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PostPosted: Thu Nov 30, 2017 12:39 pm 
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Hi Friends ,

I have read some articles on PIR Vs Microwave Vs ultrasonic in general context / security devices .. the only discussion I saw here was in 2012 on x-band microwave .

My PIR is creating a havoc , as in India most of the time and in most places the temperature is above 35 Celsius

Would like to know more with respect to wildlife , PIR Vs Microwave Vs PIR+microwave (dual sensor ) Vs ultrasonic

I have seen some lidar devices but haven't come across ultrasonic camera traps

Pls share your thoughts and recommendation

Thank you



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PostPosted: Thu Nov 30, 2017 1:02 pm 
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PostPosted: Sun Dec 03, 2017 10:21 pm 
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A few quick remarks, based on my somewhat limited experience and knowledge of things electrical. There's no fool proof sensor; the more you work with any one kind the better you'll be able to work around its idiosyncrasies.

AIR: A favorite sensor among DSLR camera trap users is the Trailmaster Active Infrared Trail Monitor, no longer in production, but still available now and then as "pre-owned" devices. Transmitter and receiver are usually set across game trails or wherever an animal is expected. Long battery life, but the electrical cord to the camera is known to attract chewing rodents. At least one French AIR was in production a few years ago.

PIR sensors: They differ among models, Fresnel design, and electrical interface with controllers. Avoid setting the camera in false trigger zones, like reflected light on water, areas with moving sunlight and shadows, hot breezy weather, and direct sunlight on the Fresnel lens. In general false triggers are fewer in cool weather and at night, but sensitivity adjustments can reduce them in daylight to an extent. You just have to work around their individual quirks.

X-band detector (Doppler radar sensor): In my experience it is highly sensitive to any movement, including fast flying insects, but not to moving warm air that so easily triggers PIR sensors. Works best for me (i.e., with fewest false triggers) when aimed vertically at the ground at close range, e.g., when shooting for ground living rodents. You can restrict the detection zone with metal baffles, or a tin can. Power hungry circuitry.

Pixel change detection (as in some IP cams and Canon CHDK mods): Has advantages in the ability to mask areas that cause false triggers (like moving vegetation). Gives good results when you have a small motionless area (not landscapes or areas with blowing leaves/veg).


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PostPosted: Mon Dec 04, 2017 6:53 am 
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this is interesting guys

I'm glad anjani.singamane started his post and his graph got my attention

@ Emperor: did you build the X-band detector? the circuits I looked on the Internet mentioned 30ma, batts would be pretty "Hungry" for sure


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PostPosted: Mon Dec 04, 2017 9:20 am 
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Using a PIR sensor I build a trigger within a remote box. Used a Pixel Rook flash transmitter to send a signal to a Pixel flash receiver in the camera box. What this did was allow me to place the camera in the best scene, and the trigger where I wanted the game when the photo was taken. Worked for what I wanted, very few false triggers and because the trigger was near the game trail I did not miss any photos.


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PostPosted: Mon Dec 04, 2017 9:58 pm 
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I have 3 Parallax X-band detectors. Haven't made one. I use PIR sensors most of the time.


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PostPosted: Wed Dec 06, 2017 12:32 pm 
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cameratrapcodger wrote:
A few quick remarks, based on my somewhat limited experience and knowledge of things electrical. There's no fool proof sensor; the more you work with any one kind the better you'll be able to work around its idiosyncrasies.

AIR: A favorite sensor among DSLR camera trap users is the Trailmaster Active Infrared Trail Monitor, no longer in production, but still available now and then as "pre-owned" devices. Transmitter and receiver are usually set across game trails or wherever an animal is expected. Long battery life, but the electrical cord to the camera is known to attract chewing rodents. At least one French AIR was in production a few years ago.

PIR sensors: They differ among models, Fresnel design, and electrical interface with controllers. Avoid setting the camera in false trigger zones, like reflected light on water, areas with moving sunlight and shadows, hot breezy weather, and direct sunlight on the Fresnel lens. In general false triggers are fewer in cool weather and at night, but sensitivity adjustments can reduce them in daylight to an extent. You just have to work around their individual quirks.

X-band detector (Doppler radar sensor): In my experience it is highly sensitive to any movement, including fast flying insects, but not to moving warm air that so easily triggers PIR sensors. Works best for me (i.e., with fewest false triggers) when aimed vertically at the ground at close range, e.g., when shooting for ground living rodents. You can restrict the detection zone with metal baffles, or a tin can. Power hungry circuitry.

Pixel change detection (as in some IP cams and Canon CHDK mods): Has advantages in the ability to mask areas that cause false triggers (like moving vegetation). Gives good results when you have a small motionless area (not landscapes or areas with blowing leaves/veg).
Great info thanks a ton :)

Have you used the combo using both PIR and Doppler together , and to trigger a not when both detect movement .. i have seen some home security cameras using this combo .

I was interested in ultrasonic as they have narrow field of view and can avoid false triggers ... But after some reading I realised most of the animals can hear the ultrasonic as it's is emitting 40khz frq and most animals have hearing frequency upto 70khz


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PostPosted: Wed Dec 06, 2017 12:36 pm 
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cameratrapcodger wrote:
A few quick remarks, based on my somewhat limited experience and knowledge of things electrical. There's no fool proof sensor; the more you work with any one kind the better you'll be able to work around its idiosyncrasies.

AIR: A favorite sensor among DSLR camera trap users is the Trailmaster Active Infrared Trail Monitor, no longer in production, but still available now and then as "pre-owned" devices. Transmitter and receiver are usually set across game trails or wherever an animal is expected. Long battery life, but the electrical cord to the camera is known to attract chewing rodents. At least one French AIR was in production a few years ago.

PIR sensors: They differ among models, Fresnel design, and electrical interface with controllers. Avoid setting the camera in false trigger zones, like reflected light on water, areas with moving sunlight and shadows, hot breezy weather, and direct sunlight on the Fresnel lens. In general false triggers are fewer in cool weather and at night, but sensitivity adjustments can reduce them in daylight to an extent. You just have to work around their individual quirks.

X-band detector (Doppler radar sensor): In my experience it is highly sensitive to any movement, including fast flying insects, but not to moving warm air that so easily triggers PIR sensors. Works best for me (i.e., with fewest false triggers) when aimed vertically at the ground at close range, e.g., when shooting for ground living rodents. You can restrict the detection zone with metal baffles, or a tin can. Power hungry circuitry.

Pixel change detection (as in some IP cams and Canon CHDK mods): Has advantages in the ability to mask areas that cause false triggers (like moving vegetation). Gives good results when you have a small motionless area (not landscapes or areas with blowing leaves/veg).
Yes codger .. AIR are nice .. I've built one and it's fantastic .. absolutely no issues with this . My PIR is a havoc ...tried all settings of sensitive , and also tried few units made by diff companies ..but as in India the temp is quite high I'm getting too many false triggers

www.anjanikumar.net


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PostPosted: Wed Dec 06, 2017 6:58 pm 
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Keep experimenting. It's the only way to figure out the quirks of the device. Put a box over the camera in broad daylight, run it for 15 minutes, then remove the box and let it go for another 15 minutes. (Or just cover the sensor with something opaque.) Compare the number of false triggers (FTs) under the two conditions. Try it again in early morning shade (facing north of course), and at night. You may also try it in a building and do the walk test 10 times under differing conditions. This is usually the best one can do to create controlled conditions for testing.

In the field: if possible set the camera in deep shade, like a heavily wooded ravine, pointed north, and see if you get as many FTs as you normally get. They should be reduced in such conditions. You can also experiment with a tube over the Fresnel to limit the field of detection (FOD) to a small area. This also prevents light from striking the PIR, which always produces FTs. Compare the FTs with and without the tube. The tube should reduce false triggers as long as there is no dappled light or moving vegetation in the FOD. However hot breezes will still cause FTs.

False triggers are generally much reduced at night, unless there is a lot of rodent activity. Experiment until you start to see patterns of response and can predict the PIR's behavior. The electronics are doing their job, but in addition to warm-bodied animals PIR sensors react to many conditions that are real but we just can't see.


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PostPosted: Sun Dec 10, 2017 4:00 am 
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cameratrapcodger wrote:
Keep experimenting. It's the only way to figure out the quirks of the device. Put a box over the camera in broad daylight, run it for 15 minutes, then remove the box and let it go for another 15 minutes. (Or just cover the sensor with something opaque.) Compare the number of false triggers (FTs) under the two conditions. Try it again in early morning shade (facing north of course), and at night. You may also try it in a building and do the walk test 10 times under differing conditions. This is usually the best one can do to create controlled conditions for testing.

In the field: if possible set the camera in deep shade, like a heavily wooded ravine, pointed north, and see if you get as many FTs as you normally get. They should be reduced in such conditions. You can also experiment with a tube over the Fresnel to limit the field of detection (FOD) to a small area. This also prevents light from striking the PIR, which always produces FTs. Compare the FTs with and without the tube. The tube should reduce false triggers as long as there is no dappled light or moving vegetation in the FOD. However hot breezes will still cause FTs.

False triggers are generally much reduced at night, unless there is a lot of rodent activity. Experiment until you start to see patterns of response and can predict the PIR's behavior. The electronics are doing their job, but in addition to warm-bodied animals PIR sensors react to many conditions that are real but we just can't see.
Thanks a lot codger :) I'm trying all the stuff you mentioned .. will update soon ..thanks :)

www.anjanikumar.net


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