IR sensing to detect insects
IR sensing to detect insects
(OP)
I am interested in detecting insect movement with an IR emitter and detector. I have no experience with designing circuitry and need a good resource that will help me understand what I need in order to make this happen. Any assistance will be appreciated.





RE: IR sensing to detect insects
If I were you I would start by asking IR imaging companies about if their product X can do this.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: IR sensing to detect insects
RE: IR sensing to detect insects
TTFN
RE: IR sensing to detect insects
RE: IR sensing to detect insects
RE: IR sensing to detect insects
Please read my FAQ and give us some DATA.
The task is trivial but you have to define it with NUMBERS
Plesae read FAQ240-1032
My WEB: <http://geocities.com/nbucska/>
RE: IR sensing to detect insects
RE: IR sensing to detect insects
Do you know if the D. is blind for IR ?
May the range of motion limited in vertical direction?
How much positional accuracy do you need?
Can you build the circuit if you get the schematics?
How intensive is the "light situation"? May the
light be fluorescent tube ?( No IR !)
Plesae read FAQ240-1032
My WEB: <http://geocities.com/nbucska/>
RE: IR sensing to detect insects
A quick check of some stocking parts distrubitors uncovered devices like (example): Fairchild Semiconductor H22A4
http://www.fairchildsemi.com/pf/H2/H22A4.html I'm not saying this is the one, just an example.
Check part distributors like www.digikey.com, www.mouser, www.newark.com, www.jameco.com. Use search terms like "opto switch" "Photo interrupter", etc. These sites will have links back to manufacturers data sheets. Then check the manufacturers web sites for applications notes which will give example circuits.
RE: IR sensing to detect insects
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RE: IR sensing to detect insects
RE: IR sensing to detect insects
Those sort of switches are probably designed for something large and solid to block the IR. I wouldn't even assume that they could be reliably adjusted to work (adjusted perhaps, but reliably maybe not).
Also, the glass tube might bring some optical complications. If the IR beam were very narrow, then the tube simplifies into two walls (optically simple). I think most such sensors have larger beam widths.
I don't think it is necessarily as simple a problem as simply using an off-the-shelf photo-interrupter switch. It might be, but perhaps not. Small beam width would help.
If the problem was lab rats in a 10-cm tube, then it really would be easy. But tiny bugs in a 3.18mm ID tube brings a few complications (or at least design risks).
And 'nbucska' had a VERY good (biology) question about the bugs' opinion about 'absolute darkness' versus being blasted with near IR. Camcorders pick-up near IR so it isn't a stretch to wonder about the wee little bugs needing sunglasses.
If you do use optical sensing, maybe it needs to go end-to-end through the length of the tube (with entrance and exit ports for the bugs). Might require custom circuits to be reliable. I'm assuming the bugs have better IR blockage lengthwise. Plus the signal would be longer duration.
Alternate concepts:
Maybe the bugs could walk across a microphone element ('scratch scratch scratch'). Would require a sensitive element, a low noise preamplifer, and a quiet environment. Could use multiple elements and timing/logic to reject ambient noise and determine direction.
Maybe a (very very) sensitive balance (using mass). Tricky.
Maybe ultrasonic Doppler (affect the bugs?).
Maybe vision systems (IR again).
RE: IR sensing to detect insects
Actually I agree with VE1BLL on the run-of-the-mill interrupter switches being iffy.
1) I would design an analog system that essentially looks for a 'dip' in the light as this would allow a fly to walk thru anywhere, upside down, etc and a dip would still occur.
2) I would put two sensors right next to each other and look for the one-two punch,(dip-dip),to confirm Mr. Bugs passage.
3) Consider using reflective technology so the light shines against the bug body and the reflected light confirms bug passage.
4) If any kind of daylight can get anywhere near this system then modulation is absolutely required if you want reliability. With the reflective system you just look on the receiver for the modulation signal to appear,(=bug).
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: IR sensing to detect insects
You'll probably also need to adjust the source current. I'd start at a couple of milliamperes and work up slowly from there.
Daylight and incandescent lights will blind the sensor, fluorescent lights won't. I like the idea of modulating the source and just looking for that frequency on the receiver. You don't need a fancy tuned circuit in the receiver to implement synchrnonous detection, since you've got the modulation signal a few cm away already.
Find a friend who can explain 'synchronous detection' in English and you've got your circuit designer.
Mike Halloran
Pembroke Pines, FL, USA
RE: IR sensing to detect insects
RE: IR sensing to detect insects
RE: IR sensing to detect insects
1. Do you know if the D. is blind for IR ?
IR is used with the flies in similar applications and there is no report that it has any effect on them.
2. May the range of motion limited in vertical direction?
The tubes will be horizontal. They are about 70mm in length. The fly can walk around freely inside the tube. There is no room for it to fly.
3. How much positional accuracy do you need?
Not much is needed. The idea is to see if the fly is moving. It doesn't need to be monitored in an exact location. If it moves close to the detection zone and then turns around but is detected, that is good.
4. Can you build the circuit if you get the schematics?
Yes. I should be able to build it with schematics.
5. How intensive is the "light situation"? May the
light be fluorescent tube ?( No IR !)
I'm told the light cycle does use fluorescent tubes. I'm also told that similar devices use IR detection in the presence of fluorescent light. Based on what you and a couple of other replies mentioned, this should not be the case! Am I getting incorrect information from the fly people? The flies are in a temperature regulated incubator so I'm sure the fluorescent lights are correct. Is there a way to use IR detection in fluorescent light?
Thanks to everyone for the advice.
RE: IR sensing to detect insects
the detection but complicates the circuitry.
If you want to detect the motion -- any motion --
perhaps video camera would be better.
Use -- perhaps vacuum-formed -- mini-Petri- dishes
arranged in an 8 x 8 matrix or it may even be one piece.
the video signal is digitized and iinterface to a PC. The
PC stores the picture in an array form, compares it with
the previous picture pixel -to pixel, and if there
is/isn't any difference, determines its position by cell
number.
You need a cheapest camera and inteface card, off the
shelf, no circuit to build. The software is trivially
simple.
Plesae read FAQ240-1032
My WEB: <http://geocities.com/nbucska/>
RE: IR sensing to detect insects
I'm amazed that nobody has wandered by and suggested RFID tags...
RE: IR sensing to detect insects
The cheapest camera would be OK with a frame grabber.
Plesae read FAQ240-1032
My WEB: <http://geocities.com/nbucska/>
RE: IR sensing to detect insects
Am I understanding correctly that it's impossible to do this with an IR beam in fluorescent light? The lab uses monitors that claim to be using an IR beam to detect the flies. These monitors are used in fluorescent light (or at least that's what I'm told). If someone would clarify that for me I would be grateful. Thanks.
RE: IR sensing to detect insects
I don't know the answer, but wanted to throw the ideas out there for further thought. Either method would remove the need for any illumination at all (IR or otherwise), and would be impervious to any "daytime" lighting.
Dan - Owner
http://www.Hi-TecDesigns.com
RE: IR sensing to detect insects
Re cost: The camera may be the cheapest solution -
just think about the mechanical work of installing
and wiring 50 sets of LED-s,phototransistors,
circuits,computer interfaces, etc. The system would
not detect any motion but only if a D. crosses
the beam.
The tube is 5mm OD, about 3mm ID. If the D. confined
in longitudinal ( relative to the axis of the tube)
direction? Can you design a planar arrangement where
the camera can see all of the cells ?
I don't understand the limitations and without
knowing more, I don't think i can really help.
Plesae read FAQ240-1032
My WEB: <http://geocities.com/nbucska/>
RE: IR sensing to detect insects
RE: IR sensing to detect insects
You shouldn't have a big problem with fluorescent lights.
The key with all optical systems is Signal to Noise ratio SNR. If your IR is the dominant light, from the sensor's point of view, then it will swamp the fluorescent lighting.
Most all IR device makers recognize that the only way to deal with high dynamic light variations is thru the modulation method. Because of this all the different IR comm devices like TV, VCR, DVD, stereos, etc., use this method. In fact they all use the exact same method.(Note: Most houses now have copious fluorescent lighting) This is why all the remotes seem to understand every device out there. What you want to do is piggy back on that knowledge/functionality. You want to use the exact same scheme and modulation technique. I would look for these parts starting with STi corp. You could use for instance a remote control to send an endless stream of "TURN ON TV" or some other short command and detect the signal reflected off of the fly's body.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: IR sensing to detect insects
simple/cheap circuitry.
Plesae read FAQ240-1032
My WEB: <http://geocities.com/nbucska/>
RE: IR sensing to detect insects
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: IR sensing to detect insects
What about a simple laser ($5USD with a fan-shaped beam) and a normal optical sensor. If the little bug crosses the beam, the received light will decrease and some form of software should be able to count that as a hit.
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RE: IR sensing to detect insects
RE: IR sensing to detect insects