Question's concerning Jetlasers Yamataka series.

[BobMc]

Hey Bob, you're not planning to use this in the grow room are you? :shhh:
And FWIW, a little birdy told me that lasers just ticks Bigfoot off, so keep that in mind too.

Haaa, you busted me me CE5, shucks! :crackup: and what's worse is it doesn't scare off Bigfoot! Man them critters are getting smarter every day.

 

[Encap]

If you intend to use a Yamataka as a laser dazzler be sure you know the safety aspects for the power output you choose for you Yamataka or other dazzler to avoid damaging anyone eyes.
Flashblinding does not cause permanent ocular damage. In the case of a dazzler of any given output power the question is how to determine the minimum and maximum dazzle/flashblind distances for whatever laser you are using as a dazzler??

If a beam’s power density (irradiance) from the laser source to the target to be dazzled exceeds the Maximum Permissible Exposure limit set by scientists of 2.54 milliwatts per square centimeter ocular/eye damage can occur. A beam is considered completely eye safe only if the irradiance falls below the MPE limit.

Nice ocular hazard calculator is helpful here: Laser Pointer Safety - Laser hazard distance calculator
Here is a hazard calculator app for IPhone: https://itunes.apple.com/us/app/laser-hazard-distance/id460996018?mt=8

For the reason's and math behind the calculator and other important informations see: Laser Pointer Safety - Laser hazard distance equations

Also helpful is short article by Ophir-- A Shortcut for Calculating Laser Power Density, http://www.ophiropt.com/blog/laser-measurement/a-shortcut-for-calculating-power-density-of-a-laser-beam/ and Ophir's Power Density Calculaltor: http://www.ophiropt.com/laser--measurement/power-density-calculator

If you own and/or intend to ever use a dazzler it is a 'no brainer" that you need to know and study the above information to avoid criminal and civil legal problems and most importantly to avoid permanently damaging anyone's eyes, including you own.
To do otherwise, not know what you are doing, why or how is dangerous, reckless, and irresponsible. Such behavior can result in very negative consequences, be time consuming, very expensive, and cause serious legal problems for the person dazzling.

To know the legal status of dazzlers and their use in whatever State or Country you are in is a must also.

 

[BobMc]

If you intend to use a Yamataka as a laser dazler be sure you know the safety aspects for the power output you choose to avoid damaging anyone eyes.
Flashblinding does not cause permanent ocular damage. In the case of a dazzler of any given output power the question is how to determine the minimum and maximum dazzle distances for whatever laser you are using as a dazzler??

If a beam’s power density (irradiance) from the laser source to the target to be dazzled exceeds the Maximum Permissible Exposure limit set by scientists of 2.54 milliwatts per square centimeter ocular/eye damage can occur. A beam is considered completely eye safe only if the irradiance falls below the MPE limit.

Nice ocular hazard calculator is helpful here: Laser Pointer Safety - Laser hazard distance calculator
Here is a hazard calculator app for IPhone: https://itunes.apple.com/us/app/laser-hazard-distance/id460996018?mt=8

For the reason's and math behind the calculator and other important informations see: Laser Pointer Safety - Laser hazard distance equations

If you own and/or intend to ever use a dazzler it is a 'no brainer" that you need to know and study the above information to avoid criminal and civil legal problems and most importantly avoid permanently damaging anyone's eyes, including you own.
To do otherwise, not know what you are doing or why, is dangerous, reckless, and irresponsible. Such behavior can result in very negative consequences, betime consuming, and very expensive.

Words of wisdom, Encap .

Thanks so very much for those links. Will be read and throughly studied. Much appericated. Those links could be called the instruction manual for owning laser/dazzlers and all lasers it could be useful with. :bowdown:

Nobody buys a gun wanting to use it on someone. It's the last thing any gun owner wants to do. Buying/owning a dazzler is the same thing. It just gets you another option ( non lethal ) if the other individual will not let you live it peace.

 

[steve001]

Words of wisdom, Encap .

Thanks so very much for those links. Will be read and throughly studied. Much appericated. Those links could be called the instruction manual for owning laser/dazzlers and all lasers it could be useful with. :bowdown:

Nobody buys a gun wanting to use it on someone. It's the last thing any gun owner wants to do. Buying/owning a dazzler is the same thing. It just gets you another option ( non lethal ) if the other individual will not let you live it peace.

The ophiropt app isn't useful because it does not calculate power density at distance. Here's something more appropriate. https://www.laserworld.com/en/laserworld-toolbox/nohd-calculator.html

Even better. https://www.laserworld.com/en/laserworld-toolbox/szed-flashblindness-calculator.html

 

[BobMc]

The ophiropt app isn't useful because it does not calculate power density at distance. Here's something more appropriate. https://www.laserworld.com/en/laserworld-toolbox/nohd-calculator.html

Even better. https://www.laserworld.com/en/laserworld-toolbox/szed-flashblindness-calculator.html

Thanks for the heads up Steve, I haven't had the time to study the links yet but I appericate your help. The added links I'll save also. And study them when I get some free time. :thanks:

Edit; I trying your flashblindness calculator and it worked pretty good. Thanks.

 

[hakzaw1]

TY for the links.
I had started a thread somewhat on this topic in the Vets section.
if you care to read or post..

http://laserpointerforums.com/f61/r...ld-lasers-personal-protection-usa-100866.html

I expect to learn a lot when the video is made. no tracking # yet.

Encap-- well put +135

 

[steve001]

Thanks for the heads up Steve, I haven't had the time to study the links yet but I appericate your help. The added links I'll save also. And study them when I get some free time. :thanks:

Edit; I trying your flashblindness calculator and it worked pretty good. Thanks.

The first link from Laser Pointer Safety provided by Encap is just as useful as my "Even better" link.

 

[BobMc]

The first link from Laser Pointer Safety provided by Encap is just as useful as my "Even better" link.

Yes it is. I loaded the app on my phone. It will be easy to access. And a "hat tip" Encap.

 

[Encap]

Yes it is. I loaded the app on my phone. It will be easy to access. And a "hat tip" Encap.

THe Ophir Laser Power Density Calculator is a perfectly good tool for power distributed over an area given you know the laser power at the target. Really is just a calculation of W/cm squared for a circular area of whatever size you plug in.

NOHD and Flashblindness distances are very different. NOHD is a energy per cm squared calculation. NOHD does NOT depend on the wavelength-
Flashblindness distance is a human visual system phenomenon, a visual interference calculation that does depend on the wavelength.

NOHD is a calculation of W/cm squared laser power density same as the Ophir Laser Power Density calculator but also includes divergence. NOHD calculation takes into account how large the laser dot/spot will be at a given distance and what the beams power density is within the area of the dot/spot at a distance. It is a calculation of the distance where beam’s power density (irradiance) from the laser source drops below the Maximum Permissible Exposure limit of 2.54 milliwatts per square centimeter.
"NOHD is a standard laser safety concept. It expresses the “nominal” and not the actual distance at which a laser is deemed eye-safe. Keep in mind that the NOHD includes a safety factor of approximately 2/3. Example: for a 1 watt 1 milliradian visible laser with an NOHD of 733 feet, this means that under ideal conditions the laser has a 50% chance of causing a minimally detectable retinal lesion in the eye at 1/3 the NOHD distance, or 244 feet. The remaining 2/3 of the distance (489 feet) gives an additional safety factor. Obviously, the longer the distance from the laser, the lower the chance of eye injury. At 733 feet, there is essentially no chance of causing a retinal lesion in the eye"
See: Laser Pointer Safety - Basic principles of laser beam hazards for aviation

FAA SZED is generally taken to be flashblindness distance.
Flashblindness distance needs a Visual Correction Factor to be calculated because human visual system has different sensitivity to different wavelengths.
FAA. See: SZED equation and Selected FAA Visual Correction Factors chart used in SZED calculations here: Laser Pointer Safety - Laser hazard distance equations

Example of the difference--445nm blue laser -- "the NOHD and visual interference distances for a Spyder III Arctic laser. Using the actual output power of 800 mW and the manufacturer’s divergence of 1.5 milliradians for this laser, in calculations of NOHD and SZED the flashblindness distance of 384.9 feet is actually less than the eye hazard distance (NOHD) of 437.3 feet. This is because the human eye sees blue light poorly -- in this case, only 3% as well as the brightest green light."
This means as a real world practical matter that flashblinding with a 445nm blue laser can cause eye damage which is why 445nm blue lasers are not sold as "dazzlers" whereas 532nm green are.
Again from: Laser Pointer Safety - Laser hazard distance equations

There are sophisticated dazzlers that incorporate a laser rangefinder and if they detect if an observer is within the NOHD shut the laser off but they are expensive. The advantage is the person using the dazzler does not need to know anything about NOHD or flashblindness or calculations for same.
"The laser rapidly determines if an unintended observer is within the nominal ocular hazard distance (NOHD) and immediately shuts off the glaring output to prevent accidental eye injury. Once the bystander has moved out of the NOHD, the laser output instantly resumes" From: Maritime Security | GLARE LA-9/P | B.E. Meyers & Co., Inc.

It is interesting to note that the US Military dazzlers only have an output powers of 125mW, 200mW, and 250mW.
What we are talking about here are dazzlers that are many times that output power and therefore are more dangerous and both NOHD and SZED distance are far larger.
See mW output specs. in BE Meyers catalog here: http://bemeyers.com/wp-content/uploads/2013/04/BEMeyers-MicroCatalog-2014.pdf

PS While a little be obscure conceptually the real world calculations are all very simple mathematics, as follows:
NOHD (Nominal Ocular Hazard Distance) in feet = (32.8 ÷ milliradians) ✕ (square root of (0.5 ✕ milliwatts))

SZED (flashblindness distance) in feet = (32.8 ÷ milliradians) ✕ (square root of (12.7 ✕ milliwatts ✕ Visual Correction Factor for the wavelength you want an answer for))

 

[steve001]

THe Ophir Laser Power Density Calculator is a perfectly good tool for power distributed over an area given you know the laser power at the target. Really is just a calculation of W/cm squared for a circular area of whatever size you plug in.

NOHD and Flashblindness distances are very different. NOHD is a energy per cm squared calculation. NOHD does NOT depend on the wavelength-
Flashblindness distance is a human visual system phenomenon, a visual interference calculation that does depend on the wavelength.

NOHD is a calculation of W/cm squared laser power density same as the Ophir Laser Power Density calculator but also includes divergence. NOHD calculation takes into account how large the laser dot/spot will be at a given distance and what the beams power density is within the area of the dot/spot at a distance. It is a calculation of the distance where beam’s power density (irradiance) from the laser source drops below the Maximum Permissible Exposure limit of 2.54 milliwatts per square centimeter.
"NOHD is a standard laser safety concept. It expresses the “nominal” and not the actual distance at which a laser is deemed eye-safe. Keep in mind that the NOHD includes a safety factor of approximately 2/3. Example: for a 1 watt 1 milliradian visible laser with an NOHD of 733 feet, this means that under ideal conditions the laser has a 50% chance of causing a minimally detectable retinal lesion in the eye at 1/3 the NOHD distance, or 244 feet. The remaining 2/3 of the distance (489 feet) gives an additional safety factor. Obviously, the longer the distance from the laser, the lower the chance of eye injury. At 733 feet, there is essentially no chance of causing a retinal lesion in the eye"
See: Laser Pointer Safety - Basic principles of laser beam hazards for aviation

FAA SZED is generally taken to be flashblindness distance.
Flashblindness distance needs a Visual Correction Factor to be calculated because human visual system has different sensitivity to different wavelengths.
FAA. See: SZED equation and Selected FAA Visual Correction Factors chart used in SZED calculations here: Laser Pointer Safety - Laser hazard distance equations

Example of the difference--445nm blue laser -- "the NOHD and visual interference distances for a Spyder III Arctic laser. Using the actual output power of 800 mW and the manufacturer’s divergence of 1.5 milliradians for this laser, in calculations of NOHD and SZED the flashblindness distance of 384.9 feet is actually less than the eye hazard distance (NOHD) of 437.3 feet. This is because the human eye sees blue light poorly -- in this case, only 3% as well as the brightest green light."
This means as a real world practical matter that flashblinding with a 445nm blue laser can cause eye damage which is why 445nm blue lasers are not sold as "dazzlers" whereas 532nm green are.
Again from: Laser Pointer Safety - Laser hazard distance equations

There are sophisticated dazzlers that incorporate a laser rangefinder and if they detect if an observer is within the NOHD shut the laser off but they are expensive. The advantage is the person using the dazzler does not need to know anything about NOHD or flashblindness or calculations for same.
"The laser rapidly determines if an unintended observer is within the nominal ocular hazard distance (NOHD) and immediately shuts off the glaring output to prevent accidental eye injury. Once the bystander has moved out of the NOHD, the laser output instantly resumes" From: Maritime Security | GLARE LA-9/P | B.E. Meyers & Co., Inc.

It is interesting to note that the US Military dazzlers only have an output powers of 125mW, 200mW, and 250Mw.
What we are talking about here are dazzlers that are many times that output power and therefore are more dangerous and both NOHD and SZED distance are far larger.
See mW output specs. in BE Meyers catalog here: http://bemeyers.com/wp-content/uploads/2013/04/BEMeyers-MicroCatalog-2014.pdf

PS While a little be obscure conceptually the real wrold calculations are all very simple mathematics, as follows:
NOHD (Nominal Ocular Hazard Distance) in feet = (32.8 ÷ milliradians) ✕ (square root of (0.5 ✕ milliwatts))

SZED (flashblindness distance) in feet = (32.8 ÷ milliradians) ✕ (square root of (12.7 ✕ milliwatts ✕ Visual Correction Factor for the wavelength you want an answer for))

I looked at that calculator again. You are correct.

 

[BobMc]

@Encap & Steve; I appericate both your links. They seem like really good links to have at your finger tips. Thanks for posting them.

 

[Radim]

Bob, you might also create your own calculator. It is the best way how to learn how these things work. These calculations are not (completely) a rocket science and if you want accurate input for flash blindess and so, here is the data (even by 0.1 nm) I used for my own calculator:

Luminosity functions

It was mentioned above - check here - there are simplified equations: Laser Pointer Safety - Laser hazard distance equations

That is an interesting theory, but it causes prey animals to rely too heavily on sight alone. They are also able to hear better, sense vibrations in the ground and air along with their sense of smell, which you did admit to. There are many ways that prey animals have at their disposal to avoid predators. The young have little scent themselves for predators to pick up on and they blend in well with surrounding foliage to hide while their mothers can lead predators away from them.

Plants need more than just water and CO2 to develop all the proteins and other chemicals necessary for them to continue in this environment. N2, phosphor, trace minerals are all needed to make the chemicals plants use to survive. I think it was no accident that Papaver Somniferum, or the opium poppy makes the chemicals that mimic endogenous peptide endorphines that the body makes to suppress pain signals from getting to the brain. Many of the chemicals plants make are used by humans and this is an adaptive survival attempt by these plants to be used and cultivated in order to survive. Fruits have their seeds inside them so animals will eat and plant them with their feces. It's no wonder that many plants have genomes much larger than we have.

No, no, Paul, I did not think that the sight is the main or only sense. Definitely not. I was just talking about sight but not about other senses. In deed sight is often just "complementary" sense. For example if you consider dog smell sense, their sniffing aparatus is much more developed and even brain is focussed on that. That's why various smells carry a lot of information for them. Much more than for weak human smell sense.

I found this article to support this:
https://www.scienceabc.com/nature/animals/why-dogs-sense-of-smell-is-so-good.html

Or another example is bat, which can use echo location. Or sharks able to sniff a few molecules of substance in water or having sense of detect electromagnetic field:
https://en.wikipedia.org/wiki/Ampullae_of_Lorenzini

If I went deeper and discussed other senses - the article would be so long. Still I would like to mention also how robins (and likely other birds as well) use quantum mechanic based magnetic navigation sense - check here for example:
http://physicscentral.com/explore/action/pia-entanglement.cfm

And as I touched it already - I go back to smell - see here:
A quantum sense of smell - physicsworld.com

And regarding photosynthesis - I mentioned just the main elements involved - of course plants need much more as you mentioned - I should have mention "and other stuff" there. And also interesting thing from quantum mechanics:
https://phys.org/news/2014-01-quantum-mechanics-efficiency-photosynthesis.html


Regarding various substances plants produce, you are right. There are so many of them with various effects. Interesting example is that cannabinoids are exactly fitting receptors between neurons in human brain and of course basically everywhere in the body.
https://en.wikipedia.org/wiki/Cannabinoid_receptor
This is really huge potential of single plant which is extremely underestimated due to various really stupid reasons.

BTW going back again: And there are more examples where quantum mechanics is involved - that illustrates how complex the world is and how little we know about it or realize about it.

You see? There is even essence of my art and it will be explained more in coming article. Once it is finished.

Sorry for answering your post late, I was busy with work and festival - bad idea to combine. And sorry for a bit confusing structure. Still tired and getting ready for last festival day.

 

[BobMc]

Bob, you might also create your own calculator. It is the best way how to learn how these things work. These calculations are not (completely) a rocket science and if you want accurate input for flash blindess and so, here is the data (even by 0.1 nm) I used for my own calculator:

Luminosity functions

It was mentioned above - check here - there are simplified equations: Laser Pointer Safety - Laser hazard distance equations

Never thought of trying to make my own calculator Radim, might make one heck of a interesting project. Would also help with my understanding of the aspect of how light works. Thanks for the idea, I'll kick it around. :thanks:

 

[Encap]

Never thought of trying to make my own calculator Radim, might make one heck of a interesting project. Would also help with my understanding of the aspect of how light works. Thanks for the idea, I'll kick it around. :thanks:

Is all intereting and good to know.

The important bit is if you buy a Yamataka dazzler of whatever output power or wavelength, that you know the NOHD and flashblindnees distance for it, especially if you ever intend to use it as a dazzler---same goes for the JetLaser pistol dazzler.

You might want to check on California law with regard to use of a dazzler to be on the safe side legally.
Stun devices are legal to own an use in CA with a few exceptions. See details here: http://www.criminaldefenselawyer.com/resources/stungun-laws-california.htm

 

[BobMc]

Is all intereting and good to know.

The important bit is if you buy a 520nm Yamataka dazzler, that you know the NOHD and flashblindnees distance for it, especially if you ever intend to use it as a dazzler---same goes for the JetLaser pistol dazzler.

So very true Encap; those links you and Steve posted sure are informative. Thanks for posting them.

 

[Encap]

So very true Encap; those links you and Steve posted sure are informative. Thanks for posting them.

PS here is 2017 Laserpointersafety link that discusses a new laser safety concept, the Nominal Ocular Dazzle Distance (NODD) concept and how to calculate it.

“The MDE is the threshold laser irradiance at the eye below which a given target can be detected. It can also be used as a measure of the minimum laser irradiance required to obscure a given target.”

“The NODD is the minimum distance for the visual detection of a target in the presence of laser dazzle. It also represents the maximum effective range of a laser dazzle system designed to prevent the visual detection of a target.”

See: Laser Pointer Safety - The Nominal Ocular Dazzle Distance concept