Need help with line generator.

[Vania]

Hi, new member here.

I need a green laser line generator. The laser will be mounted 3 feet high(1 mt), angled towards the ground to create a 164 feet(50 mts) line in front of it.

The line projected on the ground must be visible in daylight.
The laser must stay on for several hours in a row.
The line should be safe at a distance of 16 feet(5 mts) or more.
It doesn't matter that the line grows thicker as the distance increases.

(I know 5mw lasers are safe, but 5mw spread across a 164 feet line wont make it I guess)

 

[Bionic-Badger]

Well, before any suggestions are made, how much are you willing to spend?

 

[Cyparagon]

No one else is gonna ask why? I have to do it again?

WHY, op? Your problem might be entirely unrelated to lasers.

 

[Vania]

I was expecting to spend 200$ or less.

Why I need it? I want to build something like this:
BLAZE Bike Light by Emily Brooke ? Kickstarter
but for motorcycles.

But please let's stay on topic, I don't want to discuss the pros and cons of such a device.

 

[pschlosser]

Any light emitting from a registered motorized vehicle and operating on any public roadway in the U.S. has very specific and clearly documented restrictions. Exceeding 5mW will be risky, in terms of conforming to traffic laws. The Blaze Bike Light Diffraction Grating Thingy is, no doubt, in the 5mW range and I suspect would NOT be that visible during the day.

But, if you want to do it, anyway, then go for it. A simple scanner (spinning polygon mirror) like those found in bar code readers should do the trick to scan from just on front of the vehicle to 160 feet away. Choose any laser pointer to feed it that can operate continuously and add a 12v power supply (to run off the motorcycle's power.)

You may have an issue because most green laser diodes are of the DPSS (Diode Pumped) variety. DPSS are delicate. There are many a story on this forum of people dropping their green laser pointer and killing it. Also, being a Class M1 holder, I know all too well how much a motorcycle can vibrate. Unless you can address and isolate the laser from the vibration, I suspect they won't last long.

As far as being seen during the day, sure it may be seen, but I have doubts it will be very noticeable. At night, the green beam has a sharp contrast with the relatively dark surroundings. Coupled with the green being the most visible color, a green laser works effectively at night. During the day, it is still bright and efficient, but it must compete with all the light and activity of the day. Your mileage may vary.

I would start small, with a 5mW laser pointer, and see if you can get it working and set up. Then, as the laser diodes break, you can upgrade them with higher powers, until you find a power that is satisfactory.

Seeing a green laser from 160 feet away, shining on the ground from 3 feet high, and being visible during the day, will take a very high power laser. I suspect 2000mW or more. But they don't make DPSS greenies that big... yet ( I am pretty sure) The best you can hope for is 500mW and expect to pay big $$$$ and require some fancy cooling.

Now, for night only, you may find 50mW - 100mW is all you need to be effective at 160 feet. But you better make darn sure the thing doesn't shine in anyone's eyes. I for one, am doubtful you can pull this off, safely. All it takes is for a driver to complain to law enforcement, that they got zapped by the laser, and you're toast.

 

[Cyparagon]

But please let's stay on topic, I don't want to discuss the pros and cons of such a device.

But that IS on topic.

It's a silly idea from the internet's large intestine. You can't have it be visible during daytime AND be safe to other drivers.
Distracting drivers with flashy displays like that is inherently dangerous anyway.

Let's say I made a thread asking how to make a sledge hammer. Someone asks "why?" and I reply, "to toast bagels with. But lets stay on topic, I won't want to discuss the pros and cons of this method. I just want to know how to make a sledge hammer." You'd say I was batshit insane.

 

[Vania]

That's fine I'll be happy if it works only in dim light.

I may be able to hook it to the bike's high beam, to flash it only when I'm about to cross an intersection.
This is just an experiment anyway, I'll let you guys know how it goes.