Projecting a line with LEDS

Hi

I apologise in advance if what I a describing in this post is very naive.

I would like to have a line of LEDS, for example 10. Which project a visible line at a distance of 10m, this line should be 2.5cm wide. The LEDS I am using will depend on what power will need to be used to achieve this goal, the line should be visible under daytime ambient light. I presume some kind of lens will be needed, a low power diverging?

As a reference point the type of line I am attempting to produce is (http://www.gizmag.com/xfire-bike-lane-safety-light/24282/), although I will be using a line of LEDS instead of a single one.

Thanks in advance :) Alex

That system uses lasers. Regular LEDs would probably have a too wide angle for your purpose.

The pictures show the system used at night, and if you look more closely, the cyclist is not riding, he is stationary and judging by the sky, the camera exposure is pretty high, leading me to believe the entire thing is misleading and not nearly as powerful as it would need to be, even during the night.

Under direct sunlight those lines would not be visible at all. You would need many watts to produce a visible line 2,5 cm wide and 10 m long on a sunlit surface. If you intend to put this on a bicycle, I'd say your project is not feasible

Yeah, they use lasers and those magic diffraction things to project lines usually (easier than doing it with lenses). I don’t think you could get a decent line out of leds, no matter what lens and how many watts you put behind it.
I normally consider “needing to use a lens” as a project killer. They need to be mounted precisely and sourced from somewhere. Unless you can find mounts and lenses that happen to be just right, you’re sol

Thanks for the analysis of the other product, you raised some interesting points. To clarify on what I am trying to achieve, I would like to create a line that is a circle with a width of roughly 2.5cm. The circle will have a radius of 2m, and the light source will be situated 1m above the ground, due to Pythagoras's theory the light will have to be projected 9m. I originally considered using a strip of LEDS, however your comment is making me reconsider. What about a lamp inside a dome, which has a strip cut out which the light would be projected from?

No you need some way to project an image and the only way to do that without coherent light is to use a lens.

Using a lamp in a dome, with a lens/es running along the circumfrence work?

You should only use one lens if you want a continuous image. However if you are having to ask about this then I suspect it might be too much for you. You will need a special lens to be manufactured for you.

So if I had a circular continuous lens manufactured, with the correct focal length. What would be the best type of light source to use?

A strip light, like a long florescence tube.

Would LEDS be possible, as they are preferable due to their low power consumption.

bexx123: Would LEDS be possible, as they are preferable due to their low power consumption.

If you use LEDs you would have to use a high density strip and put diffusers between the LEDs and the lens. LEDs would take more current than a strip light.

So a strip light would be able to produce the same amount of light as LEDS, using less current? If so, with strip lights, what does this category cover? Just fluorescent tubes?

So a strip light would be able to produce the same amount of light as LEDS,

Never said that.

using less current?

I did say that.

You can get more intense light from an array of LEDs arranged in a strip, but you need that good diffuser and that cuts down on the light.

So theoretically the led strips would be more power efficient than the fluorescent tube, however practically due to the fact that a diffuser would need to be used on the LEDS, the fluorescent tube is more power efficient.

Within the strip light category, would fluorescent tubes be the best suited to this task? Also other than the construction and alignment of the lens, are there any other main obstacles?

Thanks for your help

Hi, What is the application? What is the purpose of a ring of light?

Tom.... :)