"Camera trap" security design

I’ve scoured the Interwebs and this forum and was surprised to find very little information on how to build such a thing.

I live in the woods and suspect somebody’s been messing with my stuff. I’d like to build a system to record photos when a person or car entered my driveway. I would like to use an IR beam because PIR’s will not work well in our very brushy, leafy yard. We also have a lot of small critters that set them off.

  1. Will the reflector/IR beam system work OK? I can use a fairly large battery if needed, and the distance would be about 14 feet x 2 (or 8.5m). In daylight would I need a super bright LED? Is this a bad idea in general?

  2. I have old Canon digicams around. Can’t figure out how to keep them “awake,” though, so there is very little delay between trigger and photo being taken. I love Canons but they have one dumb design flaw – the external remote jack is also used for external power! I’d have to dig into the camera to use both at the same time. Maybe another brand?

My wife has a new Canon that turns on and takes a photo in about three seconds; that would work if I could get the camera far enough down the driveway to not miss the moving person/object doing the triggering.

Maybe one of you has done somthing like this and I just couldn’t find it. Search terms are “camera trap,” and also “trail camera” for commercial units. All those use PIR, though.


I have old Canon digicams around.

See if CHDK will do the whole job.

Have you seen the Trigger Trap?

How about laptop plus webcam plus motion detection software? You can get freeware that is configurable in terms of the area scanned for motion and the sensitivity to motion within that area, that does various stuff when triggered such as record pictures/video, send emails etc. Of course you need to make sure the laptop itself is secure and protected from the environment, and provide power for it. But it's something available off the shelf using bog standard hardware, which is always a plus.

With respect to your question 1., IR LEDs come in 5mm sizes that use 100ma. Your 14' one way would be right about at the limit for that. I do not think you could use a mirror for ~28'. If you need more range I would recommend a laser scavenged from a cheap laser pointer. Both solutions assume you're using a 3-pin IR receiver and modulating your LED at ~38khz or such.

I would like to use an IR beam because PIR's will not work well in our very brushy, leafy yard. We also have a lot of small critters that set them off.

Bushes and leaves should not set off PIRs as they are at ambient temprature. If you have small critters, adjust the PIR field of view to a couple feet above ground level.

Thanks for responses.

AWOL, CHDK could be part of a solution, and could even do the motion detection, but with a lot of time spent learning/hacking; here’s a link on that: http://chdk.wikia.com/wiki/UBASIC/Scripts:_Multipurpose_Motion_Detection

zoomkat; thanks, but I’ve never been able to get any sort of off the shelf PIR light to work around my place, they trigger every few minutes, and they stay on constantly on windy nights. We also have lots of bugs, maybe crawling over the sensors? Happens even in winter, though. We’re in s. Illinois, or lot is wild and wooly.

Chagrin, thanks, I suspected that was too long a distance for little IR LED.

Pauly, Triggertrap might do part of the job, but apparently still pre-production.

Much thanks for replies. Maybe I will figure all this out; looks like a challenge!

At the very least I’d like to have a count of entry into our drive, I’m sure I could figure that out.