I am wondering if Ir is dangerous,
what you guys think

http://tldp.org/HOWTO/Infrared-HOWTO/infrared-howto-a-eye-safety.html

Opinion ...
It would be an issue, if any, with a DI setup. DI would have the most chance to let IR light escape the box and be in the ambient light reaching your retina. FTIR on the other hand may let a bit of scattered, low angle light get out, but not as much as DI.
I would venture to guess that a whole day outdoors in sunlight, with sunglasses that let the iris dialate just like in a dim room, would allow a far greater amount of IR radiation into the eye than 2 or 3 hours in front of an MT table.

Of course, all of this could be easily rectfied with an IR filter built into the MT table which would also shield you from any possible IR from the projector bulb!
(^;

thanks
can it be made with out IR LED
or lasser. 
to have this kind of table is great but concerning.

The benefit of IR is that most ambient light isn’t IR so the only IR that the camera sees is from the LEDs.
When you build a table that doesn’t use IR, you’re probably using regular light. The camera will see this light in your table, but it will also see your face and everything else that is lit up.
IR doesn’t light up your face the same way. The projector would also be causing problems.

So the answer is probably no. You can’t build a very effective table without IR. You could use Capacitance Testing, but it’s much more complicated.

If you’re interested, then you might want to see this page.

Very intressting topic.
I’m planning to create a DI setup and was also thinking about the quantity of IR light.
To bad there’s so little information on this topic ....

thank you.
great support

principaly the IR LASSER

im suprised because searching a ir lasser in internet i see how lassers can cut iron :S

see ya

Knowledge is power

Remember, we’re working with near infra-red. Far infra-red is what produces more heat and causes more damage.
It’s about exposure and duration. The greatist risk is still posed by a DI setup unless you have a filtering layer on the acrylic or above it.
I would think that this would be a smart feature to incorporate into all IR based MT tables.

Here’s some real data I found on IR and the eyeballs:

A PRELIMINARY INVESTIGATION OF THE EFFECTS OF NEAR INFRARED RADIATION ON VISUAL PERFORMANCE
http://stinet.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0703613

Ultraviolet, visible and infrared radiation hazards
http://www.twi.co.uk/j32k/protected/band_13/faq_radiation.html

THERMAL EFFECT OF INFRA-RED RADIATION ON THE EYE: A STUDY BASED ON A MODEL
http://annhyg.oxfordjournals.org/cgi/content/abstract/35/1/1?ck=nck

it seems that IR is dangerous.
how can this be fix .

It’s been a few years , but I had a friend in college who melted her contacts to her eyes. She was working with either infra or UV (memory fails) but the end result was due to not observing proper safety protocols. (As memory serves, eye protection was all she needed, a pair of safety glasses with filter)

If you are working with a LASER - then make darn sure that you are using PROPER EYE PROTECTION. DO NOT LOOK AT THE LASER!!!!, Make sure that the light is contained/aimed in such a way around your screen that it doesn’t shine directly on any eyes. Once you diffuse the beam with your finger or cylinder lens, not so bad, but looking at an intact IR laser beam is a recipe for pain.

If you are working with regular infraLEDs then it’s less of an issue, the light is generally diffused and not of sufficient quantity to damage your eyes. Having said that - I’m sure some superhero of a modder could put enough infraLEDs together to not only cook their eyes, but breakfast as well.

balam - 05 June 2008 11:12 AM

it seems that IR is dangerous.
how can this be fix .

Yes it CAN be harmful in long term high mW output at close range directly into the eye.

I really do not think that the amount of IR light spilling out of a FTIR style MT table is not nearly that strong. The table I’m building has a radiant output of 1.4 watts. Most of that energy is trapped in the acrylic as in Frustrated Total Internal Reflection.

Tell you what, let’s get scientific about it. After I build my table this weekend, I’ll power it up and look at it with my IR cam and see just how much IR light spills out.

You are wise to be cautious though balam, and it would be good to know some real quantative limit to what is safe for the eye.

I can wait to hear from your data tinkerman.

I asked this question to my professor when I was doing my final installation project in University too.
Alot of IR outdoor you can view that by pointing your cam outside even in a cloudy day. General security use IR emitter if well diffused is said to be safe. Just compare with the outdoor IR intensity, then you will know that safe or not safe.

The sun itself puts out an incredible amount more than what we are. There really shouldn’t be any hard in using IR for our purpose. We’re not putting anything near what’s already out there by the sun, light bulbs, etc. Also, in each MT technique, none of the light is coming you without being diffused and scattered in some way. The laser would be the most dangerous especially if used in a beam that wasn’t scattered.

I saw some people experimenting with IR blocking foil.
Maybe a good solution ?

I tested my MT table today for the first time. I have plenty of IR light!!  Good solid blobs all over the surface shining back through drafting vellum and a mirror.

BUT… I was working in a room this morning that was getting ambient outdoor sunlight filtering in through the eastern exposed window blinds.
It was a partly cloudy morning and every time the sun came out, the ambient IR light COMPLETLY flooded the CCD of my camera and just blew out any blob detection.

So my conclusion is that ambient IR light from the sun is much much stronger than my 88 IR LEDs which total 1.4 watts radiant of radiant energy.
Not the most scientific experiment I know… no control camera setup etc., but based on these observations, I am now of the opinion that the IR light we are working with here is safe on our eyeballs.