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BG2 detection range

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I have read a few posts concerning detection range issues with the new BG2s. The heat this year is going to affect all the boards we use because they detect the differences in temperature along with movement. As it gets hotter the temperature difference between an animal and the surroundings gets less, so the sensor has trouble telling there is something there. It is even more important this time of year to align and space the focal lenses correctly, small errors can make a big difference. Now days a lot of us are using the PT1100 tape to attach the lens to the cases, and this changes the focal distance enough to make a difference in detection range. Even the thinner carpet tape can have an effect. The BG2 seems to be pickier than some of the other boards we use, so I did some testing to see what I could do about it.

 

 

 

What I came up with is this..we just need to follow the specs. on the lens ..duh. The standard lens hags sends with the BG2 calls for a 0.65 focal length. By adding THREE brass washers and the plastic spacer under the stand-off, I have been able to get this very close. This and perfect alignment will improve your range. treetop has a method of aligning the lenses that is very accurate too. He made a jig out of Plexiglas that he mounts to the stand-offs and runs a bit through the center of it in a drill press. I'll let him describe it better. Another way I have found that works well is to drill the 1' inch hole in the case for the lens FIRST, then draw a 1" circle with a protractor, on the template...align the circle with the hole already drilled in the case...then mark and drill the holes for the stand-offs. I have seen the bits "walk" some when drilling the big hole, causing it to be out of alignment. This will help that problem.

 

 

 

I got the thin #4 brass washers at Lowe's, you get 6 in a pack, and you need 9 per cam. Hope this helps :)

 

 

 

 

 

 

 

Put the washers between the stand-off and case...and DO NOT OVER TIGHTEN THE SCREWS.

Edited by 212

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Great work 212, could you do us a favor and mic the thickness of one of those brass washers? just in case we cannot find the same ones in our area, we then know about how thick a washer to look for.

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Pass, I show the stack of three at .067, .022 each, and the plastic spacer hags sends at .065...just about 1/16". A few thousandths should not make much difference :)

 

vman tried his with two of the plastic spacers under each stand-off, and it worked well.

Edited by 212

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Yep...that would make since huh. 7/8 inch stand-offs seem to be a better fit by themselves :)

Edited by 212

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I bought some hard plastic tubing looks like standoffs but is about 10ft long and if a little more flexable I cut my last couple cams standoffs and they seem to work perfectly got the hole 10ft for $2.30 at lowes. maby this will help some also, I dont have a camera here so I cant take pics sorry

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Yep 7/8th is what we need . I believe Hags got the 3/4 by mistake I am sure he will add to this So the easy way for now to build them up is 212s way or my method of screwing on a nut or 2 to get the 7/8th measurement

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Not tryin to jump in here and sound like an ass at all, but this is exactly what I was saying a few months back. You can buy the 4-40 / .875" aluminum standoffs from mouser. Or jump the plastic spacer up to .125", which is exactly what the brass washers are doing.

 

On the BG1 it didn't seem to make much of a difference, at least to the point where people noticed and/or cared. The BG2..... for whatever reason, seems to be less tolerant of the fresnel spacing margin of error.

 

After thinking about it a bit, the best combination may be one .875" (7/8) standoff and one brass washer to get the spacing pretty much dead nuts.

 

hags post

Edited by MIbucks

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If the standard calls for the fresnal to be applied straight to the case and the standoff needed to be 3/4" to acheive the correct distance, this is what needs to be sent in shipping. You can always build up on the standoffs if you used a thicker sealer then just glue but if we were shipped 7/8" or longer standoff and only used glue, those might be too long to work! :unsure:

 

edit: oh and thanks for the information 212!

Edited by bat

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MIbucks is right you know. Bat is too. depends on what you use to mount the lenses :)

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Looks like Dan got the wrong ones from Mouser or they sent the wrong ones.

 

The correct ones are .875 and those are the ones that I use.

 

I put mine out this past week with 108 degree temps and I could detect out to 45 or 50 feet easily. Even further after dark so 90+ feet

 

My guess is this is the problem everyone is having. Please spread the word. Dan will be changing stand offs and sending out extra washers if needed for the already shipped boards.

 

I will start a new post with this topic for those to see.

Edited by Brian

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I'm curious as to why they would need to be different than the BG1. I checked 3 of my BG1s and the all have .75 standoffs. Is the PIR mounted differently on the BG2 than it was on the BG1? I haven't gotten a BG2 yet to compare.

dennbow

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I have always used the .875 on mine. The PIR designs are very very close but just a tad different. I think it is due more to the size and layout of the board than anything. The performance of the BG2 is the same or better when using the .875 standoffs. I have them side by side in my jig and the BG2 to me is more sensitive than my BG1. For some reason though it does seem to be more critical than the BG1 from what I am hearing. I have not seen that in my setups but I haven't used the .75 stand offs either.

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