If you’re been following along here, or especially on the “Jeremy Cook’s Projects” YouTube page, you might have noticed that I’m on a bit of a lighting kick. This started with my infinity mirror (which was fun, and I have more plans for it), but then morphed into a few other projects involving non-programmable LED strips.
I purchased a reel of this type of strip (Amazon) several weeks ago, and after coming back to them found that they were really excellent. You can cut them into sections of lights in multiples of three, and they have adhesive on the back, so you simply place them where they are needed and they stay. Another interesting “feature” is that even though they nominally require 12 volts to operate, they work quite nicely with a 9 volt battery.
The Infinity Coaster
Incidentally, a 9 volt battery fits inside a piece of 2×4 cut out with a hole saw along with a microswitch. I had this, along with pieces of one-way mirror in my garage, so after some creative fixturing and woodworking, I had what I call an “infinity coaster.” When you set a drink on it, it engages the microswitch, completing the circuit and giving the illusion of lights stretching to infinity inside of it. As shown in the video, it looks nice, though a coaster over 1 1/2 inches thick still has some room for improvement.
A Translucent Light Up Coaster
I’m not exactly sure when inspiration for this hit, but after working with these excellent lights (and having plenty left over), I had the idea to use pieces of translucent plastic separated by a spring to form a switch. Inside, I could put four 3 volt CR2032 batteries (Amazon) which, when connected in series, would give me a full 12 volts of electrical potential.
As things materialized, I went back and forth about how to integrate the spring into the design, most likely with some sort of screw setup. I eventually decided to try simply using hot glue, as it would hopefully act as a spring when a cup was placed on the coaster. This worked, but the amount of force that the cup put on the coaster wasn’t always enough to cause it to switch. To help this, I routed out material on the top piece, allowing the plastic itself to flex more. It’s still not totally consistent, but works well enough with a full drink.
Besides spring inconsistency, one major flaw in my design was how I had the original circuit laid out. This can be seen in the image above, or around 3:00 in the video. Per the diagram, it’s easy to see that the first circuit, seen on the left, isn’t really much of a circuit at all, at least not involving all four batteries. Once I realized what I’d done, I redid the drawing of the top and bottom halves of the coaster, making the connection “trenches” a little deeper and square so I could change the circuit around as needed.
Once this change was made, it worked quite well, though depending on how everything is situated inside of the coaster, it may take more or less force to turn the lights on. Perhaps it only goes on for 20 ounces of water, or at other times it might be much less.
Perhaps something like this could be used in restaurants to tell servers when a drink is nearly empty. On the other hand, that might look a little goofy, but not much more than kiosks at every table as we are starting to see now!