Naked Science Forum

General Science => General Science => Topic started by: paul.fr on 19/10/2007 10:54:20

Title: how could i make home made night vision glasses?
Post by: paul.fr on 19/10/2007 10:54:20

Could i make them easily at home? Could i convert a pair of binoculars?

Title: how could i make home made night vision glasses?
Post by: another_someone on 19/10/2007 14:02:01

Night vision glasses are electronic devices rather than optical - you need to obtain the appropriate electronic to do it.

Title: how could i make home made night vision glasses?
Post by: neilep on 19/10/2007 14:31:30

All you need do is attach a big old torch to the top of your head !!

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Title: how could i make home made night vision glasses?
Post by: lyner on 19/10/2007 16:40:33

They are available - I have seen them- for not many tens of pounds.
The cheapo ones are probably a bit poor - but enough the see wild mammals in the garden at night - or robbers!
This guy claims to have made one!
http://www.angelfire.com/80s/sixmhz/infrared.html (http://www.angelfire.com/80s/sixmhz/infrared.html)
There are lots of webcams which claim to do it - really cheap.

Title: how could i make home made night vision glasses?
Post by: eric l on 19/10/2007 16:46:04

I remember reading something about an "image intensifier" based un bundling glass fibres and not needing electronic amplifying.  But I never saw one in action, and I don't recall reading about it again - and that must be for something like 10 years.  Maybe it was just a hoax.

Title: how could i make home made night vision glasses?
Post by: RD on 19/10/2007 18:00:35

Ordinary video cameras can "see" infra red, which is invisible to the human eye. So by illuminating your subject with invisible IR light you will be able to see them via the video camera, although the scene will appear to be in darkness to the naked eye.

Title: how could i make home made night vision glasses?
Post by: another_someone on 19/10/2007 20:35:59

Infra red is totally different from image intensifiers.

Cannot see how you can possibly have a passive image intensifier, since one has to ask where the increased energy in the image came from.

I suspect most modern (and relatively cheap) image intensifiers are just hypersensitive video cameras; but traditionally they have used technologies such as phosphors that emit electrons in response to light, and then an electric or magnetic field accelerates the electron, and the higher energy electron hits another phosphor that emits a larger amount of light than the light required to eject the electron; or another technique was to use electrically charged metal tubes, insert the electron into tubes, and they will scatter more electrons off the side of the tubes, so you get many electrons out for each one in.

These are recollections from long ago, so maybe someone will correct me if the recollections are wrong.

Title: how could i make home made night vision glasses?
Post by: lyner on 19/10/2007 21:15:04

Yes - image intensifiers amplify and are expensive.  IR sensing with a tv camera is the cheapest way into the business. I remember seeing army surplus IR sights, and you used a strong floodlight with a dirty great thick filter to let only IR through to illuminate the scene.
'Tabby' was the name of the equipment, I think. Good for wildlife watching.