Instructables
Picture of Crossed IR Beam Camera/Flash Trigger
This device will trigger a camera or flash unit to automatically take a picture when an object (target) enters a specific location. It uses two, crossed infrared light beams to detect the presence of the target and close a relay that trips the camera or flash unit. Response time is about 2 ms from detection to relay closure, so if your camera doesn't have long shutter-lag, it will capture even fast moving targets.

The optical part of the device consists of two IR LEDs and two Sharp IS471FE optical ICs (OPICs). The optical ICs have built in LED modulators and synchronous detectors, so they won't see light from each other's LEDs. The outputs from the OPICs are connected to an 8 pin PIC microcontroller that handles interpreting input signals and driving the relay and a visible LED that indicates the operating mode. Though there are 11 operating modes, the controller has a very simple user-interface consisting of a pushbutton switch and an LED.

On power up if the beams are properly aligned and unbroken, the LED lights continuously for 1 second then goes dark to indicate the unit is ready to operate in the continuous mode. In that mode the relay will close and remain closed and the LED will light up as long as both IR beams are interrupted. The unit is now ready to connect to your camera.

With some targets you may want to take more than one picture when the target breaks the IR beams. I have included a basic intervalometer function in the controller to allow cameras that don't have a built-in rapid-fire mode to take multiple pictures as long as the IR beams are interrupted. Pushing the mode select button once takes the controller out of continuous mode and puts it in pulse mode. The LED will flash one time to indicate that the relay will close 1 time per second. Some cameras are faster so pushing the button again will move up to 2 pulses per second. By repeatedly pushing the button, the speed will increase from 1 pps all the way to 10 pps, each time flashing the LED to indicate the pulse frequency. Holding the button down for 2.3 seconds resets the unit and takes you back to continuous mode.
 
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recwap3 years ago
DIY arduino based open source advanced photo camera control

CPU 16Mhz Atmega 328
84x48 graphic LCD with backlight
IR & Wire Photo camera trigger
2x Wire Flash Trigger
onboard light/sound sensor or 2x external sensor
2x digital IN/OUT
timelapes function
onboard RTC clock
onboard buzzer

http://www.facebook.com/home.php#!/pages/APCC-Advanced-Photo-Camera-Control/194425487264052?sk=info
LouiseTGUK5 years ago
How small an object would this ir emitter/ sensor detect?

I am hoping to use it to detect water drops, but not in the cross beam setup. I want to use beams separately, one to trigger the camera shutter (1 sec exposure) then another below to fire the flash. As the water drop hits the first the shutter opens, then when it passes the second it will trigger the flash (after a pre set delay).

I will not be using the pic circuit just the emitter/ detectors wired into Arduino inputs.

I am also rather interested in the macro aspect, the possibility of setting it up in cross beam to capture insects would be a very cool thing to play with given that macro is my 'bag' but would it have the resolution to capture the very small?

check out some of my macro work here if you have the time:

http://www.flickr.com/photos/louise-paisley/collections/72157606475942705/
I love macro pics. The drops are cool, so hard to catch.

I wish I was a better photographer, here are mine:

macro shots

<img src="http://lh6.ggpht.com/_ALPVWabsNTI/SuEMzx-56jI/AAAAAAAABFI/V1DeeS3HOJM/s144/Macro%20018.jpg">
Mark Rehorst (author)  LouiseTGUK5 years ago
Wow! I like your macros, especially the ones with the bugs in flight. I like to shoot bugs too, but alas, I live in the desert where there are few bugs to shoot and the heat is so intolerable I can't get out to shoot them anyway. I shot some when I lived in the bug capitol of the US- Northern Missouri. You can see some of them here: http://mark.rehorst.com/Bug_Photos/index.html

Now, to answer your question, the beam that the LEDs produce is pretty wide, at least a few mm, so it might be difficult to get small objects like water drops to break the beams reliably. One solution would be to restrict the light path at the detector. I'd probably just use a couple carefully aligned pinholes at either end of short (maybe 10-20 mm long), blackened tube positioned in front of the detector. Keep the path from the LED to the detector short and it should work.

The same technique could be used to make a small. crossed beam set up for shooting bugs.in macro mode. Depth of field is often so narrow that it may be difficult to ensure that when the beams are broken the target is focused exactly where you need it to be. On the other hand, the beams may make possible shots that would otherwise be nearly impossible to capture, so I think it would be worth trying. Keep in mind the narrower you make the beams the harder it will be to align them.

The path of water drops can be controlled easily so you may be able to just set up two beams, one to trip the shutter and the other to fire a flash, without having to bother with crossed beams.

I look forward to seeing some of your pictures made using the new system.

Cheers!
Thanks for the prompt reply, and the superb instructithingy as well ;) Your bugs in flight put mine to shame :( However, they illustrate nicely what I am thinking of. I could set up an attractant (flower for eg) with the cross beam set up above it or whatever position I think is the most likely in-route for a bug and then go and have a drink and a smoke, catch some rays, take 40 winks, and come back to check who called in at IR central. Not necessarily 'extreme' closeup, maybe as far out as1.5 or 2:1 with the resulting increase in DOF but hopefully on the wing :) I did knock up a quick bread board circuit last night, altho I don't have the same emitter as you. It did work to a degree, sensing objects down to about 3mm but the range was very short.. I could only get about 4 inches max.which I guess is probably down to the emitter, I will have to obtain the same ones as you if I can find a UK source. It would not detect water drops at all, so I will give the pinhole a try over the weekend and see if that helps. I think it may fail due the the emitter I am using as it seems somewhat underpowered as it is so restricting the light to a pinhole there maybe just wont be enough left to trigger the IC.
Mark Rehorst (author)  LouiseTGUK5 years ago
Be sure that your emitter and detector wavelengths match. The OPIC is sensitive to a narrow band of IR wavelengths. I chose the LED in the 'ible to match the OPIC. TD
I did.. 940nm http://www.farnell.com/datasheets/27353.pdf

I am probably doing something else wrong, I am very much a beginner in electronics lol. I am driving it with the 5v output of the Arduino and just feeding the output into a digital in to read the state so just used the sensor page schematic.

Would the absence of D2 & C1 have any impact?
jrig4 years ago
which software did you use to draw the schematic???
Mark Rehorst (author)  jrig4 years ago
 I can't recall what it was.  I am sure it was a freebie though...
madrasi5 years ago
Hello, I know it's been almost A year since your last post to come in but I do have a problem and I hope you can help me. I have a 4 plea cam system that records 24/7 on A time lapse system. What I would like to do is set up some kind of motion detection system on it so that the only time it records is when motion is detected and stops recording after so much time but as far as the monater is concerned I can still see what's going on when its not recording. Would your system help me in that problem or not. Either way I do like your Instructable and I would like to put something like that corner to corner on my property too. Thanks for your time either way and I'll be looking for more from ya. Take care DD
Mark Rehorst (author)  madrasi5 years ago
The range of the LED/opic is limited so you'd have a hard time using it to monitor trespassing. You might be better off using lasers and visible wavelength sensors. As far a motion detection goes, many web cams have that feature built into software for very low cost. The software analyzes the image coming from the camera and when a difference is detected the software starts recording and/or triggers an alarm.
tslibertan6 years ago
Excellent. Last year I made a camera (pulsed laser) trigger for wildlife photography. It had only one beam, and was made out of circuits from Mims' notebooks. 555 ICs etc. It works very well, although it became apparent that a microcontroller would be necessary for anything more sophisticated, and so I've begun to learn about PICs - currently I'm only at the 'flashing LED' stage. It's with great delight that I see your contraption, which even looks a little like mine (hopefully I uploaded a photo). I've stolen your .asm file. Those online timing routines sound like they might be very useful. Cheers.
LTrigger_alone.jpg
In addition to the redness of our knobs, I see that even our confirmation lights and power switches are in the same places. I feel inspired to design (on paper) my dream all-purpose camera trigger. Some more pictures I dug up. Detector, laser and some devices the trigger can fire.
LTrigger_detector.jpgLTrigger_laser.jpgLTrigger_firing_devices.jpg
You can sale it to me?
clamoring6 years ago
Nice use of IR LEDs! Can't wait to see your next project!
Wow... great Instructable! A lot of details, pictures are great, very descriptive, great job, it looks like quite a bit of work, but wow, nice job. +1 rating.
Mark Rehorst (author)  GorillazMiko6 years ago
Thanks! It was a bit of work, mainly figuring out how get the and keep the optical stuff in alignment. I do a lot of stuff with PVC so I decided to try it for this project too. The PIC programming was the easiest part. I'm already looking at adding another operating mode - inverse continuous. The idea is to trip the relay when the beams are NOT interrupted. Then you can put an object such as a frog in the beam area, and catch a picture of him in the air when he jumps. Or maybe a water balloon onto which you drop a dart or other sharp object. When the balloon breaks, it will no longer interrupt the beams and the camera will snap the picture. I think it would be worthwhile to make a smaller optical frame for macro work, maybe one that screws into the tripod socket on the camera. It would probably be great for capturing bugs in the air near flowers, etc. TD
hummingbirds! almost impossible for normal people to reliably capture on film. This would work great for hummingbirds.
coryo936 years ago
Is it fast enough to be able to capture a picture of a moving arrow, as in a bow & arrow, or like a BB from a BB gun?
Mark Rehorst (author)  coryo936 years ago
That depends on a lot of factors. Arrows and BBs are very small objects. You have to break BOTH beams in order to trigger the camera/flash. It would probably be nearly impossible to do it with something as small as BB in the configuration shown. The beams are IR so there's no easy way to check for alignment that is so precise that an object as small as a BB would trigger the thing. The beams may miss each other by a few mm and that would be enough to prevent a BB from ever breaking both beams. An arrow with feathers would probably work. If you want to capture really small stuff, you will need to make the frame assembly smaller so that you will be able to set up and maintain the beam alignment. If you want to capture something moving fast, you'll need to trigger a flash instead of triggering a camera- they usually have long shutter lag and the arrow will be far away by the time the camera snaps the picture. If you set everything up in the dark and use the trigger device to fire a flash unit instead, you'll get a nearly instantaneous flash. Set up the camera bow and arrow, flash and whatever else you may need and kill the lights. Open the camera's shutter, fire the arrow, and close the shutter again. Total delay in the photo trigger device is about 2 ms. You may need a couple test shots to see how far your arrow will go in 2 ms and point your camera and flash there. If the arrow moves at 300 ft/sec, in 2 ms it will go about 0.6 feet. If you rely on the camera's shutter to fire you may have to wait 0.1 seconds- the arrow will go 30 feet. If I wanted to capture a BB or arrow I would probably set up some other trigger device. Maybe a thin plastic membrane with a piezo pick-up attached. Fire the arrow or BB through the plastic and the pickup will generate an electrical signal that will trip a flash unit. TD
Wow. You covered a lot. Thanks. I will look into what you said. Do you know of any instructable that tells you how to created a slow-motion camera like they use on MythBusters?
Mark Rehorst (author)  coryo936 years ago
That would require a video camera that can shoot at higher than normal frame rates. When you play such a video back it then looks like slow motion. I am looking into modifying web cams for variable frame rate video. If I succeed I will write an Instructable. In the meantime, Casio just announced a new digital camera at CES that will be able to shoot at up to 1200 frames per second. See it here:
http://gizmodo.com/341634/casios-exilim-pro-ex+f1-hands+on-1200-fps-demo-video-and-sample-60+shots+per+second-gallery

TD
Thanks. Good luck on building that web-cam one. Really good luck to you, because that Canon camera was $999.99.
Mark Rehorst (author)  coryo936 years ago
None of the currently available web cams will ever be able to shoot that fast. Maybe in ten tears... TD
shaunak6 years ago
Very cool! Clear instructions, nice illustrations. Keep the good work up!
johnpost6 years ago
Awesome Instructable, with in focus photos even. Great project. I'm building one.