BLIND.....Re: [Laser] medium power IR diode

[Andrew T. Flowers, K0SM]

These are some very good ideas, John.  I've already thought about a 
time-delay warning that gives you a few seconds to take cover before any 
laser emission occurs.  Those of you who have built the little Ramsey 
kits know about the flashing LED that comes on a couple seconds BEFORE 
the laser keys. Obviously when dealing with IR one will need multiple 
levels of this stuff-audio and visual.  If you have some schematics I 
would love to see them, as well as others on the list...

I keep thinking of the macs in my lab asking "Are you sure you want to 
do this?"  And thanks for your concern--it would be very easy for a 
newbie to equate "more power" with "better" :-)

Andy
K0SM

John Schnurer wrote:

>
>	SO:	Some of the device protection method I came up with:
>
>	1]	Simple cut-off, fails in the OFF mode.
>	2]	Detector system... if the detector sees ANY of the
>radiation, then OFF..... and locks out until re set intentionally ....
>again... lock out-fail in OFF.
>
>	3]	Emitter tied to laser that points in same general or exact
>direction .... and this is a "safe emitter" ...maybe visible and visible
>with IR at low level.....
>	When you decide to "turn it on" ...  the Safe Emitter comes on....
>then MAYBE you can see if you are going to kazchang someone's eye....
>	and then AFTER you have checked... you over-ride the over-ride.
>
>	Let me know if you want some help with people design.
>
>	4]	One general addition is a sensitive passive IR detector...
>that is overlapping and aimed at any place  person would be ....
>
>	(A)
>	The system goes off if ANY of the elements to be listed below
>triggers:
>
>	IR from source, from sensitive passive IR detector, from safe
>emitter.....
>
>	(B)
>	And these feed to FAST cut-off ......positive feedback IGBT
>hold-off/turn off.
>
>	(C)
>	laser power on activates 3 (THREE!!!) stages of audio and visual
>pilot lights and AND and sound.... you have to do some checks before you
>can "light up the laser"
>
>				let me know if I can help.
>
>								JH
>	
>
>
>
>On Wed, 23 Jul 2003, Andrew T. Flowers, K0SM wrote:
>
>>John,
>>
>>Not to worry, I'm fully aware of the danger of such a beast.  Quite 
>>honestly, I don't want to be using this fully collimated into a tiny 
>>beam at 100mw.  It should be possible to operate this a little above Ith 
>>to get something in the 40-50mw range (still, not a toy).  Also, I think 
>>I would want some sort of beam expander to reduce the power density in 
>>the near field, just in case.
>>
>>Andy
>>
>>John Schnurer wrote:
>>
>>>	Dear AT.,
>>>
>>>	I will try to write some more on the topic, but at 50 mw IR lasers
>>>are not toys.... at 100 mw plus, you can do permanent damage to your eyes
>>>VERY easily by accidental specular incidence on a wide range of
>>>surfaces...
>>>	This can REALLY ding your eyes and the eyes of OTHERS in 100
>>>milliseconds and less.
>>>
>>>	We all might do well to help design a "safe-switch" that
>>>interrupts power under a number of overlapping conditions.
>>>
>>
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