Jonnie Wilson

Fresnal

9 posts in this topic

I have an old build that was given to me for a bit of maintence. It doesn't have a wide angle fresnal lens but a flat one. I set it up beside a build with a wide angle lens and it has no where near the detection range as the wide angle lens. Both builds have snapshot sniper lcd boards and all board settings are identical. one thing I notice is that the bottom two circles of the lens are covered and are wondering if that could be the problem. You can see in the photo. Would it pay to remove the old lens and replace it with a wide angle lens? Thanks

IMG_20170406_161748_zpszvthrxbl.jpg

Share this post


Link to post
Share on other sites
 

I don't see anything in that picture that would substantially decrease detection. Those holes on the bottom that are covered shouldn't affect much. The HPWA does detect better, that's why we use it. Maybe look and make sure that build has the pir centered and that the proper standoffs were used. If you do change it to a HPWA lens you will need to change the standoffs.

Edited by johnnydeerhunter

Share this post


Link to post
Share on other sites
 

I've never used one of these lens's before, it does seem to be centered and without measuring them I would guess that the standoffs are about 1 inch. I think I use 3/8" standoffs with the HPWA.

For this to detect I need to be within 10ft directly in front of it, if i walk past 6ft from the side nothing happens so there must be a problem...just need to figure it out.

Share this post


Link to post
Share on other sites
 

Have you tried a different board battery? Also is the sensitivity set the same on both boards?

Share this post


Link to post
Share on other sites
 

Yes i swapped board batteries and both are over 8V. The sensitivity is set to high on both boards. I also flipped the board and dusted off the pir although I couldn't even see a smudge or speck of dust on it.

I suppose i could swap boards and that may isolate it if the flat fresnal is the problem.

Share this post


Link to post
Share on other sites
 
 

I have both flat wide angle and HPWA Fresnels in builds, they each have advantages and disadvantages. If the detection range is only ten feet there's something wrong beyond the Fresnel. Try cleaning the PIR with denatured alcohol, it might have dust, Goop or fingerprints on it. Also try dialing back the sensitivity adjustment, it make no sense but sometimes the higher it's set the less sensitive it seems to become.

Share this post


Link to post
Share on other sites
 

Ok so I swapped the boards over and the flat fresnal does not work as good as the hpwa. Both boards had sensitivity set to high, I changed the setting for the flat fresnal to very high and then it detected almost as good as the hpwa fresnal. A good outcome I think with nothing more than a little time and help from hag's members. Thank you.

Share this post


Link to post
Share on other sites
 

You're going to have to be careful of false triggers with the board set to very high, I leave mine at normal pretty much all of the time.

Share this post


Link to post
Share on other sites
 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now