Lens question.

[Fishbonker]

If you remember from my “First Pics” post my home brew wouldn’t work because I had the PIR sensor off center from the Fresnel lens. I drilled four new holes and corrected the problem. The PIR is dead center on the lens, but it still didn’t sense. I played with everything, wiring, distance from the PIR to the lens and sensitivity. It worked fine outa the case and I could stick my finger between the lens and the board and make it trigger.

I was about to put the entire home brew, case, board, battery and camera on my target out back and sling some .223 at it. Then I thought about why it would trigger the camera in a cheap pencil box case and not the case I’m using now. So I dug up the old case and the first thing I noticed was the Fresnel lens was opaque. The Fresnel lens I used in the new case was clear.

I rummaged around till I found an opaque lens, I pried the clear lens out and glued in the opaque lens. Now It actually works.

So what gives? Why won’t the clear lens work? Both lenses are plastic. For reference, I’m using the RS232 board from PixController. By today’s standards these boards are probably antiques.

I plan doing a side by side comparo, the D40 and my homebrew RS232 with Olympus D360L. I’ll post the results.

Any insight about the lenses?

The ‘Bonker

 

[JNRBRONC]

Are you sure the clear lens is a Fresnel? You didn't buy some clear lenses to go in front of the camera?

 

[vman]

bonk,
The clear lens is a flash enhancer not a frensel lens. SOunds like you got it working though

 

[Fishbonker]

The clear lens has the ridges in it too so I assumed it was a Fresnel lens. The directions, such as they are, said not to use glass infront of the PIR becasue glass would not let infra red through.

Will a round flash enhancer work on a rectangular hole? The enhancer is about 1.25"x1.25" and the lens itself is about 1" diameter. The whole I cut for the flash on my D360L is about 1"x5/8". So to get the efect of the enhancer does the flash have to go throught the entire lens? Would I have to mount it ridges facing outside the case or inside the case?

Thanks guys.

The 'Bonker

 

[TimberSpirit]

Yup that's a flash enhancer. The ridges face inwards just like on the PIR.

Square peg in a round hole no more crazy then some of the other stuff I have read about you doing on here. Sorry could not help myself LOL.

Not sure what will happen but every time I try a flash enhancer it has to much of a spotlight effect for my liking...

 

[Tomo]

[ QUOTE ]
Not sure what will happen but every time I try a flash enhancer it has to much of a spotlight effect for my liking...

[/ QUOTE ]

Yup.

 

[Fishbonker]

Thanks for the info. I imagine if I use the enhancer with a rectangular hole it would make the flash pattern very short making it even more of a "spotlight" effect.

Thanks again.

The 'Bonker