IR module for camera triggering system

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Hello everyone.

I must begin with an apology for being a total newbie. I've been reading about Arduino for the past two years, thinking about possible applications for my work (photo and video), but I have no practical experience with electronics or robotics. I'm sure the project I have in mind will seem very simple for many of you here, so I hope some of you can help. Here it goes:

I'll be using a camera triggering product called MIOPS Smart which has on-board capabilities to fire a camera's shutter and/or flash as a result of sound activation, changes in light levels (lightning) or laser beam interrupt.

Most interestingly, the MIOPS also provides an extra input (3.5mm jack) that may be used for DIY custom applications with other types of sensors.

I intend to use the MIOPS for nature photography, so in some scenarios laser beam may not be the best option, as it can be seen and may disturb wildlife or show up in the images (also, the MIOPS has an optical sensor for the laser beam, but the emitter has be to sourced elsewhere). I think Infra Red would be better in some situations, or perhaps distance ranging might work. Other options (speculative at this point) would be pressure/weight activation, or humidity activation.

So the idea would be to build some type of Arduino controlled box where I may connect an Infra-Red emitter and sensor with enough distance between them to make an actual path an animal may cross, be it a small insect or a large mammal, and possible using other types of sensors as mentioned, then have the Arduino output a signal to be fed into the MIOPS via the 3.5mm port. There would be no need for the Arduino to control what happens in the camera (triggering, number of shots, interval, is the job of the MIOPS unit).

I now copy relevant instructions for this type of DIY setup from the MIOPS operating manual:

"The DIY port has three terminals. The first terminal is the ground terminal. The ground of the sensor must be connected to this terminal. The second terminal is the signal output terminal. The output signal from your sensor must be connected to this one. The third terminal is the power input terminal. If your sensor requires an external power source to work, MIOPS Smart can provide 3Volts to it through this port. You can feed your sensor from this port by observing the polarity. If the sensor is already powered from another source, you don’t need to make any connection through this terminal. (See diagram attached below).

Please note that, Miops Smart provides 3Volts to the sensor from this jack. The terminal in the front is where Miops Smart will feed the voltage. The output signal of the sensor must be connected to the first terminal of the jack.

The output signal can have a maximum value of 3.3 Volts. Using a sensor with higher voltage can damage the Miops Smart. Please make sure that the output jack of your sensor is compatible with the diagram shown.

After you have made sure, that your sensor has the correct terminal connections, you can connect the jack to the DIY port of the MIOPS Smart. The DIY mode has three different parameters. The first one is the threshold value. It is given in percentage and it reflects the required change in the signal level to initiate a triggering. As the input signal can be anywhere between 0 and 3.3 Volts, one percent change is equal to 0.033 Volts. You can set the threshold value per this calculation. The second parameter is the delay. As in the other modes, you can add some delay to the triggering event. The delay can be set to any value between 0 and 999 milliseconds.

The third parameter is called the “mode”. This parameter specifies how the output signal of the sensor should change to qualify as a trigger event. There are three options: Change, Rising, Falling. If you set the mode to change, it will not matter whether the voltage is going up or down. Any value above the threshold will qualify as a triggering event. If you want to detect increasing voltage only, the mode should be set to rising. And finally, if you set the mode to falling, you will only detect decreasing voltage changes."

That's all from the MIOPS manual.

I look forward to any suggestions for this setup forum members may provide. Thank you all in advance!

MIOPS_sensor_output_jack.gif
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That MIOPS input expects an analog signal, between 0 and 3.3V. If you have a sensor, that operates on 3.3V, you can connect its output to the jack, and power it from the jack. An Arduino may operate on 3.3V (Pro Mini...), but may consume more current than the jack output can provide.

If you want to power the Arduino by 5V, you must turn one of its outputs into kind of "open collector" output. This can be done by connecting the jack signal pin to the jack 3.3V pin by a resistor (1-10k?), and a diode to the Arduino pin (cathode on Arduino pin).

Since the Ardunio only has digital outputs, you can set the trigger level of the MIOPS to 50%, and the Trigger to Falling. Then a high-to-low transition of the digital output will trigger the MIOPS. Take care that the digital output is initially high, after a reset or before connecting to the MIOPS.

1 Like
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Thank you so much DrDietrich for your fast and helpful response.

Would you say then that it would be best to design this system with its own energy source, so as not to depend on the 3 volts the MIOPS can provide?

Also, would the Arduino Pro Mini be your choice for something like this, considering its smaller size?

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Yes, size matters in this kind of application. Pro Mini has also lower power requirement. BTW, how many mA does the MIOPS jack can provide?

Regarding sensors, do you think ultrasound range sensor would scare the animals? It would be easier to place and have an adjustable few meters range. Or PIR motion sensors, should sense anything warm-blooded moving.

I wonder if you really need that MIOPS thing, if camera has any IR remote control arduino could send the trigger signal.

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A look at the data sheet should reveal, how much current can be drawn from the MIOPS. It should be possible to connect a passive IR detector directly.

If you want to build your own trigger system, the smallest available board or controller is sufficient for a simple IR or similar sensor. The Pro Mini can be powered from 3.3V, so that it may be powered from the MIOPS, in detail when sent to sleep between sampling intervals.

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Thanks so much blimpyway and DrDietrich for your help, I really appreciate it.

@blimpyway, the MIOPS manual does not state how many mA the MIOPS jack can provide, I have written to the manufacturer with that question, I hope they reply soon.

I can't give a qualified answer as to which species of mammals would be disturbed by ultrasound, but I'll turn to a few friendly biologists for advice. Thanks for suggesting ultra sound and PIR motion sensors.

One of the things I want to use the system for is insect-in-flight photography at night. I would be using a rectangular frame made of PVC, let's say 36 x 24 cms, to be placed on a stand in front of the camera. Camera would be aimed at the area within frame and prefocused. A long light at the bottom of the frame would be used to attract bugs. Sensors would be installed on the frame, in a curtain or criss-cross pattern, so they trigger the system when an insect flies trough the area of interest. I've seen on the web some systems of this type, mostly using IR beams. I wonder, are there ultrasound or PIR sensors that could be set to such a delimited, reduced area, to be activated by such small critters?

As for needing the MIOPS thing or not, I wouldn't be surprised if they used Arduino to prototype it. However, it would be unrealistic for me at this point to embark on an Arduino adventure and attempt a whole system like that. The MIOPS will provide me with a tool I can use right away for a number of photo applications (not only triggering but also time-lapse and HDR), plus a reason to finally delve into Arduino with more modest goals as stated in this little project, however long that DIY application takes. :slight_smile:

@DrDietrich thanks again for your expert advice. The Pro Mini sounds great, small and can be powered from the 3.3V of the MIOPS. On the other hand, perhaps it'd be best to equip it with its own power source, in order to prolong battery life on the MIOPS?

You also write, "It should be possible to connect a passive IR detector directly", so I've been looking into that. If I understand correctly, what you mean is that the PIR by itself would detect motion and send the trigger signal to the MIOPS, with no need to go through an Arduino? And something similar could also be done with a self-contained photo-gate? Such as a Vernier Sensor Photogate? That would be a very practical solution since the MIOPS will do all the rest, right?

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For insect photography I built a light barrier decades ago, using red LED and phototransistors. The device triggered when e.g. a thin cable was moved through the intersection of the two beams. Dunno how insects reacted on the beams, but the photographer never complained :slight_smile:

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Cheap ultrasound modules work in 40Khz range. Here-s a short list of hearing ranges Hearing range - Wikipedia
Not sure if hearing it is always bad. The ultrasound clicks might attract predators

The (very) cheap PIR sensors I just searched - send a high signal at 3.3V when they detect warm-blooded motion. Not insects, sorry. So yeah, that won't need arduino. But need >4.5V (upto 20). Having low power needs, a 9Vblock battery, a pack of 2 lipos, or 4AA(A) battery pack should work.

regarding avoiding laser diodes for detecting bugs - if they are not connected directly to MIOPS but to arduino, arduino can turn off the laser for a preset time before sending trigger signal to MIOPS.

instead of array of infrared emitters and sensors .. thinking of two narrow long mirrors, facing each other on two opposite sides of the frame - and point the laser so it bounces between mirrors in zig-zag, until it reaches a photo transistor.

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I'm so impressed with this community, thank you both so much for being so willing to help a total neophyte like me. :slight_smile:

@DrDietrich, that's just what I'm thinking for insect insect photography, perhaps using something like adafruit's 5mm IR Break Beam Sensors?.

I'm thinking I would also include dimmable visible light LEDs to lure the insects in, and program the Arduino to switch those off when tripping the shutter, so that only light from my strobes affects the photographs (just as blimpyway suggests doing with laser beams).

One specification I cannot find anywhere is the angle at which these IR emitters put out light, which would be useful to know in order to decide how many sets would be needed and at what distance I should place them to cover the entire frame of interest.

DrDietrich, anything else you may want to share about that light barrier you built for a fellow photographer years ago will be highly valued.

@blimpyway, thanks so much for going the extra mile and searching the web on these topics to help me. So PIR sensors might be the way to go without Arduino for warm blooded animals, thanks for the explanation on power needs. I'm deciding to start with the insect photography rig, and I really like your idea about using a single laser beam with mirrors to create a zig zag pattern all the way to the photo transistor. So nifty!

Again, THANK YOU BOTH!

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Only red LED were available at the time I built that system, nowadays IR LEDs or laser diodes may work better.
For the phototransistors I used BC107 with tops removed, they happened to work on the LED wavelength. Nowadays phototransistors for the emitted (IR) wavelength should be used. Get matching sender/receiver pairs, or decompose a light barrier module to get matched pairs.

The requirement was a narrow crosspoint, according to the low depth of focus of the macro lens. Therefore I put both sender and receiver into tubes of 5mm inner diameter (LED size) and 5cm long, for shaping the beams. Visible beams help to find the crosspoint, or you add LEDs to indicate a break of either beam for adjustment. Then trigger the camera when both beams are broken at the same time, and turn off the LEDs until the image is taken.

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Thank you DrDietrich, I really appreciate your tips. Using 5mm inner diameter tubes answers I question I had yet to ask.

I'm going to attempt some drawings and a list of functions I would like this rig to perform, also a list of parts I'm thinking would be required. Then I'll post again to see what you all think.