Simple detector that detects "breaking of a line"
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I have been looking for some simple detector/sensor to use in doorways just to detect if something steps through. I would want a narrow beam so that I can use multiple close together.
I thought that it would be easy to find ir sensors for this that just sends out a beam and gets a signal if something breaks the line. But most ir sensors I found either have very small detection range like 1.5 cm or is pretty bulky / expensive and have different minimum ranges. The power draw seams to be somewhat big to like 50-250mA.
I th n looked at those standard ultrasonic sensors witch also seams to detect in a pretty narrow "beam" and have ranges from like 3-300cm and only consumes a couple of uA. Can I place two or more to of the ultrasonic sensor close together or will they interfere with each other? What would the minimum distance be in this case?
Or have I missed something, are there simple ir sensors or similar that sends out a beam that detects if something breaks the line and are pretty cheap and does not draw much power?
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How about a laser pointer and a LDR?
http://www.ebay.com/itm/261977613858
http://www.ebay.com/itm/20Pcs-Photoresistor-LDR-CDS-5mm-Light-Dependent-Resistor-Sensor-GL5516-Arduino-/262136737294Put on your best tights and you'd get something like this https://www.youtube.com/watch?v=KX2_LCUkhDs
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Yes that looks like a pretty cheap solution, only probem is the wiring where I would need a second set of wires as components needs to be on both sides of the doorway.
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@Cliff-Karlsson yes. Or use a mirror.
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@Cliff-Karlsson
Of course, that laser thing is mandatory for every geek (yes, I have to build one myself sometime). But apart from that, are you sure that you've come to the end in your attempts using the common PIRs for this? As I see it, it should just be a matter optics.
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@m26872 said:
s, I have to build one myself sometime). But apart from that, are you sure that you've come to the end in your attempts using the common PIRs for this? As I see it, it should
Yes I thought of that to and I might be totaly wrong but looking at the "ordinary" PIR build
One of the things that made me think of going for another sensor is the trigger time. I found no setting at all on the mini PIR and on the regular the minimum trigger time was something like 10s or similar. I would need a trigger time of ~1s as I want to be able to detect if more then one person steps through a doorway.
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@Cliff-Karlsson Ok, I see. And agree, the PIRs are probably not best/easiest for this. Though, I would call it retrigger or trigger reset time.
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@Cliff-Karlsson I use active beam detector. Power is needed on both sides though but if that is an issue you can always use mirror on the other side. In my experience these things are very sensitive in short ranges (below 5m). More expensive models let you adjust trigger time too.
