Re: gEDA-user: sparkfun 4 layer boards

[Eric Brombaugh <ebrombaugh1@xxxxxxx>]

Dave McGuire wrote:
> On Aug 23, 2008, at 1:52 PM, Dave N6NZ wrote:
>> So, how much mileage could we get out of a cheap digital camera and
>> replaced the IR blocking filter with a visible light reducing filter?
>> There might be a cheap hackable camera that is suitable, since a  
>> lot of
>> the low-end imagers are quite sensitive in IR.  Old camcorders  
>> might be
>> another bet.
> 
>    I'd be shocked and amazed if they could detect thermal IR.

Agree - there's a big difference between the short-wave IR that's used 
by common IR remote controls (which is easily seen on most any webcam) 
and the long-wave IR used in thermal imaging.

You might be able to get a cheap CMOS imager to do it, but you'd 
probably need a fairly unobtainium long-wave IR filter, and possibly 
some sort of cooling rig. Maybe mount it on a Peltier junction - of 
course then you'd need some crazy insulation & sealing to keep it from 
frosting over. Gets complicated pretty fast.

Go here for more info on thermal imaging:

http://www.electrophysics.com/

Looks like most of their stuff works in the 7 - 14 micron wavelength.

I've got an inexpensive IR thermometer though - $25 from SparkFun:

http://www.sparkfun.com/commerce/product_info.php?products_id=86

You might be able to use something like that to hunt down hotspots, 
except that the response time is slow enough it would get pretty tedious.

Eric


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