOW lines are merely notation for the sake of alignment and seeing individual channels clearly AND also show a relative size of the knob/fader. This is the first version where I realized these dimensions of 13.1 x 17 were going to be the final dimensions I was going with. This version was cut on 1/8" plastic, the following are ALL the pictures of that process.










Hurray!!! It exists! Kind of! But i felt a minor success none the less. However the second I started mounting parts I realized one thing (go look at version 4 cad again)....go ahead I'll wait.

Doo da dooo....

Find it? Well if you didn't thats ok, the 8 knobs and 8 buttons featured along the right side of the mixer had the knobs oriented in such a way that the pins for them were pointing towards the box edge. I knew this was a wiring issue not worth going through. Version 5 (The Final Design) was created, and last minute changes were made.

This is the final faceplate. Holes for mounting, and turned the knobs to face away from the edges.


If you notice anything about this design and the final product I have is that I left ample space for text. I haven't given up yet! Also some of you may notice a tiny red notch on all the knobs, that's the place for what's known as the "key" of a knob. If you scroll down and look at the photo of the knob, you'll see a very tiny peice of metal jutting up from the side of the knob. Apart from screwing the washer/nut to attach these knobs to the board, the key ensures the knob doesn't turn in place.

Some of you may also be wondering (as did I when this started) - how the hell do I drill holes for the faders? How do you make that measurement - calipers! You can measure the distance! Or you could look up the physical parts schematic sheets as they offer the measurements for you, but I found more satisfaction in doing this myself.

Now I didn't return to make the final cut for another month, I just need to order some kind of metal and I still hadn't decided on it at that point in time. I figured I'll worry about it later, I was more concerned with the the next challege - acquiring parts and wiring it all together.

The Parts List
Now some of you maybe asking "You designed the faceplate without parts?" No the parts were done in tandem with the above steps (it was a really rough week learning CAD and speccing out parts!) as I kept looking for parts I kept refining the design. So I had the relative dimensions based of off another mixer in that above photo. The question was how could I determine the relative size of the inputs on the board? Fortunately I discovered this photo.


This was the photo that sealed the deal. Seeing Sasha's arm positioned next to the device said a LOT about the size of the mixer, it's components, and it clearly showed off the extreme tilt of this box! Sure his arm is bent at the elbow, but that was easy to accommodate for. Which helped me arrive at the following...

Large Fadershttp://www.digikey.com/product-detail/en/PS100-2B1AR10K/987-1407-ND/2620676?cur=USD (i wanted linear, but i could only get them in logarithmic). These are mounted directly to the faceplate.

Short Fadershttp://www.allelectronics.com/make-a-store/item/SPA-20K/20K-OHM-SLIDE-POTENTIOMETER/1.html (these are mounted to perf board from Radio Shack, I didn't use copper perf board. Just the simple stuff.)



Knobs - These can be found anywhere, it is a 10kOhm Linear potentiometer. It also goes by b10k. Common short hand for "linear" is a preceding B before the resistance value. If you see A it implies the fader is "logarithmic" - I suggest ebay. They are uber cheap. Outside of the resistance value, the two dimensions below help contribute the a very minimal fader. (these are mounted directly to the faceplate)


For anyone who doesn't know what it means to have a linear or logarithmic fader - let me save you the technical verbiage, research, and some time. 
If you have a linear fader, you have a 1 to 1 mapping. If the physical fader is positioned in the middle, you will see it positioned in the middle in software. In fact wherever you see the physical fader lies you will see it identically placed in software. 

If you have a logarithmic fader, you don't have a 1 to 1 mapping. You have an implicit curve hard defined within the fader. Better yet, let's imagine it as a crossfader with two hard defined curves. Bottom to middle is a very wide/long/open curve - it takes a huge push to get even a little volume. But the middle to top? A very sharp/fast curve. The tiniest push is a huge shift in the volume.

I somehow had some no name faders laying around (after 2 months of research I discovered there were knockoff Alps faders and thus aren't manufactured anywhere), and just so happened to find faders that were the exact specification of those. Why was this important? I forgot to tell you, I designed the CAD file around those original no name faders! Faders I thought I could purchase again! I was wrong. Talk about 4 days of hell racing to find a fader with nearly identical dimensions. Ugh, never again. BUT! The large faders I found were the ones that are listed above. The Apollo 13 features 7 logarithmic channel faders (channels 1-6, plus master volume) and 2 linear faders (master BPM and the crossfader). Doing this you can quickly slap a fader to kill volume to a channel, and you don't have to do it all the way down. Just hit about the middle and it'll be dead. But the master BPM and crossfaders absolutely had to have a linear fader. Just a bit of a personal preference.


Sweet! But, wait...the buttons. The Buttons! THE FREAKING BUTTONS THAT LIGHT UP! TELL ME ABOUT THOSE!
I spent an absolute stupid amount of time trying to find the identical buttons used in the Maven. My only conclusion is they are custom made, because I can't find this kind of design anywhere...


This is one of the most close up shots I've ever found of the device, and it really highlights the size and design of those LED push buttons. That and the font that was custom designed, which you'll notice I recreated...


I digress.

The buttons! Ok, so after a lot of searching. A lot of phone calls. Hundreds of quotes. Using a bunch of musical gear and contacting major manufactures of dj equipment, I purchased these...

The LP15R1 by E-Switch

These little beauties are FAN.FREAKING.TASTIC. They are insanely bright and the best part? Come in all the colors you need to build a Maven. Green. Red. Blue.

LP15R1WHTGRN-N
LP15R1WHTRED-N
LP15R1WHTBLU-N

Now I made the purchase from Newark/Element14, however I absolutely must emphasize these things vary wildly in price and I completely lucked out of purchasing them when they were selling these things for $2.66 a piece. The price has changed since then and I advise everyone to absolutely search the hell out of these things before buying. But they snap into perf board ever so nicely with those 4 gold...fangs? I'm going to call them that. Fangs. There I said it. Fangs.


I had to build 6 of these little boards (obviously) as these are all the green buttons that represent the clips that will be launched in the 6x6 matrix. Emphasis on matrix. These are wired in matrix. But i'll get to that in later posts.

I'm sighing all over again just looking at this photo.

So there you have it everyone, those four parts make up this entire board. This entire MIDI Board. They are either mounted directly to the faceplate or perfboard that then mounts to the faceplate via Nylon Standoffs. If you are wondering what the white pegs jutting out from the perf board are called, they are nylon standoffs that...well do just that, help something stand off from the surface. Here's a link! http://www.sparkfun.com/products/10462. I used 3/4" nylon stand offs in this project for all perf mounted inputs. Which to summarize, all perf board requiring standoffs were any LED Pushbutton or any short fader used.


Alright so maybe it's five parts because of the standoffs.
Wait, six I forgot about the perf board.

Until next time!
This wraps the first of many more posts to come outlining the design, my thought process, and all things Apollo 13 so you can build your very own. I encourage comments, questions, emails, skype phone calls, you name it - i want to make this fun and easy for everyone. I also hope these posts are living up to what the people who are following this project expect these posts to be.

I think I'm going to shoot for Tuesdays and Thursdays 7-8pm central time to post new articles. I'll try to step it up if i can, but I'm confident I can at least keep that promise of twice a week. More importantly this post introduces another thing people are itching for - downloads. So, let the downloads begin.



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5 comments:

Baidawi Ishere said...

Sometimes I abhor the internet. Sometimes I love it. At the moment, this post definitely inspires the latter.

WillDaTrill said...

This is just awesome... I wish I had access to these equipment. I have so much things to make... Great Job!!!

Gary Melancon said...

You need to put up a paypal tip jar. I'm certain that the fine folks reading this would donate a couple bucks for your kindness in sharing all this.

Dennis eCue said...

Seriously awesome article, I know nothing about electricity or hardware design at all, and a quick skim through your step-by-step, I'm confident that with the right tools and supplies, even I could do this. GREAT JOB!

Brandon Hudson said...

I like your style of writing. You break it down nicely. Very informative post. Keep up the good work.

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