Hurray! I have finally finished creating my infinity mirror. It's taken a while because I'm easily distracted, but it's done now. (See also Part 1 and Part 2 of this miniseries.)
Before we plunge into the fray, please note that that there's a video at the end of this blog showing this little beauty in all its glory. Even if you are short of time, you should take a moment to take a look. Now, back to the plot...
As you may recall, an infinity mirror involves a relatively thin enclosure (frame) with a full mirror at the back and a partial mirror (or a half-mirror or one-way mirror) at the front. Following my previous experiments, I decided that the optimal distance between the back mirror and the front mirror for my purposes was 1 inch. With regard to the width and height of my mirror, this was easily determined by the fact that I happened to already have a one-way mirror in my possession—and this mirror was 12" x 12"—so everything else was derived from these measurements.
My first step was to wander down to my local Lowe's store to purchase a 12x12 piece of full mirror. I also purchased a bunch of 12x12 pieces of regular 1/8-inch-thick glass for some additional experiments as discussed a little later in this column. Next, I commenced construction of the frame as illustrated below:
I built this out of strips of 3/4" wide wood. I decided to give myself 1/4" lips upon which to rest my mirrors (thereby leaving me with an 11.5" x 11.5" open area in the middle), and then added an extra 1/32" to this dimension to give myself a bit of wriggle room. The following image shows these pieces of wood just after they had been cut. The next step was to glue and nail them together and paint them black.
Of course, the thing that really makes an infinity mirror so cool is the little light sources you place on the inside of the frame between the front and back mirrors. For this project, I'd already decided to use NeoPixel Strips from Adafruit; in this case, I'm using the type with 60 tri-coloured LEDs per meter:
Now, I could simply have wrapped the NeoPixel strip around the inside of the frame and left it at that. However, I intend to experiment with different lighting effects, like having individual LEDs light up in each of the corners and move around the frame in synchronisation. This meant that I would need to have the same number of LEDs on each side of the frame. It turned out that I could fit 17 LEDs on each side, with a tiny extra gap in the corners, so I cut four 17-LED pieces off my NeoPixel strip.
Any project like this is a learning experience. If I decide to create another infinity mirror in the future (and I do have some rather cool ideas in this direction) I will do some things differently. For example, I decided to attach my NeoPixel strips to the frame using superglue. When I attached the first strip, I simply stuck it on and weighed it down, as discussed below. Unfortunately, the strip slid around a little on the glue, so it ended up being a tad out of true. This wasn't really significant, but it's the look of the thing and my professional pride that's at stake. If anyone ever opens this up in the future, I want them to say, "Look how perfect this is," not "Well, that strip is a little skew-whiff, isn't it?"
The bottom line is that, following the issues with the first strip, I used a few pieces of painter's masking tape to hold the future strips in place while the glue dried, as illustrated below.
It's a little difficult—not to mention boring—to hold a strip in place by hand while the glue dries. So I cut myself a piece of wood from the spare offcuts I have lying around in the garage. The idea was that this wood would press all of the LEDs down simultaneously:
The problem is that this wood is pretty light, and that rascally piece of strip wanted to raise parts of itself off the frame, so I quickly whipped up a cunning solution:
The two books in the foreground are used to bring us up to the same height as the top of my wooden strip. Then I placed a third book such that one side was resting on the wooden strip and the other side was resting on the first two books. Note that the first two books are placed some way from the frame, thereby increasing the leverage afforded by the brick that I placed on the third book above the wooden strip. (It's amazing how often bricks make an appearance in my projects.)
I gave each strip about 45 minutes for its glue to set before moving on to the next strip. (Perhaps I should note that I also only placed small dabs of glue between each pair of adjacent LEDs—I don't know whether it matters or not, but I prefer not to get any glue on the copper terminal linking the LEDs.)
The next task was to solder small wires in the corners linking each set of strips. Although there were only three wires per corner (5V, 0V, and the signal wire), this turned out to be a complete pain in the tukas. This is something else I will do differently if I choose to build anything similar in the future. It would have been a heck of a lot easier to perform the soldering outside the frame. I usually do this sort of thing by marking up a template on paper and then constructing things to match the template.
Consider the two images below, for example. These illustrate the process I employ to create wires for use on my Screw-Block Proto-Shield for Arduino. The first image shows my pencil sketch on paper, while the second shows me bending a piece of solid core wire to meet the sketch.
Suffice it to say that I wish I'd used this sort of technique when creating my infinity mirror. This was especially true when I finally powered things up and discovered that the fourth and final strip of LEDs in the chain didn't work. After a bit of probing with a multi-meter to check that the power and ground and signal wires were all connected correctly and there were no shorts, an oscilloscope revealed that the output signal from the last element in the third strip was extremely weak and had embarrassingly low amplitude.
The most likely source of the problem is that I zapped something with electro-static while handling things. It's my own stupid fault. I've become somewhat lax with my anti-static protocol in recent times (I'm going back to using full ESD precautions from hereon-in). This output remained weak, even after the signal wire linking the third and fourth strips was removed, so I knew for sure that the last LED in the third strip had to be replaced.
The problem was that it might have been my zapping the first LED in the fourth strip that caused the last LED in the third strip to have problems (if you see what I mean). The end result was that I decided that—rather than undergo a time-consuming step-by-step investigation—it would be easier to simply replace both the last LED in the third strip and the first LED in the fourth strip and have done with it.
"I'll use superglue and the LED strips won't go anywhere," I said to myself, happily, when I was initially attaching the strips to the frame. "I used superglue: The LED strips aren't going anywhere," I said to myself, sadly, when I realised I needed to replace them.
Fortunately, it turned out to be relatively easy to snip the strips to isolate the two problematic LEDs and to then lever them out with a sharp knife. It then took only a couple of minutes to insert the replacement LEDs into the chains and connect everything together. You can only imagine my delight when I powered everything up and it worked! It was time for me to perform my happy dance, which is what I did (be afraid, be very afraid).
But wait, there's more... As I mentioned earlier, I already had a one-way mirror in my possession, but these little rascals tend to be a tad expensive. When I originally commenced this project, I looked around on the Internet and saw that a number of people said you could use regular glass with automotive tint applied to give a reasonably good partial mirror. This explains why I purchased several pieces of 12x12 standard glass, because I then applied a variety of automotive tints to them. Some of these films were just tinted, while others were both tinted and mirrored.
When using my expensive one-way mirror, I could see about 14 levels of reflection in my infinity mirror. Most of the automotive tints were too dark or provided a smaller number of reflections. However, one of my tinted films (my notes have this down as "20% silver") looked better and provided 18 levels of reflection. The end result is shown in this video, which I just uploaded to YouTube:
Note that the painter's masking tape in the four corners is just there to hold the front mirror in place until I've finished messing around, at which time I'll replace it with a nice picture-frame. I have to say that building this little scamp has been a lot of fun. It really does look mega-cool—much cooler than the video above might suggest, because the human eye is an amazing thing, and you can see many more reflections, and the colours look way better in the real world.
Generally speaking, my son Joseph and my wife Gina the Gorgeous aren't tremendously interested in my electronics hobby projects. When I finish something, I'll call Joseph over to take a look, and he will try to appear interested and pat me on the shoulder and say "That's very nice, Dad," and then he'll return to texting his friends. Gina is much the same. In the case of this infinity mirror project, however, they were both effusive in their praise—and they actually seemed to mean it—so I'll count this as a major win.
I'm looking forward to playing around programming different effects into the infinity mirror. And all of this is, of course, paving the way for my latest-and-greatest Max's BADASS Display project. Meanwhile, I welcome any questions and comments.
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用户1406868 2015-12-18 04:13