Those annoying false pictures

robNhood

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Thanks for the info on the pir in the earlier thread Tinhorn.

If I could just figure what problem I am having with my MS20's. It's probably not a problem at all though. I just had 3 rolls developed yesterday. One cam (PF no date) took all 24 of nothing. By looking at the photos, you can tell that all were taken within minutes of each other. They all looked the same...a bright spot that the sun caused on the weeds in front of the cam. That had to be the problem. When I put the cam out, naturally the bright spot was not there, and as the sun angle changed...Whamo!

Cam two had day, evening and night pics of nothing. Had to be something distant setting it off. That darn thing has too much range I guess. I try to put it where distant shots would not occur but I guess it didn't work.

Cam three had mister squirrel walking on the ground, taking 8 pics. Three deer set it off...great! And several pics of nothing.

I can't blame it on any storms this time. It has to be distance (far animals) and that annoying bright sunspot on the foliage setting them off.

Well, any one else having as many false triggers as me?

I use the tape to narrow down the right and left areas of the pir.  Do not point it directly at the sun. I wonder if I may be putting it a little to low on the tree? 2 ½ feet, and it's getting too much ground heat and close squirrels.

I may modify a cam or two with the RS pir to see if that corrects my problem.

Any suggestions?

This is a cam from last year. Overcast conditions, no foliage and no wind. I think these are our ideal conditions.

I placed this cam higher than I have been this year.

I didn't get any false pics at all with this setup.




(Edited by robNhood at 11:20 am on Sep. 5, 2001)
 

Archilochus

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Hi robNhood,
An easy way to reduce sensitivity on any PIR sensor is to get some PIR window material.  Cut out the right size and keep adding layers of the material until the sensitivity is at the level you need.
Materials for PIR windows can be purchased from Fresnel Technologies, Inc.
< http://www.fresneltech.com >
They do have a 30.00 US$ minimum order - perhaps you and several other MS-20 users could all pitch in and buy a sheet of the stuff.

Archilochus
 

Brian

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Try putting it in a room by itself.  A room where no one will be entering.  Not a metal building.  They can heat up with the sun and cause false triggers.  Leave it for a while and then check and see if there are any picture taken.  If not then everything should be working properly from and electronic standpoint.

I did this when I built my own PIR sensors and found out that the smallest twig or branch or especially grass could set the sensor off.  If the sensitivity(Gain) of the sensor is set high which relates to the distance a PIR can detect then you will get false triggers as the day heats up the surronding vegetation.  This is why I built my own sensor with sensitivity adjustments.  I can then tune them back during the summer to reduce or eliminate false triggers.  If you look at the signal from the PIR on a scope the level for triggering is usually set constant by a voltage divider and the sensitivity is adjusted by adjusting the gain of the first stage of the amplifier.  

After hunting season I may take one of these sensors ya'll are using apart and see if we can add some stuff to reduce the gain manually like the sensors I build.  It is to late this year for me to get into it.  

As the temperatures fall your problems should go away unless you point it into the sun directly.

One of the other guys may have already tackled this problem I am not sure.

Brian
 

bigmandude

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yes,

i am having the same problem only i used a 24 roll at night so i cant blame the sun.  i am blaming the batteries,,,heck, ya gotta blame something.
 

Tinhorn

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MS20 Sensitivity:

The horizontal rows on the PIR Lens govern distance so I experimented taping off the MS20 Rows with black tape over the week end:  Here are the results

Weather: Overcast and about 75 degrees, calm

I had a vertical piece of tape on each side to narrow down the window (3/4&quot

I used a 50' tape laying on the ground and didn't bother testing max range

There are 3 Horizontal rows, the Longest "Boxes" are far the farthest range.

No Rows Taped off----------------45 + feet
Top Row only exposed -----------45 + feet
Middle Row only Exposed---------16 to 20 feet
Bottom Row only exposed -------5 to 6 feet

So during hot weather, if you feel a range of 16 to 20 feet is ok, then taping off the top and bottom rows mightl (should) reduce false alarms

Tinhorn
 

robNhood

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Tinhorn,
I will most definitely give that a try and thanks for all of the hard work. I guess at times, I am so busy with work and other household items, I don’t take the time to tinker like I should.

If I can narrow down the range with your idea, I’ll owe you one
 

Richard Webb

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Another good test Tinhorn....I plan to run mine in middle row only mode except when when I'm working grazing elk.
 

OakridgeBowman

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Hey guys... I'm having the same problems with my PIR sensor. Basically 24 shots of the same spot with no mammals in sight. Judging by the shadows the shots came all through the day and night. We have a lot of bats in the area... I'll try taping the sensor. I'm also getting a fair amount of flash washing into the picture. Any one try leaving the shutter lens completely exposed (ie. drill it out and put a little rim like a baseball cap over the hole?)
 

robNhood

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I cover the flash, not the shutter. Cover the flash inside of your housing so that the flash cannot leak and affect the shutter.

A foam piece of insulation should do the trick.

As far a the range of the MS20 goes, Tinhorn did a great job. Leaving only the center row of the lense exposed keeps my range down to about 20 feet. Try doing that and try mounting your cam about waist high on the tree (3 1/2 feet).

It seems that the lower I mount my cam , the more false pics I have been getting.
 

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