So I was researching stuff about smoke sensors and I may be paranoid but I was wondering if they were Safe for kids and in general , I read they had infrared LEDS which I heard were very harmful for eyes if looked at directly which I assume the IR LESS are inside and nor visible outside the smoke detector but I was wondering if there was any way the LED can leak out and harm a child since they are curious and like to stare at lights/ etc.. Just got me thinking thanks for the feedback
The LED in a smoke detector is safe to look at. Not only that, but the smoke detector is constructed in such a way that the light of this LED does not actually escape the device. It is hidden away in such a way that light can't get in from the outside, as this may disturb the sensor's ability to detect the smoke. This structure works both ways, and hence the light can also not get out.
In other words, they are completely safe and your children will be far safer with a smoke detector around.
Infrared LEDs are perfectly safe to look at. They're what are used in most remote controls, for instance, as well as on many "night vision" surveillance cameras. Some very bright infrared LEDs can be seen as very dim red light, but even these are not harmful -- and the LEDs in a smoke detector will be much smaller than that.
In principle, IR radiation can damage your eyes. However, that doesn't mean that the IR LED within a smoke detector (which has special form as to not let out much of the radiation at all, plus it is inside a plastic case) isn't perfectly safe. It is, by all means, perfectly safe.
The "night-vision" light used in every surveillance camera or webcam with support for enhanced "dark vision" comes from a IR LED and has, depending on model, anywhere from 500 to 2,500 times the power of the LED in a smoke detector. IR flood lights such as the one I'm using to have my garden appear bright as in daylight on the surveillance camera have more like 500,000-1,000,000 times as much.
None of these damage your eyes (though the latter does irritate night-active insects as they can see the light, alas it also irritates burglars, which is more important to me).
IR light used to be, once upon a time when safety at work was written in small caps, a known source of eye disorders with metal workers. But here, we're talking about, I don't know, 100 billion times the radiation intensity of my garden flood light, and exposure over years.
That's nowhere near comparable to the intensity of what's inside a well-sealed smoke detector.