With several boards done or in process it is time to work on moving parts.
In general translating the 10x motion to 1x seems like a pointless endeavour. Rotary motion translates easily but up and down left and right not so much. There should also be a level of robustness that is not as necessary for static parts.
So I'll just build working switches instead of embedding any components.
Starting with a dip I decided to try some vacuum forming, mostly because I've never tried it before. I had lots of milk jugs laying around for another project (my semi-submergible cow-headed sea-monster milk carton boat).
Probably the most tedious and mundane task in the entire project is the construction of the solder-less breadboard itself. This is only important in that it will be the job most likely to devolve to the instructor. You can get enthusiastic help constructing the 10x components. But that enthusiasm wanes quickly when talking about hundreds of tie points. So when constructing the board I am trying to keep in mind not only the wide availability of materials, but also the ease of construction.
There is no single right way to build the board. What I am going to do is give a series of indicators and things I've tried that work.
The following will assume we are scaling up from 1/10 inch to 1 inch.
Lets break the board down into the face, the connective rails and the separators.
Looking at a board the key features are apparent. Holes. Lots of Holes. But the holes tend to be in groups of five. The other common distinguishing feature is the trough or troughs. Depending on the board the other areas lacking holes, call them the borders also show up.
The obvious first choice of material for the face is 1 inch pegboard. Filling in unneeded holes is a lot less work then drilling the needed ones. But if you choose to use another material the very first thing you should do is make a drilling jig.
The Idea here is to get a good solid grid before you start drilling. I started with some graph paper and got a solid 1 inch square by driving an 8d nail through the 4 corners. This gave me a good start on maintaining parallel. Using the nail marks as if a center punched I then drilled them out. Using this small jig I then built a 5 x 5 jig. From there maintain parallel and spacing is simply a matter of remembering where you are. Of course in the next iteration of the jig I just ran it on the CNC.
If you are going to construct the face out of poster-board or other cardboard like material you could just drive the nails through and skip drilling altogether. As we are incorporating one version of the board as a section of white board I felt it important to show a way to get the correct spacings.
The trough is important but only in that it is a handy indication. The board does not actually need a physical indentation. For most field construction I expect that no indentation will actually be made and the trough will simply be a blank (hole-less) area.
The borders are also simply aesthetic.
The rails that provide the connectivity are the true heart of the board.
Looking at the guts of a breadboard you will see that it uses a simple bent metal spring. The bends clamp down on the wire and provide the connectivity and the support. Normally the rail is bent into a flat bottom U shape with addition V shaped bends near the top to clamp onto the wire. A notch is cut between every inch so one wire doesn't effect the wire in to hole next to it for the spring action.
Many different materials can and probably will be used to construct the Rails. The spring action can be accomplished with the material use to electrically separate the rails.
During the setup for our Maker Faire the box of my premade rails got misplaced. I had a bunch of cut foam ready for rail construction. What I didn't have was time to bend the rails. Solution, stuff the foam with steel wool. While anyone who camps a lot would never recommend that for a long term solution (steel wool and a battery makes a pretty good fire starter), it did the job quite well.
I've used Roof flashing, partially untwisted wire rope, steel pallet strapping, crumpled aluminum foil and soda cans so far.
Soda cans work really well. You first have to lightly sand the coating off and then what I do is roll it around a thick pencil pinch flattening it as I slid the roll off. Pinching lets it hold its shape. Because the material is so thin and flexible there really is no reason to notch it. Oxidation may become an issue but so far it hasn't and since aluminum oxidizes so quickly I doubt it will. The ubiquitousness of material far outweighs any downside.
There is no reason that I can see that the rails need to be connected side to side. My normal configuration right now is two rolled and pinched soda can rails side by side. This allows for some slop in the construction.
What material you use for the rails may determine what material you choose to electrically separate the rails. Foam insulation works well for most, but harder materials tend to chew it up. Foam has the advantage of allowing the wire to be embedded in it making vertical displays more practical. Wood works for non-loose packed materials. With loose packed material it doesn't provide the spring that foam does. But it works well with pallet strapping tape.
There are a tremendous variety of materials that can be used to construct the board. The limitations are simply time and tenacity.
I do however highly recommend that you build the Rail and Separator combination in Five hole groups. Trying to router out the underside of the board and then insert the rails. There really is a reason that house builders work with 1/16th of play. The amount of wasted material you generate is not worth the effort.
We had our Maker Faire over the weekend. We thought it a good time to present the project to a wider audience. A photo resister, a phone handset speaker some caps ,a 555 and we had a simple circuit to demos. It had to be simple because getting ready for the event cut into any time we had to work on the project.
I'm psyched and pumped.
We had the circuit setup on the board with a couple of real size boards and components next to it. The idea being we could get people to copy the 10x in real scale. So I'm sitting at the table and a boy and his mom walk by. Mom is interested in the next table and the kid not so much. He walks up and looks at the 10x, then looks at the smaller ones, looks at the 10x, looks at the smaller ones and looks at me. Not saying a word I give him the OK if you want to shrug. He picks up the 555 glancing at me, I nod, he looks at the 10x board and puts the 555 on the real scale board. I'm floored, the concept works as he builds the circuit I want to jump and shout.
A small incident but it says it all.
As the day rolled on I came to see that it will also work the other way. Smaller kids also want to make it blink and beep. Kids capable of understanding but just not quite in control of their body enough to put the puzzle together without getting frustrated. Now they can have a pathway. I had always thought of going from big to small, ow I realize that small to big is equally valid. Watching Mike explain to a child how changing this would change that I deeply regret that I didn't have more 10x components ready so they could get their hands on it. I also wish I had enough rime to assemble the materials for construction. But all in all a good day.
Yesterday was set up as a build day. A chance to get members outside of the core team a chance to participate and get their feedback.
I decided to work on an eight switch Dip.
Translating motion from inch to a tenth of an inch for switches seems a bit pointless so no part embedding will be done. I'm just going to build a switch.
The lashed up rig worked well enough and did the job. But I've decided to abandon that and just mold them from polymer clay or some other material.
It also became clear that our open builds for the public will have to have a bit more structure then I thought. While I always anticipated using these build as an opportunity to teach electronic components and soldiering, the need to teach about fabrication became clear.