Questions tagged [lighting]

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7
votes
1answer
126 views

LED Lumen Calculations

I am using an LED as a point source for a school project. I have two questions in regards to the LED(s). I know that light follows the inverse square law when measuring perceived brightness, but all ...
4
votes
1answer
414 views

Alternatives to laser line?

I'm trying to project a very thin line at a low angle over some surface defects (peaks and troughs). The scale is ~20mm square, but the defects can be sub-mm (0.2 - 1.0mm). I am currently using a line ...
4
votes
2answers
136 views

What plastic material blocks the most amount of light?

If I have a grid array of LED's surrounded by roughly 0.7mm thickness plastic walls. What material at this thickness would prevent light bleed side to side so that individual LED's can light up but ...
3
votes
4answers
1k views

How do I measure the brightness of a light bulb?

I am working on a science fair project. My question is if electricity moves better through a thin wire or a thicker wire. I need to collect data and make charts, and the thing I want to measure is the ...
3
votes
1answer
87 views

Street Light Arrangement Method

Hello I am a high school student and I am curious about how street light is arranged along the road. Is there government laws to install street light on the road or is the arangement of the street ...
2
votes
3answers
39 views

How can I achieve good diffusion from an LED light source?

I have a light fixture which is designed as three rows of LED light strips. The problem is that the LEDs appear as brilliant points of light. In the fixture I want to diffuse this light so that it ...
2
votes
2answers
657 views

How to predict shadows of a house (3D modeling + sunlight)?

Imagine a house/building, seen from outside, at sunrise. As the the sun moves in the horizon, a) the shadow of the house is displaced/deformed, and b) some faces of the house have more/less sunlight ...
2
votes
3answers
212 views

Animated light box signs

In the old days there was a type of sign/light you would find in bars and restaurants which was animated. It would be a lit scene usually of water, like a lake with a waterfall, and by some means it ...
2
votes
1answer
63 views

Where to acquire / create LED optics

I'm working on a few projects that require lenses to focus LED light flashes, similar to those lenses used by police lights (TIR lens) and other strobe traffic lighting utilizing Fresnel lenses. I've ...
1
vote
2answers
73 views

Why aren't driving roads also illuminated from the ground up, like airport runway lights?

Compared to its Mar 2016 article, the Nov 29 2018 article by the Insurance Institute for Highway Safety proclaims that "headlights improve, but base models leave drivers in the dark" and ...
1
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2answers
978 views

LED color change in extreme cold

Which part of the LED is affected when it is exposed to liquid nitrogen? I have seen experiments showing LED's brightness increasing and color shifting, when the LED is submerged in liquid nitrogen. I ...
1
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3answers
475 views

Does temperature affect the colour of the light emitted by an LED?

Suppose you have an LED that emits a spectrum of colours such that the resultant colour emitted is white. Will changing the temperature if the LED itself change the composition of the light's colour ...
1
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2answers
123 views

Light bulbs with highest energy efficiency [closed]

Most specs for light bulbs list luminous efficiency (or, more accurately sometimes, luminous efficacy) but not energy efficiency. Luminous efficacy tells you how bright the light is as observed by a ...
1
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1answer
82 views

Relations/Equations to do with light diffusing materials

I recently started as designer at a making custom signage (small signs viewed up close, so there are lots of sizing limitations) and none of the other designers have any solid rules to rely on for ...
1
vote
2answers
434 views

Diffuse uniform LED back lighting

Good morning/afternoon/evening, I am working on a project in my spare time, and was wondering how this effect is created. and I am going to assume this is more than just a cutout with an LED behind ...
1
vote
1answer
41 views

Which optical filter to use for flat black non-glare aerospace indicator?

I am currently designing a LED light indicator for use in an aircraft cockpit replica. I’m asking for expert advice on the type of lenses to use in order to get a result similar to shown pictures. ...
1
vote
1answer
40 views

Passive Infrared Sensors (PIR) spectrum and reflections

I have a common PIR occupancy sensor (Lutron MS-OPS5M-WH). I am trying to get the sensor to cover an irregular-shaped room. I could expand the field-of-view of the sensor to cover the whole room by ...
1
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0answers
53 views

Rube Goldberg, twisting in a lightbulb

For my rube golberg project I have to twist a lightbulb in and have it turn on. I have seen different videos on how they do it but they never explain it and most of the videos are blurry. We can't ...
0
votes
3answers
82 views

Is there a way to determine the colour information of light emitted from an LED?

Say you have an LED light that emits green light. Are there sensors out there that could accurately determine the colour information of the green light? Such as the relative values of red, blue and ...
0
votes
1answer
53 views

Lightning strike and metal structures in garden

I am worried about metal posts (support structures for plants) placed in garden and danger from lighting strikes. Posts are 3 meter long rebars and they are about 1,5 m driven into ground. Around ...
0
votes
1answer
48 views

What has changed since the 1990s that made "LED lights" possible?

I keep seeing all kinds of objects now having small but very bright LED lights in them, seemingly never burning out, requiring almost no batteries/power, and extremely durable. I remember being a ...
0
votes
2answers
456 views

how to implement autofocus for video projector

I have a modified pico video projector that I need to add an autofocus to. The focusing ring already has a fast stepper motor added to it. If the focus had to be done on the middle of the projection ...
0
votes
1answer
75 views

LED controller to control individual RGB diodes remotely?

I'm working on a project which utilizes an iPad to change colors of individual lights in array of ~200 RGB LEDs. I have little knowledge of large-scale LED configurations and could use some direction. ...
0
votes
1answer
36 views

Thickness of a 3d print general purpose plastic/PLA 230 V ~ isolator?

I'd like to design a minimal thin light switch which holds an illuminant with standardized socket, e.g. E14, E27, and has itself such a socket to be screwed in a support and a switch which will be ...
0
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2answers
115 views

Activating lights using a motion sensor?

I was wondering how I would configure some sort of setup to get lights like this turn on a timer once activated by a motion sensor. I want them to turn on for about 15 seconds and then turn off once ...
-1
votes
1answer
44 views

Why HMMWV's lights aren't located at the edges?

Hummvee has front lights located far from edges, closer to each other. That makes it harder to see edges of the vehicle in the dark.
-1
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2answers
216 views

What is the significance of curvature in the arm of a streetlight?

I have been trying to find out the significance of the usual streetlight design - Why is there curvature of the arm holding the bulb of the light? I have been unable to any reason as to why it may be. ...