Many questions!

Hallucynogenyc said:

(put the "WWW." missing in front of the links, it says I cannot post them b4 10 posts -.-)


Hi! I'm actually an ignorant in the amazing laser pointers world, so I've decided to investigate a bit

I bought a 80mW from an ebay seller called Subtel2008 for 20€ (25$). He have the lowest prices in the net i could find, so or my first laser it was Ok.

I'm sure its not real 80mW green light, not even 80mW at all) a week ago and after being testing around I've found out some interesting things. I'm ataching a winrar file with some photos of the laser and the effects I talk about now (feel free to chek with antivirus if u want )

Just after reciving it the first thing i got impressed by was the so damn fast speed the batteries were wasting. I bought a 1000maH nimh cells but (I know now its because of the difference of power beetween the alkalines 1.5-1.2) they didnt worked.

So the first thing i ask is:

Would 3 rechargeable batteries burn out the laser? And if it is, is there any alternative to wasting 2 AAA high quality cells every hour? I think not at first, because alkalines usually come at 1.6, so the laser must be prepared to face a 3.2V power, its just a 10.5% overpowered, wich I would expect to be in the tolerance range, but those ebay lasers...

I don't know this one. Someone might have tried it with a similar laser here, but in general, stick to manufacturer specifications unless you're willing to risk losing your laser. But if you're willing to risk it and don't care about the money, then you can try it. It's your laser and money, afterall.

I also thought about putting a resistor between the laser and the cells, but the amperimeter in my multimeter is fused, and so i can't calculate what resistor do I need. I tested with the lowest i found at home (56ohm) and the power went from 3.6 to 2.0, I will try to buy a lower one.

It's not that the laser is not working with 1 hour usetime, but under 1.4 the brightness starts going down so fast so i need to change them.

The second question is:

How can I test the power of the laser beam, and how can I test the laser power at all? (without potentiometer)

Short answer: the only way to test the exact power if with a laser power meter. But really, you bought a cheap laser that was advertised as 80mW, but it sounds like it's brighter than 5mW, so I'd venture it's somewhere between those two numbers. 30-50 is not an unreasonable guess, and unless you want to drop some cash on a power meter, then there's no way to know for sure.

For the first part, looking at the photos could help you, as far as i can tell you, It can pop a black balloon from like 1 meter~, i't cant no way light a match, and It only cuts black tape if I tense it a lot, in normal conditions it don't even make a little hole.

For the second part, I actually dispose of a large ammount of resistors, a voltimeter, and a resistometer, gimme ideas! I tried to put the resistometer to the laser directly to apply then P=V·I, put it doesnt work at all, it shows too high values, I suspect theres some kind of variable resistor inside, VDR maybe. testing it while its connected leads to a even higher value.

I tested with resistors and testing their resistence while they are working makes the multimeter confusing too, maybe you can tell me whats the relation of the real value and the value you get this way?

Not quite sure what you're saying here. The laser will be drawing several hundred mA of current at <2V for the diode, but without knowing what the driver is or more info in general, I don't know exactly how much power it is drawing. Put a current meter in series to get the current, measure the voltage across the batteries while in operation, and that's how much power it's drawing from the batteries.

The third thing i Thoguht about was of the IR light. I have studied some light phisycs on school so I thoght that making it diffract would separate it.

tufts.edu/as/tampl/projects/micro_rs/diffraction.jpg

Seeing the IR light is kinda easy, almost all cameras show it, even the mobile ones (not the expensive cameras, those got a filter). Easy way tot test if ur camera can do that is to look at a remote control while pressing keys on it.

It didnt worked for me ( tested with water), because the green light make the screen so bright and u cant see whats next to the dot.

So the fact was to filter the green light somehow so I could see if there was IR. The solution came randomly when i saw the SpyKids 3 3D movie glasses. The red part of them is filtering like the 95% of the green light. I think any red and transparent plastic does that. (I made a protection glasses with another part from the other glasses, there are like 4 of them on the movie box)

And this time i could see the IR perfectly. Eve with my Sonyericson mobile camera its clearly visible a white-grey light.

And so here it comes the 4th question:

Is there any way to filter the IR light for free or for a so cheap price? (remember the laser was 20€, im not gona pay 10 for a fucking filter ).

Yeah, just IR filters on the internet. That's pretty much just the way to block IR effectively, is using a filter that will absorb the IR and transmit the green. Sorry.

I saw a guy post somewhere saying there are IR filters on webcams, but i couldn't find none on my crappy webcam. Anywhere else to find it?

By the way I was testing with mirrors, i saw in one of the mirrors at home the laser beam was becoming red inside the mirror (more details on photos). I've been thinking about the refraction, but air is suppsed to have the lower refraction index, and so going into the mirror would reduce the wave longitude. And here i thought "lol its the IR light getting refracted). But not! i tested the same filtering the green light (wich leaves the IR) and it doesnt happen anymore.

So, the 5th is:

How is it possible the light is getting accelerated when going to a more dense environment!?


The light isn't getting accelerated, you have it backwards and you're slightly mixing some different ideas. refractive index is the speed of light int he medium, and the index is higher for solids vs. air, which means the light is traveling slower inside the solid. But that has nothing to do with seeing different colors. The refractive index changes the speed, but not the wavelength of the light. When you see a different color, you are seeing fluorescence. You can google it to read more about it, but basically electrons in the glass or on other surfaces absorb the green light, and re-emit a different color of light that depends only on the atom/electron that absorbed the green light. The emitted light will be a longer wavelength/lower energy/lower frequency because of the electron structure, and (almost) never a shorter wavelength/higher energy. Green light can cause yellow, orange, or red light to be emitted, but not blue or purple.

While getting bored I accidentaly pointed to a red surface and the dot became yellow. After testing, I've seen it happens on some surfaces. Why?

Fluorescence again.

And finally the last one  

I've accidentaly been slef-pointed throught a mirror once and at like 5 cm from the laser directly on my eye (dont ask me how could that hapened I was just so idiot enough to try to see what was making the laser light at all and i puted my eye cleser and closer to the beam until... oh my fucking god I'm damn idiot xd)

What conequences can I expect from that, what could happen if it happens again and when are them coming at what are the symptoms of getting pointed?

Hitting you eye with a >5mW green laser will cause permanent retinal burns, basically deal pixels in your eye. Typically, people might notice the little dead spots at first, but your brain will adjust for these overtime and you won't generally see them as much. But the damage is permanent. AND if you're unlucky and that one little spot that gets burned by the beam happens to be on your optic nerve, then it can actually completely blind you. Basically, nothing good can coem of it, so be more careful and don't hit yourself in the eye with a laser. If you're going to be using powerful laser pointers regularly (powerful being >5mW, generally), then you NEED safety goggle sot protect your eyes from the laser light.

Sorry for my English, I'm a 17 years old Spanish guy, what could you expect...  ;D

Thanks for your time,
Hallucynogenyc



LINK FOR PHOTOS AND SO:
speedyshare.com/882374943.html

Click to expand...

(put the "WWW." missing in front of the links, it says I cannot post them b4 10 posts -.-)


Hi! I'm actually an ignorant in the amazing laser pointers world, so I've decided to investigate a bit

I bought a 80mW from an ebay seller called Subtel2008 for 20[ch8364] (25$). He have the lowest prices in the net i could find, so or my first laser it was Ok.

I'm sure its not real 80mW green light, not even 80mW at all) a week ago and after being testing around I've found out some interesting things. I'm ataching a winrar file with some photos of the laser and the effects I talk about now (feel free to chek with antivirus if u want )

Just after reciving it the first thing i got impressed by was the so damn fast speed the batteries were wasting. I bought a 1000maH nimh cells but (I know now its because of the difference of power beetween the alkalines 1.5-1.2) they didnt worked.

So the first thing i ask is:

Would 3 rechargeable batteries burn out the laser? And if it is, is there any alternative to wasting 2 AAA high quality cells every hour? I think not at first, because alkalines usually come at 1.6, so the laser must be prepared to face a 3.2V power, its just a 10.5% overpowered, wich I would expect to be in the tolerance range, but those ebay lasers...

I don't know this one. Someone might have tried it with a similar laser here, but in general, stick to manufacturer specifications unless you're willing to risk losing your laser. But if you're willing to risk it and don't care about the money, then you can try it. It's your laser and money, afterall. ok

I also thought about putting a resistor between the laser and the cells, but the amperimeter in my multimeter is fused, and so i can't calculate what resistor do I need. I tested with the lowest i found at home (56ohm) and the power went from 3.6 to 2.0, I will try to buy a lower one. good idea or not?

It's not that the laser is not working with 1 hour usetime, but under 1.4 the brightness starts going down so fast so i need to change them.

The second question is:

How can I test the power of the laser beam, and how can I test the laser power at all? (without potentiometer)

Short answer: the only way to test the exact power if with a laser power meter. But really, you bought a cheap laser that was advertised as 80mW, but it sounds like it's brighter than 5mW, so I'd venture it's somewhere between those two numbers. 30-50 is not an unreasonable guess, and unless you want to drop some cash on a power meter, then there's no way to know for sure. What I meant was taht u tell me whats the power you bet it have looking at the photos and the features i said

For the first part, looking at the photos could help you, as far as i can tell you, It can pop a black balloon from like 1 meter~, i't cant no way light a match, and It only cuts black tape if I tense it a lot, in normal conditions it don't even make a little hole.

For the second part, I actually dispose of a large ammount of resistors, a voltimeter, and a resistometer, gimme ideas! I tried to put the resistometer to the laser directly to apply then P=V·I, put it doesnt work at all, it shows too high values, I suspect theres some kind of variable resistor inside, VDR maybe. testing it while its connected leads to a even higher value.

I tested with resistors and testing their resistence while they are working makes the multimeter confusing too, maybe you can tell me whats the relation of the real value and the value you get this way?

Not quite sure what you're saying here. The laser will be drawing several hundred mA of current at <2V for the diode, but without knowing what the driver is or more info in general, I don't know exactly how much power it is drawing. Put a current meter in series to get the current, measure the voltage across the batteries while in operation, and that's how much power it's drawing from the batteries. I mean, maybe the seller tried to scam the easy waqy to add a resistor inside so the laser is taking more power if u try to test with a powermeter or if he just changed the label. I said I did not have a current meter just a voltimeter

The third thing i Thoguht about was of the IR light. I have studied some light phisycs on school so I thoght that making it diffract would separate it.

tufts.edu/as/tampl/projects/micro_rs/diffraction.jpg

Seeing the IR light is kinda easy, almost all cameras show it, even the mobile ones (not the expensive cameras, those got a filter). Easy way tot test if ur camera can do that is to look at a remote control while pressing keys on it.

It didnt worked for me ( tested with water), because the green light make the screen so bright and u cant see whats next to the dot.

So the fact was to filter the green light somehow so I could see if there was IR. The solution came randomly when i saw the SpyKids 3 3D movie glasses. The red part of them is filtering like the 95% of the green light. I think any red and transparent plastic does that. (I made a protection glasses with another part from the other glasses, there are like 4 of them on the movie box)

And this time i could see the IR perfectly. Eve with my Sonyericson mobile camera its clearly visible a white-grey light.

And so here it comes the 4th question:

Is there any way to filter the IR light for free or for a so cheap price? (remember the laser was 20[ch8364], im not gona pay 10 for a fucking filter ).

Yeah, just IR filters on the internet. That's pretty much just the way to block IR effectively, is using a filter that will absorb the IR and transmit the green. Sorry. isnt there a chepaer one evenm if u dont filter all the IR?

I saw a guy post somewhere saying there are IR filters on webcams, but i couldn't find none on my crappy webcam. Anywhere else to find it?

By the way I was testing with mirrors, i saw in one of the mirrors at home the laser beam was becoming red inside the mirror (more details on photos). I've been thinking about the refraction, but air is suppsed to have the lower refraction index, and so going into the mirror would reduce the wave longitude. And here i thought "lol its the IR light getting refracted). But not! i tested the same filtering the green light (wich leaves the IR) and it doesnt happen anymore.

So, the 5th is:

How is it possible the light is getting accelerated when going to a more dense environment!?


The light isn't getting accelerated, you have it backwards and you're slightly mixing some different ideas. refractive index is the speed of light int he medium, and the index is higher for solids vs. air, which means the light is traveling slower inside the solid. But that has nothing to do with seeing different colors. The refractive index changes the speed, but not the wavelength of the light. When you see a different color, you are seeing fluorescence. You can google it to read more about it, but basically electrons in the glass or on other surfaces absorb the green light, and re-emit a different color of light that depends only on the atom/electron that absorbed the green light. The emitted light will be a longer wavelength/lower energy/lower frequency because of the electron structure, and (almost) never a shorter wavelength/higher energy. Green light can cause yellow, orange, or red light to be emitted, but not blue or purple.

In fact my physic book says the oposite. It says that refraction changes the angle of the beam due to the change of speed. And the speed change is due to te wavelenght change because the frequency isnt changing (speed =wavelenght · frequency). I asked to my teacher if the wavelenght was really changing and he said yes, and when i said him that was imposible cuz light doesnt change his color inside water he said me that was cuz water wasnt chaning it enough (wich is also stupid cuz itz 1.33 wich would alredy chagne e color) If its fluorescence, then what's changing the speed? Also notice how white light gets refracted in all the other colors in a prism exactly cuz of that i said. (diferent wavelenght change = different angle. (Look the link some lines above)

While getting bored I accidentaly pointed to a red surface and the dot became yellow. After testing, I've seen it happens on some surfaces. Why?

Fluorescence again.

And finally the last one

I've accidentaly been slef-pointed throught a mirror once and at like 5 cm from the laser directly on my eye (dont ask me how could that hapened I was just so idiot enough to try to see what was making the laser light at all and i puted my eye cleser and closer to the beam until... oh my fucking god I'm damn idiot xd)

What conequences can I expect from that, what could happen if it happens again and when are them coming at what are the symptoms of getting pointed?

Hitting you eye with a >5mW green laser will cause permanent retinal burns, basically deal pixels in your eye. Typically, people might notice the little dead spots at first, but your brain will adjust for these overtime and you won't generally see them as much. But the damage is permanent. AND if you're unlucky and that one little spot that gets burned by the beam happens to be on your optic nerve, then it can actually completely blind you. Basically, nothing good can coem of it, so be more careful and don't hit yourself in the eye with a laser. If you're going to be using powerful laser pointers regularly (powerful being >5mW, generally), then you NEED safety goggle sot protect your eyes from the laser light. If i home made ones wich are filtering almost all the green light is it ok? I'll post a photo of them filtering soo u can see.

Sorry for my English, I'm a 17 years old Spanish guy, what could you expect...

Thanks for your time,
Hallucynogenyc



LINK FOR PHOTOS AND SO:
speedyshare.com/882374943.html

Click to expand...

Hallucynogenyc said:

The second question is:

How can I test the power of the laser beam, and how can I test the laser power at all? (without potentiometer)

Short answer: the only way to test the exact power if with a laser power meter. But really, you bought a cheap laser that was advertised as 80mW, but it sounds like it's brighter than 5mW, so I'd venture it's somewhere between those two numbers. 30-50 is not an unreasonable guess, and unless you want to drop some cash on a power meter, then there's no way to know for sure.

What I meant was taht u tell me whats the power you bet it have looking at the photos and the features i said

I understand what you were saying, but there's no way anyone on here can tell how powerful your laser is by looking at pictures, really. Maybe someone else can give you a better idea based on if it can or can't light matches/can or can't pop balloons. But those things also depend hugely on how well focused the laser it. A well-focuesed beam needs much less power to do those things, so that will change the guesstimate of power. Like I said, 30-50mW is a reasonable guess.

For the first part, looking at the photos could help you, as far as i can tell you, It can pop a black balloon from like 1 meter~, i't cant no way light a match, and It only cuts black tape if I tense it a lot, in normal conditions it don't even make a little hole.

For the second part, I actually dispose of a large ammount of resistors, a voltimeter, and a resistometer, gimme ideas! I tried to put the resistometer to the laser directly to apply then P=V·I, put it doesnt work at all, it shows too high values, I suspect theres some kind of variable resistor inside, VDR maybe. testing it while its connected leads to a even higher value.

I tested with resistors and testing their resistence while they are working makes the multimeter confusing too, maybe you can tell me whats the relation of the real value and the value you get this way?

Not quite sure what you're saying here. The laser will be drawing several hundred mA of current at <2V for the diode, but without knowing what the driver is or more info in general, I don't know exactly how much power it is drawing. Put a current meter in series to get the current, measure the voltage across the batteries while in operation, and that's how much power it's drawing from the batteries.

I mean, maybe the seller tried to scam the easy waqy to add a resistor inside so the laser is taking more power if u try to test with a powermeter or if he just changed the label. I said I did not have a current meter just a voltimeter

Yeah, I still don't understand what you're saying here. I don't know what kind of driver or what components are in your laser, so I don't know if it was modified or what. Most likely, it was a cheap chinese-made laser that was advertised at 80mW and sold thta way, but likely isn't putting out quite that much. If you want to know what's inside, you'll have to take it apart. But if you're wondering how good the quality is, it's likely not as good as name brands, but if it works, that's all that matters. If you're happy with your laser, then it wasn't a scam, simple as that.

The third thing i Thoguht about was of the IR light. I have studied some light phisycs on school so I thoght that making it diffract would separate it.

tufts.edu/as/tampl/projects/micro_rs/diffraction.jpg

Seeing the IR light is kinda easy, almost all cameras show it, even the mobile ones (not the expensive cameras, those got a filter). Easy way tot test if ur camera can do that is to look at a remote control while pressing keys on it.

It didnt worked for me ( tested with water), because the green light make the screen so bright and u cant see whats next to the dot.

So the fact was to filter the green light somehow so I could see if there was IR. The solution came randomly when i saw the SpyKids 3 3D movie glasses. The red part of them is filtering like the 95% of the green light. I think any red and transparent plastic does that. (I made a protection glasses with another part from the other glasses, there are like 4 of them on the movie box)

And this time i could see the IR perfectly. Eve with my Sonyericson mobile camera its clearly visible a white-grey light.

And so here it comes the 4th question:

Is there any way to filter the IR light for free or for a so cheap price? (remember the laser was 20€, im not gona pay 10 for a fucking filter ).

Yeah, just IR filters on the internet. That's pretty much just the way to block IR effectively, is using a filter that will absorb the IR and transmit the green. Sorry.

isnt there a chepaer one evenm if u dont filter all the IR?

Googling "IR filter" or other related terms, or posting an "I want to buy an IR filter" thread in the Buy/Sell/Trade forum here is about the best you can do.

I saw a guy post somewhere saying there are IR filters on webcams, but i couldn't find none on my crappy webcam. Anywhere else to find it?

By the way I was testing with mirrors, i saw in one of the mirrors at home the laser beam was becoming red inside the mirror (more details on photos). I've been thinking about the refraction, but air is suppsed to have the lower refraction index, and so going into the mirror would reduce the wave longitude. And here i thought "lol its the IR light getting refracted). But not! i tested the same filtering the green light (wich leaves the IR) and it doesnt happen anymore.

So, the 5th is:

How is it possible the light is getting accelerated when going to a more dense environment!?  

The light isn't getting accelerated, you have it backwards and you're slightly mixing some different ideas. refractive index is the speed of light int he medium, and the index is higher for solids vs. air, which means the light is traveling slower inside the solid. But that has nothing to do with seeing different colors. The refractive index changes the speed, but not the wavelength of the light. When you see a different color, you are seeing fluorescence. You can google it to read more about it, but basically electrons in the glass or on other surfaces absorb the green light, and re-emit a different color of light that depends only on the atom/electron that absorbed the green light. The emitted light will be a longer wavelength/lower energy/lower frequency because of the electron structure, and (almost) never a shorter wavelength/higher energy. Green light can cause yellow, orange, or red light to be emitted, but not blue or purple.

In fact my physic book says the oposite. It says that refraction changes the angle of the beam due to the change of speed. And the speed change is due to te wavelenght change because the frequency isnt changing (speed =wavelenght · frequency). I asked to my teacher if the wavelenght was really changing and he said yes, and when i said him that was imposible cuz light doesnt change his color inside water he said me that was cuz water wasnt chaning it enough (wich is also stupid cuz itz 1.33 wich would alredy chagne e color) If its fluorescence, then what's changing the speed? Also notice how white light gets refracted in all the other colors in a prism exactly cuz of that i said. (diferent wavelenght change = different angle. (Look the link some lines above)

I did write one thing incorrectly, I wasn't thinking clearly, and I marked that part out. Yes, the wavelength changes as the speed changes, the freguency doesn't change. So the wavelength is different ONLY while the light is inside the glass, but your eye isn't inside the glass, is it? Once the light comes back out of the glass, the wavelength will be back to 532nm, green, again. Yes, the wavelength of light is different inside the glass, but you'll never see that yourself, because the light has to come back out of the glass before your eye can see it. Since the wavelength changes depending on medium, the medium your eye is in is the ONLY medium your eye will ever see, and that's air. Green light goes into the glass, it's a different wavelength while it's in there, but once it comes back out, it's green again, see what I mean? The only way you ever see a different color of light is if a different color of light is EMITTED by the glass, and that's where the fluorescence comes into play. The glass emits red light when hit with green. That light is also a different wavelength while inside the glass, but in air it is a wavelength that corresponds to red. And really, and it's even so much about the wavelength in air as it is about the wavelength inside your eye. The refractive index inside your eye won't change and is different from the refractive index of air, so the wavelength of light while inside your eye is really what color you're seeing. Since the frequency never changes, that's really what's deciding what color you see. See what I mean?

And that's very astute pointing out that light that has passed through water is still the same color, it works the same with glass. Glass is n=~1.5, you say water is about 1.3, really very little difference. So you see, it's fluorescence that makes you SEE a different color, you'll never see a changed wavelength inside a material because the index of refraction changes again once the light leaves the material and goes to your eye.

And a prism isn't changing the wavelength of the light that comes out, it is DIVIDING the light that comes out. White has all the other colors in it, a prism simply divides them up into separate beams.

What conequences can I expect from that, what could happen if it happens again and when are them coming at what are the symptoms of getting pointed?

Hitting you eye with a >5mW green laser will cause permanent retinal burns, basically deal pixels in your eye. Typically, people might notice the little dead spots at first, but your brain will adjust for these overtime and you won't generally see them as much. But the damage is permanent. AND if you're unlucky and that one little spot that gets burned by the beam happens to be on your optic nerve, then it can actually completely blind you. Basically, nothing good can coem of it, so be more careful and don't hit yourself in the eye with a laser. If you're going to be using powerful laser pointers regularly (powerful being >5mW, generally), then you NEED safety goggle sot protect your eyes from the laser light.

If i home made ones wich are filtering almost all the green light is it ok? I'll post a photo of them filtering soo u can see.

Laser goggles are special because they can stand up to the laser light. When light hits the dyes that block certain colors, the dyes actually start to break down. Home-made goggles won't stand up to laser light. They will bleach and begin allowing more light into your eye than should be allowed. The only goggles than be completely trusted are those that have been tested and certified to defined standards and manufactured by trusted companies. Go read up in the Safety section for more on this.

Click to expand...

Hallucynogenyc said:

I'm sure its not real 80mW green light, not even 80mW at all) a week ago and after being testing around I've found out some interesting things. I'm ataching a winrar file with some photos of the laser and the effects I talk about now (feel free to chek with antivirus if u want )

The second question is:

How can I test the power of the laser beam, and how can I test the laser power at all? (without potentiometer)


Thanks for your time,
Hallucynogenyc


LINK FOR PHOTOS AND SO:
speedyshare.com/882374943.html

Click to expand...

Hallucynogenyc said:

but u guys have seen hundreds of laser images, I'm sure you can tell me whats the aproximate power by looking at the photos! and considering it cant light a match and barely cut black type. It only pop balloons from like 1 meter or so

@pullbangdead: oh lol the air inside my eye ffs I didnt thought on it haha Thanks, nice to see you guys know more about it than my teacher, who just told me "shut up with stupid questions and make the exercises I ordered" xd

@laserbee@the first one is amazing but, 40$, i wasted 25 on laser! xd the second one 300$ lol I buy a 300$ laser better and i know the power for sure xd

Click to expand...

Hallucynogenyc said:

@laser bee: omg that was the most helpful post i ever saw -.-'

I'm usre u can distinguish between a 30 and a 80mW just looking at it.Or you can't?

Click to expand...

Hallucynogenyc said:

@laser bee: omg that was the most helpful post i ever saw -.-'

I'm usre u can distinguish between a 30 and a 80mW just looking at it.Or you can't?

Click to expand...

pullbangdead said:

Here's an example to demonstrate this.  Here are 2 photos, one is 5mW and one is 100mW.  Can you even tell which is which?

Click to expand...

691175002 said:

Id like to point out that your eye isn't filled with air, it is filled with vitreous humor.

Click to expand...