4 ms·

I have worked with watt class lasers before and I implore you not to do this. Even if it's tempting. Most places where there are surveillance cameras are places

by 0_____0 8mo ago

I have worked with watt class lasers before and I implore you not to do this. Even if it's tempting. Most places where there are surveillance cameras are places where there are also people, and unless you want to hand out OD5 goggles to everyone in eyeshot... a pellet gun would be safer.

Terr_ 8mo ago
> Most places where there are surveillance cameras are places where there are also people I assume you're concerned about reflections from the camera lens or housing? In my mind, the archetypal camera is mounted on a nice tall pole, silhouetted against open sky, and painted matte black. > watt class lasers Surely those would be excessive for someone attacking the sensor, unless they want to remotely sear some graffiti by burning away paint.
- hinkley 8mo ago
  Hitting the lens at an oblique angle won’t fry the sensor though? You have to get close to the cone of visibility which is then within the bloom area.
hinkley 8mo ago
My friend in college did an internship on high frequency, short pulse beams (I wanna say violet and picosecond? Which I still think was exotic at the time). Most of his work was dealing with and accounting for reflections that left the machine. If you have a prism that’s sending 95% of the light where you want it to go, when it’s a multi watt laser you can’t just let that 5% go wherever it wants. You will blind someone. So his job was getting black bodies in all the right spots to absorb the lost light. His safety goggles looked like even more expensive Oakleys of that era and they were (much more expensive).
- cyberax 8mo ago
  The amount of safety when working with lasers is ridiculous. And for a good reason, you can get permanent eye damage faster than the blink of an eye. Please, don't play with lasers. At all. Even supposedly "safe" lasers can output far more light than expected.
  - hinkley 8mo ago
    Another friend’s favorite saying is, “do not look into laser with remaining eye.”
  - flowerthoughts 8mo ago
    Not to mention the ones that have peaks in invisible parts of the spectrum.
palata 8mo ago
Unrelated, but I really want to take the opportunity: How can one know what is dangerous for the eyes or not? Years ago I got an "IR illuminator" (from aliexpress, probably) that I wanted to use with my raspberrypi NoIR camera, for fun. Say filming myself during the night to see how much I move while sleeping, or making my own wildlife camera trap. But I was scared that it could be dangerous and never used it (I tested it in an empty room, but that was it). Is there a safe way for a hobbyist to get an IR illuminator and be sure that I won't make somebody blind with it?
- elictronic 8mo ago
  Buy from a reputable dealer. I don’t buy batteries, lasers, or items I ingest from locations lacking any repercussions.
- duskwuff 8mo ago
  IR illuminators are not lasers. Their purpose is to cast light across a broad area, not to deliver it all to one point. They should not be harmful to vision.
- 0_____0 8mo ago
  Is it just a bunch of IR LEDs? Surface mount or through-hole? What's the module power rating? What's the power supply power rating? Are there any secondary optics like lenses over the LEDs? Is there a diffuser of some kind? If it's a cluster of garden variety through-hole LEDs with domed tops (like you would see on a TV remote), they're necessarily low power on account of having poor thermal performance. Another way to tell is if nothing gets warm at all. It's pretty hard to hurt someone with an emitter that both doesn't have a focusing optic and doesn't get warm. Let me be clear - you're still responsible for verifying the safety of your stuff, and I am in no way assuring you that the device you have is benign, because I can't do that without inspecting it directly.
  - palata 8mo ago
    Yeah, let's say something like this: https://www.instructables.com/DIY-IR-Infrared-Illuminator-Night-Viewing-With/ https://www.instructables.com/DIY-IR-Infrared-Illuminator-Ni... > Let me be clear - you're still responsible for verifying the safety of your stuff Obviously yeah. I was just wondering if there were known rules like "these wavelengths under this power are fine for humans and wildlife, even if they put the LEDs right in front of their eyes", and also if you have an array of such IR LEDs, how they cumulate. And curious about things like: if I don't see it, can it hurt my retina? I probably will never do it: I wouldn't want to blind a fox just because I wanted to make my own wildlife camera :).

by 0_____0 8mo ago

Terr_ 8mo ago

> Most places where there are surveillance cameras are places where there are also people I assume you're concerned about reflections from the camera lens or housing? In my mind, the archetypal camera is mounted on a nice tall pole, silhouetted against open sky, and painted matte black. > watt class lasers Surely those would be excessive for someone attacking the sensor, unless they want to remotely sear some graffiti by burning away paint.

hinkley 8mo ago
Hitting the lens at an oblique angle won’t fry the sensor though? You have to get close to the cone of visibility which is then within the bloom area.

hinkley 8mo ago

My friend in college did an internship on high frequency, short pulse beams (I wanna say violet and picosecond? Which I still think was exotic at the time). Most of his work was dealing with and accounting for reflections that left the machine. If you have a prism that’s sending 95% of the light where you want it to go, when it’s a multi watt laser you can’t just let that 5% go wherever it wants. You will blind someone. So his job was getting black bodies in all the right spots to absorb the lost light. His safety goggles looked like even more expensive Oakleys of that era and they were (much more expensive).

cyberax 8mo ago
The amount of safety when working with lasers is ridiculous. And for a good reason, you can get permanent eye damage faster than the blink of an eye. Please, don't play with lasers. At all. Even supposedly "safe" lasers can output far more light than expected.
- hinkley 8mo ago
  Another friend’s favorite saying is, “do not look into laser with remaining eye.”
- flowerthoughts 8mo ago
  Not to mention the ones that have peaks in invisible parts of the spectrum.

palata 8mo ago

Unrelated, but I really want to take the opportunity: How can one know what is dangerous for the eyes or not? Years ago I got an "IR illuminator" (from aliexpress, probably) that I wanted to use with my raspberrypi NoIR camera, for fun. Say filming myself during the night to see how much I move while sleeping, or making my own wildlife camera trap. But I was scared that it could be dangerous and never used it (I tested it in an empty room, but that was it). Is there a safe way for a hobbyist to get an IR illuminator and be sure that I won't make somebody blind with it?

elictronic 8mo ago
Buy from a reputable dealer. I don’t buy batteries, lasers, or items I ingest from locations lacking any repercussions.
duskwuff 8mo ago
IR illuminators are not lasers. Their purpose is to cast light across a broad area, not to deliver it all to one point. They should not be harmful to vision.
0_____0 8mo ago
Is it just a bunch of IR LEDs? Surface mount or through-hole? What's the module power rating? What's the power supply power rating? Are there any secondary optics like lenses over the LEDs? Is there a diffuser of some kind? If it's a cluster of garden variety through-hole LEDs with domed tops (like you would see on a TV remote), they're necessarily low power on account of having poor thermal performance. Another way to tell is if nothing gets warm at all. It's pretty hard to hurt someone with an emitter that both doesn't have a focusing optic and doesn't get warm. Let me be clear - you're still responsible for verifying the safety of your stuff, and I am in no way assuring you that the device you have is benign, because I can't do that without inspecting it directly.
- palata 8mo ago
  Yeah, let's say something like this: https://www.instructables.com/DIY-IR-Infrared-Illuminator-Night-Viewing-With/ https://www.instructables.com/DIY-IR-Infrared-Illuminator-Ni... > Let me be clear - you're still responsible for verifying the safety of your stuff Obviously yeah. I was just wondering if there were known rules like "these wavelengths under this power are fine for humans and wildlife, even if they put the LEDs right in front of their eyes", and also if you have an array of such IR LEDs, how they cumulate. And curious about things like: if I don't see it, can it hurt my retina? I probably will never do it: I wouldn't want to blind a fox just because I wanted to make my own wildlife camera :).