Looking to build a small "sky-laser"

[RoshKruv]

Hi,

I want to build a small "sky-laser" to locate near my tent at festivals.
I will use 2 X 12 V batteries, 7.2 Ah each (total 14.4 Ah @ 12V) so i think 3-10 W laser could be good.
I have a voltage adapter so i can use any voltage necessary.

Could you recommend a specific laser diode to use for that purpose? i don't care about the color. the cheaper it is the better.
I would also need a large diameter lens in order to expand the beam radii, so if you could recommend that too it would be great.

Any information that could help my project would be great!

Thanks !

 

[Nae K]

On a post where a user was looking for a laser to use as a signal someone recommended a search light. And I think that could work for you but those take a lot of power.

 

[Immo1282]

Hi RoshKruv, Happy Christmas if you celebrate it

Before i go on, can you confirm you want to leave a 3-10W laser unnatended pointing into the sky? I cannot stress enough to you - this is a terrible idea and I would investigate alternative methods of locating your tent. I'm going to list a few of the dangers/Legal issues of this, and suggest a couple of alternative thoughts, and I hope you take my comments on board before you hurt yourself or others.

Powerful lasers are a serious eye hazard to people on the ground and in the air - if your laser ended up accidentally pointing at people at the festival, you could be responsible for the permanent blinding of many many people. At that power level, all it takes is a fraction of a second of exposure to burn a hole in someone's retina that'll never heal.

In addition to this, pointing lasers into the open sky is not something to be done lightly as airplanes and other air traffic can also be at risk from the same eye hazards as on the ground. A highly visible laser also reveals the location of the user very well, so expect visits from law enforcement or festival security damn quick if you're caught using something like this.

On a practical laser note - the most visible colour is green - and the most powerful diode available in this colour is rated for 1W - but this doesn't come cheap, as its usually around $150 for a bare diode, excluding any driver circuitry which you will need. Your voltage converter is no good unless it can operate in constant current mode and provide very clean power. A 1W NDG7475 will appear brighter than any single diode avaliable - a 7W NUBM44 for example will appear around 75% as bright as 1W of green.

My suggestion for you if you're set on a beam of vertical light is to look at a way of focusing a powerful LED flashlight to infinity in a narrow beam - but this is still really not a very good solution. Powerful LEDs and Lasers alike eat power and kick out a lot of heat - a diode like the NDG7475 will need a significant amount of heatsinking and possibly active cooling if you want it to be on constantly - and it's going to decimate pretty much any battery that you have to power it with. Is there not a GPS based solution you can utilise?

As an aside, the members of this forum are generally more inclined to help if new members post their rough location (helps us know what's legal in your country) interests and experience in the Welcome subforum

 

[Nae K]

Hi RoshKruv, Happy Christmas if you celebrate it

Before i go on, can you confirm you want to leave a 3-10W laser unnatended pointing into the sky? I cannot stress enough to you - this is a terrible idea and I would investigate alternative methods of locating your tent. I'm going to list a few of the dangers/Legal issues of this, and suggest a couple of alternative thoughts, and I hope you take my comments on board before you hurt yourself or others.

Powerful lasers are a serious eye hazard to people on the ground and in the air - if your laser ended up accidentally pointing at people at the festival, you could be responsible for the permanent blinding of many many people. At that power level, all it takes is a fraction of a second of exposure to burn a hole in someone's retina that'll never heal.

In addition to this, pointing lasers into the open sky is not something to be done lightly as airplanes and other air traffic can also be at risk from the same eye hazards as on the ground. A highly visible laser also reveals the location of the user very well, so expect visits from law enforcement or festival security damn quick if you're caught using something like this.

On a practical laser note - the most visible colour is green - and the most powerful diode available in this colour is rated for 1W - but this doesn't come cheap, as its usually around $150 for a bare diode, excluding any driver circuitry which you will need. Your voltage converter is no good unless it can operate in constant current mode and provide very clean power. A 1W NDG7475 will appear brighter than any single diode avaliable - a 7W NUBM44 for example will appear around 75% as bright as 1W of green.

My suggestion for you if you're set on a beam of vertical light is to look at a way of focusing a powerful LED flashlight to infinity in a narrow beam - but this is still really not a very good solution. Powerful LEDs and Lasers alike eat power and kick out a lot of heat - a diode like the NDG7475 will need a significant amount of heatsinking and possibly active cooling if you want it to be on constantly - and it's going to decimate pretty much any battery that you have to power it with. Is there not a GPS based solution you can utilise?

As an aside, the members of this forum are generally more inclined to help if new members post their rough location (helps us know what's legal in your country) interests and experience in the Welcome subforum

Also he mentioned HIS tent at festivals, and I'm not sure if some have rules on lasers so finding a way to keep a powerful LED flashlight cool could be the better option like you said.

 

[paul1598419]

This is not unlike many ideas we get from new members here. You should never have a laser, unattended, firing in public as it is a dangerous hazard to others. Many people come here with ideas that are not at all workable and turn out to be just the latest in the realm of awful wet dreams. You could do the same thing with a powerful LED flashlight that is focused to be a spotlight. This is by far a much better idea and would likely work better for your purposes than a laser would.

Lasers seem to be many people's big "wow" idea to do something that has much better options to accomplish it than any laser. High powered lasers are especially dangerous and you would be arrested in short order if you tried this in a public place. a GPS would be a much better option, as would a flashlight/spotlight.

 

[Nae K]

This is not unlike many ideas we get from new members here. You should never have a laser, unattended, firing in public as it is a dangerous hazard to others. Many people come here with ideas that are not at all workable and turn out to be just the latest in the realm of awful wet dreams. You could do the same thing with a powerful LED flashlight that is focused to be a spotlight. This is by far a much better idea and would likely work better for your purposes than a laser would.

Lasers seem to be many people's big "wow" idea to do something that has much better options to accomplish it than any laser. High powered lasers are especially dangerous and you would be arrested in short order if you tried this in a public place. a GPS would be a much better option, as would a flashlight/spotlight.

I just re read the post, I failed to realize he was trying to LOCATE his tent not just have a laser for show at his tent. GPS is for sure the best option.

 

[RoshKruv]

Hi RoshKruv, Happy Christmas if you celebrate it

Before i go on, can you confirm you want to leave a 3-10W laser unnatended pointing into the sky? I cannot stress enough to you - this is a terrible idea and I would investigate alternative methods of locating your tent. I'm going to list a few of the dangers/Legal issues of this, and suggest a couple of alternative thoughts, and I hope you take my comments on board before you hurt yourself or others.

Powerful lasers are a serious eye hazard to people on the ground and in the air - if your laser ended up accidentally pointing at people at the festival, you could be responsible for the permanent blinding of many many people. At that power level, all it takes is a fraction of a second of exposure to burn a hole in someone's retina that'll never heal.

In addition to this, pointing lasers into the open sky is not something to be done lightly as airplanes and other air traffic can also be at risk from the same eye hazards as on the ground. A highly visible laser also reveals the location of the user very well, so expect visits from law enforcement or festival security damn quick if you're caught using something like this.

On a practical laser note - the most visible colour is green - and the most powerful diode available in this colour is rated for 1W - but this doesn't come cheap, as its usually around $150 for a bare diode, excluding any driver circuitry which you will need. Your voltage converter is no good unless it can operate in constant current mode and provide very clean power. A 1W NDG7475 will appear brighter than any single diode avaliable - a 7W NUBM44 for example will appear around 75% as bright as 1W of green.

My suggestion for you if you're set on a beam of vertical light is to look at a way of focusing a powerful LED flashlight to infinity in a narrow beam - but this is still really not a very good solution. Powerful LEDs and Lasers alike eat power and kick out a lot of heat - a diode like the NDG7475 will need a significant amount of heatsinking and possibly active cooling if you want it to be on constantly - and it's going to decimate pretty much any battery that you have to power it with. Is there not a GPS based solution you can utilise?

As an aside, the members of this forum are generally more inclined to help if new members post their rough location (helps us know what's legal in your country) interests and experience in the Welcome subforum

Thanks for your response, i may have to re-think the idea for safety reasons, but i do want to point out that my goal is to expand the laser beam to a diameter in which the energy density won't be dangerous anymore by using a lens. (even 3-5 W laser won't be so dangerous if the beam diameter is 60 [cm]) this way i can achieve the visibility and reduce the risk.

What's a GPS though ?
(I'm located in Israel)

 

[Nae K]

Thanks for your response, i may have to re-think the idea for safety reasons, but i do want to point out that my goal is to expand the laser beam to a diameter in which the energy density won't be dangerous anymore by using a lens. (even 3-5 W laser won't be so dangerous if the beam diameter is 60 [cm]) this way i can achieve the visibility and reduce the risk.

What's a GPS though ?
(I'm located in Israel)

GPS(Global Positioning System) is think of if you have ever used google maps or apple maps for directions on where to drive that is an example of GPS.

 

[RoshKruv]

GPS(Global Positioning System) is think of if you have ever used google maps or apple maps for directions on where to drive that is an example of GPS.

Haha sure i know, i though it was some kind of short for some kind of laser.
I'm not doing all this to locate my tent! i want to do it for artistic reasons, i want to create a big diameter laser beam that you can see for far away, and to locate it on top of some kind of wooden tower we will build (as a Burning-man camp for example)

 

[RoshKruv]

Hi RoshKruv, Happy Christmas if you celebrate it

Before i go on, can you confirm you want to leave a 3-10W laser unnatended pointing into the sky? I cannot stress enough to you - this is a terrible idea and I would investigate alternative methods of locating your tent. I'm going to list a few of the dangers/Legal issues of this, and suggest a couple of alternative thoughts, and I hope you take my comments on board before you hurt yourself or others.

Powerful lasers are a serious eye hazard to people on the ground and in the air - if your laser ended up accidentally pointing at people at the festival, you could be responsible for the permanent blinding of many many people. At that power level, all it takes is a fraction of a second of exposure to burn a hole in someone's retina that'll never heal.

In addition to this, pointing lasers into the open sky is not something to be done lightly as airplanes and other air traffic can also be at risk from the same eye hazards as on the ground. A highly visible laser also reveals the location of the user very well, so expect visits from law enforcement or festival security damn quick if you're caught using something like this.

On a practical laser note - the most visible colour is green - and the most powerful diode available in this colour is rated for 1W - but this doesn't come cheap, as its usually around $150 for a bare diode, excluding any driver circuitry which you will need. Your voltage converter is no good unless it can operate in constant current mode and provide very clean power. A 1W NDG7475 will appear brighter than any single diode avaliable - a 7W NUBM44 for example will appear around 75% as bright as 1W of green.

My suggestion for you if you're set on a beam of vertical light is to look at a way of focusing a powerful LED flashlight to infinity in a narrow beam - but this is still really not a very good solution. Powerful LEDs and Lasers alike eat power and kick out a lot of heat - a diode like the NDG7475 will need a significant amount of heatsinking and possibly active cooling if you want it to be on constantly - and it's going to decimate pretty much any battery that you have to power it with. Is there not a GPS based solution you can utilise?

As an aside, the members of this forum are generally more inclined to help if new members post their rough location (helps us know what's legal in your country) interests and experience in the Welcome subforum

Can you recommend of a specific model with this 1W NDG7475 520 nm laser diode?
with heat sink and driver?
i think you convinced me into it, ill just use this 1W laser with some beam extender and i think i will get what i'm looking for
and be on the safe side.

how's this product?
https://www.alibaba.com/product-det...spm=a2700.7724857.normalList.6.be268616A2eKRN

 

[Immo1282]

even 3-5 W laser won't be so dangerous if the beam diameter is 60 [cm]

Glad you're open to our suggestions - but if the beam diameter is 60cm, its not going to be very visible at all. Visibility of the beam is best along the rough axis of the beam, and really not so much from distance. The only reason a laser beam is visible is because of the power density of the beam. Spread 1W of 520nm laser light over a large diameter beam and it'll barely be visible.

I'm afraid to dissapoint you but if a beam's highly visible from the side in clean air, it's going to be dangerous to the eyes of the people around. Not sure I'm comfortable with this project in all honesty but here's what you'll find out from reading stuff here...

A good source for diodes, drivers and all associated is forum member DTR's shop (albeit US based) His prices are a bit higher than you'll find on alibaba/eBay but his service is worth it IMHO.

 

[paul1598419]

GPS stands for global positioning satellites. There are ~24 of them in orbit around the earth with four of them within eye-shot from anywhere on the planet. Using the signals that they produce allows a GPS systems to locate any place on the planet to within a foot or so. I have a Garmin system I purchased new over four years ago that can tell me how to get around anywhere in North America. You can get them for finding any place even in undeveloped places anywhere in the world and is really the best option you would have for finding your tent in a tent city situation. It would work much better than any laser system you could think of to use.

 

[steve001]

Hi,

I want to build a small "sky-laser" to locate near my tent at festivals.
I will use 2 X 12 V batteries, 7.2 Ah each (total 14.4 Ah @ 12V) so i think 3-10 W laser could be good.
I have a voltage adapter so i can use any voltage necessary.

Could you recommend a specific laser diode to use for that purpose? i don't care about the color. the cheaper it is the better.
I would also need a large diameter lens in order to expand the beam radii, so if you could recommend that too it would be great.

Any information that could help my project would be great!

Thanks !

Look up "Fat beam" laser. That might be an option. The caveat is as with any light source seen at a 90° angle from the beam said beam must have high output especially in clear air. Moisture (humidity) or particulates will increase visibility. Green would be the best choice.

 

[hakzaw1]

That was what I thought.. buy 4 or 5 green fat beam modules. (myb 80 to100 mW)
I advise against leaving even them unattended.
.plug and play. off 18650 3.7vdc Li-ions.

If its hot there you may need active cooling or make a way to allow some to rest while others are working--a duty/rest cycle. additional heat sinking advised. Other Wavelengths look great but only green has a chance of you seeing it aimed up and from far away.

OR get a flag and a long flag pole

There are now laser search lights..

Many members here have built laser flashlights.... BUT NOT ON PURPOSE lol
(like me)