# Questions tagged [lighting]

The tag has no usage guidance.

27 questions
Filter by
Sorted by
Tagged with
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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. ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
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. ...
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 ...
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 ...