This is a list of my favorite LED diffusion ideas, which I hope will provide you with some sparks of inspiration for creating your own next-level illumination. Examples and links are provided for each!
Step 1: Paper-Lined Shadow Box
We’ll start out with an easy one: just start out with a box, either homemade or an easily found shadow box frame, for example, and line the inside with plain printer paper.
In my WiFi Weather Display project, for example, I broke the shadow box up into sections with a folded piece of corrugated cardboard. Then I taped some pixel strips to the back, shining into each triangle shape. In the Arduino code I control the color of each section of the pixel strand to create abstract weather patterns. Notice how the “snowy” status has some blue and some white LEDs, as compared to “rainy” with only blue.
The simplest form of this technique can also achieve a great result, and that’s just to line the walls of the box with a single LED strip. Make the inside of the box white so the light can bounce around, and create a cutout face with the design of your choice. Learn more in my Instructable about this 2017 sign.
Step 2: Woven Fabric
Woven fabrics aren’t stretchy, so they’re easier to sew and keep flat. If you go shopping for fabric in person, bring a flashlight or use your phone’s flashlight to test how different fabrics transmit light. Some, upon illumination, will show off an interior texture that you couldn’t see from the surface. If you’re shopping online, look for lightweight synthetic woven fabrics as a starting point. Faux flowers are also made of woven fabric.
If you’re looking to smooth out letters on an LED scroller sign, the next obvious choice beyond paper is woven fabric. In the messenger bag display project pictured, I used solid white ripstop nylon to diffuse a large flexible NeoPixel display right up against the surface of the LEDs.
Step 3: Knit Fabric
Knit fabric is stretchy! Sweaters are knit, so are t-shirts. Knits can be tough to work with, but are great for diffusing LEDs! Like in the case of the pictured off-white fluffy cable-knit sweater: it diffuses the 8×8 NeoPixel matrix with an added texture that couldn’t be imparted any other way. It’s probably too thick to read numbers/letters through it, but the soft edges it gives the snowflakes are very festive.
The color changing scarf has an interior string of pixels diffused by a heavily gathered machine-knit panel. The folds of the gathered knit material were supposed to give a floral garland effect, but I think this thin grey yarn choice fell short of its goal.
Step 4: LED Underlighting
You can use backlighting in many other applications as well. Technically it’s not diffusion, since the light is reflecting off of something else, but we’ll include it in our brainstorm anyway! In my Internet Valentine project, I glued tiny sequin LEDs to the back of a tissue paper heart, and they reflect off the white card behind to give the heart a red glow. Similarly, the red illuminated button shines up at the tissue paper heart on the remote to the left, bathing the layered pedals in red light.
Step 5: Ping Pong Balls
Ping pong balls are a classic diffusion idea that is not used nearly enough, in my opinion. Cut a hole just big enough for your LED(s) (left) or cut them in half (right). Blast it with a cluster (like a NeoPixel Jewel, left) or use a single LED (right).
I live in a small studio, the main lighting for which is provided by nine ceiling spotlights (GU10 fitting), split four on one switch, five on another. When I moved in there were mostly traditional halogen bulbs in place, a couple of which were dud, but the overall effect and atmosphere was just right.
A recent French government-backed scheme provided up to ten free LED lightbulbs to households on lower incomes, so I got my quota. As nearly all the halogen bulbs have now blown, I’ve been fitting the LED ones in their place. The new bulbs are good quality, long-life and not necessarily cold white light, they have a warm-ish hue, but…
They’re so bloody bright! Coming back into my flat of an evening is like stepping into Wembley Stadium under floodlights, relocated to the Sahara Desert, at midday, during the phase of the solar system’s history where the sun expands and envelops the Earth. They’re so bright that I’m sure that when I yawn a beam shines out my arse.
What seems to be becoming a common problem with many LED bulbs now being fitted on traffic lights, metro trains, street lights and elsewhere is that they’re so bright as to cause pain in the eyes. It’s not quite that severe in my home but the ambiance is nonetheless ghastly. Every speck of dust, of which there are many, has taken on a new life and is now taunting me from the sidelines.
I’ve read that dimmable LEDs require some fiddling about for installation, and I don’t wish to purchase new bulbs anyway, I want to use the ones I’ve got. Doing some DuckDuckGoogling, I thought a popular solution to this phenomenon might exist but I’ve not turned up much. These frosted lenses are about the most relevant thing I can find but they each cost more than a typical LED bulb. I’m rather more looking for a solution of around this price that will serve all nine of my bulbs.
The aluminium circular frames that the bulbs screw into (not the sockets) are very tight so I don’t think any such glass lenses would fit anyway. The only other solution I can think of is fitting some coloured film between the frames and the bulbs, but I don’t so much want colours as I do filters. And I’m not sure of the implications for fire resistance – I wouldn’t want any such film to overheat and catch light.
Anybody have suggestions, other than just leaving half the fittings with dud bulbs (a rather ugly compromise)?
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