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[DPRG] "A great Arduino project for people who really like blinking LEDs."

Subject: [DPRG] "A great Arduino project for people who really like blinking LEDs."
From: Jeff Koenig koenig.jeff at gmail.com
Date: Wed Sep 30 19:53:47 CDT 2009

Interesting, Dale!  If the element can react as quickly as you say, then
nothing complicated may be needed.

I was thinking of doing it asynchronously for the first few pulses, then
after the rough frequency was determined, predict (guess) the leading edge
of the subsequent pulse so the blanking can start before the next pulse
arrives (and remain opaque until after the pulse has gone away).  Measure
the time between the guessed start of the blanking period and the next
actual light pulse, rinse and repeat.

We know the pulses are in the 8-13 Hz range.  I didn't read enough of the
article to know the duty cycle.

Only $50 for a cheap welding helmet, huh?  Hopefully my current project will
be done at the end of October...

-J

On Wed, Sep 30, 2009 at 7:09 PM, Dale Wheat <dale at dalewheat.com> wrote:

> David,
>
> No, the welding masks react to each flash of light, asynchronously.  They
> don't try to match any frequency.
>
> Remember:  Always use your LEDs for good, never for evil.
>
>
> Thanks,
>
> Dale Wheat
>
> (972) 486-1317
> (877) DALE WHEAT
> http://dalewheat.com
>
>
> dpa wrote:
>
>> So then we'd need frequency-hopping on the "weapon."  I feel an arms
>> race coming' on...
>>
>> dpa
>>
>>
>>
>> Dale Wheat wrote:
>>
>>> Jeff,
>>>
>>> When a group of us took welding last January, we were told the element
>>> darkens in a matter of microseconds in even the cheapest units
>>> (~$50).  The higher-end units were rated in nanoseconds, which
>>> everyone knows are too small to actually exist.
>>>
>>> So sure you could easily and inexpensively build a counter-weapon to
>>> this 'bedazzler'.  The trick is to completely seal the optical path as
>>> even reflections seem to have a detrimental physiological effect.
>>>
>>>
>>> Thanks,
>>>
>>> Dale Wheat
>>>
>>> (972) 486-1317
>>> (877) DALE WHEAT
>>> http://dalewheat.com
>>>
>>>
>>> Jeff Koenig wrote:
>>>
>>>> Interesting link!
>>>>
>>>> I suddenly have an urge to modify one of those electronically
>>>> controlled, self darkening welder's masks with a front-mounted
>>>> photodiode sensor.
>>>>
>>>> If the optical element on the mask transitions quickly enough, I bet
>>>> it wouldn't be hard to rig up something that would autoblank an
>>>> offending 8-10 Hz bright light.
>>>>
>>>> Of course, I'd open source it, too.
>>>>
>>>> -Jeff
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Tue, Sep 29, 2009 at 5:21 PM, dpa <dpa at mail.isem.smu.edu
>>>> <mailto:dpa at mail.isem.smu.edu>> wrote:
>>>>
>>>>
>>>>    http://ladyada.net/make/bedazzler/
>>>>
>>>>
>>>>    Dale?
>>>>
>>>>    cheers!
>>>>    dpa
>>>>
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>>>>
>>>>
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