7
votes
Accepted
Alternatives to laser line?
A few points that don't fit into a comment but could help you:
Get a better laser source than a 4 \$ laser diode. "Better" means a laser with higher beam quality. When you look at a laser's ...
- 1,863
2
votes
Diffuse uniform LED back lighting
On first inspection this looks to be done with diffuser placed above an LED light source. That will expand the cone of light generated by the LED to cover a larger area. As for the shape, it looks to ...
- 632
2
votes
Accepted
Light bulbs with highest energy efficiency
By your metric, a electrically-heated black body radiator in vacuum would be very efficient.
Incandescent bulbs are close, but run at high temperatures to make (at least some) visible light. However,...
- 11.4k
2
votes
Accepted
LED color change in extreme cold
The LED is a semiconductor that was designed for a certain voltage at a certain temperature. This certain voltage is called "band gap" and is set by properly doping it during manufacturing. The "band ...
- 7,904
2
votes
LED color change in extreme cold
This is a rather in-depth question but broadly speaking - The part of the LED which is affected by the liquid nitrogen is called the p-n junction. The two halves of the junction are a set distance ...
- 170
2
votes
Why aren't driving roads also illuminated from the ground up, like airport runway lights?
In ground lighting is more expensive and requires the light source to be able to be run over by all vehicles that use the road, including very heavy vehicles. Such lighting only acts a point source of ...
- 9,642
2
votes
Why aren't driving roads also illuminated from the ground up, like airport runway lights?
I would think because airports are really well maintained while regular road lights get covered in dirt, sand, mud, debris, and snow. Also, vandalism is more difficult when the lights are higher up ...
- 5,237
2
votes
Why HMMWV's lights aren't located at the edges?
The lights are mounted within specifications for positioning as required by laws in countries where they are used/sold.
Also, designers position them relating to the use the vehicle is likely to see, ...
- 15.5k
2
votes
Accepted
Relations/Equations to do with light diffusing materials
You seem to face a few issues.
First is to account for the potential to have patchiness in any one your sheets. Theoretical equations for light transmission through a system will be easiest when ...
- 2,878
2
votes
Is there a way to determine the colour information of light emitted from an LED?
What you are asking for is called a spectrometer. There are two main ways spectrometers work: with a prism or a diffraction grating. Either way, different wavelenght of light end up getting spread ...
- 11.4k
2
votes
How do I measure the brightness of a light bulb?
While an incandescent bulb can be a good visual indicator of the current and/or voltage in a circuit measuring its brightness and then converting that to numerical data is a very roundabout and error ...
- 15.2k
2
votes
How do I measure the brightness of a light bulb?
You will need to use a light meter to measure luminous intensity.
Because light is a form of radiation emitted by a source, it follows the inverse square law, where luminous intensity decreases with ...
- 9,642
2
votes
Accepted
Animated light box signs
After some more research, I found it: Scene-o-rama!
These animated water motion signs from the 1950s and 1960s work by a plastic overlayer and roll film on the underside that constantly rotates in a ...
- 1,625
2
votes
Lightning strike and metal structures in garden
Lightning often strikes at the highest point. So it's more likely to hit the trees (as they often do) than the bars. That's why lightning rods are build on high precipices, buildings, etc. ...
- 544
2
votes
Is it possible to estimate location of a source of light using single camera?
Yes, as discussed on
SO – Is it possible to measure distance to object with camera?, Finding distance to an LED
SE Physics – How the calculate distance of light source
it is indeed possible. However,...
- 369
2
votes
Transferring image from one window to another
The simplest solution would be to use a periscope. You need to be aware of a few points - mostly that light travels in straight lines and that when reflected on a mirror the angle of reflection is ...
- 10.3k
1
vote
How can I achieve good diffusion from an LED light source?
The problem is probably that your frosted surface is too close to the LEDs. It needs to be far enough away, compared to the distance between the LEDs, that a point mid-way between two of them gets ...
- 111
1
vote
What has changed since the 1990s that made "LED lights" possible?
The biggest hurdle was the white light LEDs, which were first available commercially in 1996-1997, a few years after the blue light (1994) .
The following image compares all types of lighting
An 2018 ...
- 24.3k
1
vote
How to predict shadows of a house (3D modeling + sunlight)?
Autodesk 3D Studio used to do this when I was rendering with it around years 2000 to 2005. It is not free though.
you could define one or many light sources and one or several cameras and then ...
- 22.1k
1
vote
Is there a way to determine the colour information of light emitted from an LED?
You want to do a light spectrum analysis on the led.
You can do this with a prism that will spread out the light into colors and then find where the peaks and valleys are in the spectrum.
That or ...
- 5,751
1
vote
Activating lights using a motion sensor?
Here's a product that does what you want:
Socket outlet to plug your light into
Timer settable to 10s - 4 minutes
I'm sure they'll exist with other country's plugs on them.
https://www.aliexpress....
- 426
1
vote
Activating lights using a motion sensor?
Use standard PIR sensor for common motion-activated spotlights, like these:
Open it, and find the relay inside (it will usually be the bulkiest part, likely colored blue). Disconnect the output from ...
- 6,125
1
vote
LED Lumen Calculations
Lumen (luminous flux) is irrelevant to the distance where the LED's being measured from, you can take lumen as a total light energy measured around that LED (captured by an all-rounded measuring ...
- 11
1
vote
Street Light Arrangement Method
Street lights are installed in order to provide a minimum lighting level along the roadway. Some municipalities or states or countries may have minimum lighting standards, but these often vary ...
- 171
1
vote
how to implement autofocus for video projector
U can use a mirror for feedback of the projected image and a SLR as in cameras (a piece of glass at an 45` angle to measure the difference between projected and image onthe screen and approp. adjust ...
- 19
1
vote
What plastic material blocks the most amount of light?
You want a polymer that is strong and easy to injection mold in thin sections (.7mm). Black nylon would be perfect.
- 601
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vote
What plastic material blocks the most amount of light?
A foil coated plastic would be ideal as a metallic surface prevents light bleed and is easily manufactured. The higher the density of any material the less transparent they tend to be except in the ...
- 964
1
vote
How do I measure the brightness of a light bulb?
A photo resistor or solar panel make for pretty easy/low cost light measuring solutions, but they are not super accurate and will be much more complicated than the primary project. Hook the solar ...
- 7,904
1
vote
LED controller to control individual RGB diodes remotely?
I use leds with the chip ws2812 aka neopixel and are very easy to control with Arduino. With Raspberry Pi is a bit coplex due to timing requirements.
With neopixel every led may be individually ...
- 11
1
vote
Does temperature affect the colour of the light emitted by an LED?
The answer is YES for monochromatic LEDs and "not really" for Phosphor-converted LEDs. Monochromatic LEDs can change a lot in color depending on the operating temperature, with probably the ...
- 141
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