The Name is Type… Prototype
Before any serious construction on the board can begin, the basic premise of lighting a translucent rectangle of plastic with an LED needs to be vetted. So, it was time to go to the workshop and figure out how to best cut tiny pieces of plastic and assemble them into a workable shape. After a few false starts with the table saw and miter saw, I figured out a few approaches that seemed reasonably safe, and which did not involve flinging plastic cuttings across the garage at high velocity.
Once I had some pieces of approximately the right size prepared, I assembled a prototype test box using that most familiar of all quality construction tools, Scotch tape. (Did you know Scotch tape was named based on an ethnic slur, saying that someone’s boss was being cheap? Go look it up somewhere.) Hey, it did the job. Hooked up an RGB LED, wired some reasonable colors using different resistors, put the box over it, and… oh dear. Even using a diffused LED lens, it’s still very obvious that there are three separate color elements under the plastic, and the top of it is lit very differently than the bottom. Well, this won’t do at all.
After some research, it seems that the best solution to this is to mount the LED to the side of the box, rather than the bottom, then coat the inside of the box with a white material to reflect the light, giving it a much larger space in which to mix. So, after a visit to the trusty drill press and application of some very expensive typing paper with more Scotch tape, my side fire test was ready. This time, I had much more pleasing results, with reasonable color mixing and no particular hot spots. I still needed to keep the LED from being too close to the top of the box, or it would give a hot spot, though, so I can’t make the board as completely thin and streamlined as I had perhaps hoped. This is still well within the realm of reason, though.
Next step is to actually light the prototype box using an LED powered by the LED driver chip. Until that test is performed, I can’t be sure that a single LED will be sufficient to light the whole space. If I need to light two per space, things may get complicated, so let’s hope that’s not a problem.
The Gathering (of Materials)
This will be an ongoing process, acquiring all the stuff needed to make this project a reality. I’m actually back-dating a few of these posts as I’m starting the documentation process, so I may have skipped a few steps here and there. Anyway, here’s some of the stuff that’s already come together to start making this happen.
- Acrylic, and lots of it! Turns out a local plastics supplier, Regal Plastics, has a scrap pile. You can go rummage around and get their leftovers for cheap. I picked up a variety of different plastics including opaque black, translucent white, and transparent clear for about $8.00. Hopefully I have enough for what I need to do, but even if not, it gives me lots of material to test with and decide what will work best.
- Acrylic solvent adhesive. Wanted to get Weld-on from the plastic supply house, but they were out of applicators. I ended up getting some adhesive from a local hobby shop instead. Either way, the stuff actually causes the two acrylic pieces to fuse together into one, giving a nice strong joint.
- RGB LEDs. Got a few packs from eBay. Probably have more of these than I need, but wanted to have spares and extras in case my plan of one LED per space turned out to be infeasible.
- White LEDs. No sense in wasting an RGB LED on a section of the board that has a native color, like the property bars or the In Jail section. Just light those with a simple white LED and move on with life.
- Netduino microcontroller board. I’ve done raw PIC programming before and played with an Arduino a bit, and this time I’m going to try something different. A coworker was doing a project with this, but realized he needed a more powerful board, so I got this from him at a discount. May as well see if it’ll do the job I want!
- Two line LCD display. Rather than have a huge switch bank, we want to reduce the number of controls needed for this. To do that, we’ll need to provide user feedback about what those controls are doing. Two lines of LCD display seem to be quite sufficient for my purposes.
- Lots of miscellaneous electronics parts. I’ve been projecting for a while now, so there’s lots and lots of goodies in my bins already. Many of them should be useful in this process.
I also have picked up a couple of plastic-specific saw blades for my table saw and miter saw. They’ve worked reasonably well so far, but I’m hoping that I’ll learn even more about how to best use them to get nice, solid, clean cuts in this material. The less sanding and edge-polishing I have to do, the better.
The Best-Laid Plans
So having “helped” build a lighted board before, what do I want to get out of a newer board now? Well, there were several problems in the original that I’d like to overcome, and there are many features that simply weren’t within what we could reasonably accomplish given the technology that now seem possible.
So, technology aside, what were the big design flaws last time around? Here are the ones that seemed most obvious to me.
- Light leakage between spaces
- Dark areas at the top and bottom of each space (where the wood support for the track blocked light)
- Uneven space sizes/shapes
- Poor felt quality/poor logo quality
There’s plenty of other problems as well, both in original concept and execution, but I’ll let those pass. It was something fun for my Dad and me to do together. I actually have a newborn boy (which is why this build is going to take much longer than it otherwise might need to) but I just can’t bear to put the idea on a shelf for as long as it would take for him to understand and enjoy what’s going on. (Once he’s older, I’ll show this to him and ask him what other ideas he’d like to see come to life!)
With those problems in mind, what new features are possible given the current state of technology?
- Multicolor LED space lighting
- Independent property/color bar lighting
- Not having a huge bank of 40 switches to control everything
- Not using electrical tape to secure wire connections
An ambitious project to be sure, and the most complicated build I’ve done to date. (I suppose the IIDX controller was pretty complex, but this will probably be more difficult even than that.) So what materials and techniques shall we use to accomplish these goals?
- Solid black acrylic space dividers to reduce/eliminate light leakage and provide visible lines
- Translucent white acrylic panels for each game space to diffuse light evenly
- Thin or transparent supports for the spaces to eliminate dark edges
- RGB LEDs for each space to provide a wide variety of possible colors
- Independent white LEDs on each colored property bar and the In Jail space
- Microcontroller brain to run everything using a more limited control set
- LED driver ICs so we don’t need to have 160 or so individual digital outputs from the microcontroller
Several problems are not yet figured out, but I’m assuming I’ll be able to tackle those once I figure out what they are. Should be fun (and frustrating)!
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