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Topic Title: Mounting a beam reflection detector
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Created On: 15 April 2018 09:14 AM
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 15 April 2018 09:14 AM
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dickllewellyn

Posts: 1430
Joined: 19 March 2010

Morning All

This relates to the garden lighting project I mentioned recently on another thread.

The lighting design has various lights to be brought on by sensors by the house and at the gate. The gate is set back some 3 meters from the road with a little gravel area between the gate and the road, but I was worried about a PIR receiving false detection from passing traffic or cars using the gravel as a passing place. My idea was to set a beam reflection detector back from the road say a meter out from the gate, so that it is triggered only when a car or pedestrian actually approaches the gate.

Each side of the gate is a low grass bank where I thought perhaps I could use some kind of spike each side to mount the detector and the reflector, but it will have to be something fairly substantial so as not to be knocked or moved by the gardeners. Can anyone point me to an off the shelf product that matches this description? Or recommend a similar idea they have carried out themselves? I may be able to mount on the iron railing fence, but I think that would put the sensor and reflector out of range from one another.

Alternatively I can go back to the PIR idea and just try to find something I can mount somewhere suitable (there's not really anywhere except trees or the fence!) I'm using a Loxone system for the switching, so I may be picking the collective brain for good quality discreet 24v PIRs.

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Regards
Richard (Dick)

"Insert words of wisdom and/or witty pun here"
 15 April 2018 09:58 AM
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Jaymack

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Originally posted by: dickllewellyn
The gate is set back some 3 meters from the road

Less than a metre then, but so short? PIR's with timers are available.

Regards
 15 April 2018 10:29 AM
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dickllewellyn

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Originally posted by: Jaymack

Originally posted by: dickllewellyn

The gate is set back some 3 meters from the road


Less than a metre then, but so short? PIR's with timers are available.



Regards


Thanks Jaymack

I'm quite aware there are PIRs available with timers. Specifically I would like a 24v sensor which can be discreetly mounted and not cause false triggers. The sensor will bring on a lighting scene comprising 2 lights at the gate, 12 lights along the drive, 8 in a path, a further 12 around a courtyard, and 3 on a car port. I don't want a car pulling into the mouth of the drive to allow another vehicle past on the single track road to trigger the scene every time, and hence the need for a more targeted approach. We do indeed have timer PIRs around the house to bring the scene on from the other direction, albeit set to 1 second to provide a pulse to the Loxone and allow the logic to dictate duration.

-------------------------
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Richard (Dick)

"Insert words of wisdom and/or witty pun here"
 15 April 2018 10:54 AM
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perspicacious

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Less than a metre then, but so short?

That one wasn't detected!

Regards

BOD
 15 April 2018 11:12 AM
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AJJewsbury

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Are you thinking of something like this: http://uk.rs-online.com/web/p/...imity-sensors/0519400/ ? (possibly easier to setup than a single headed type with a reflector, although would require more wiring)

Although I would have thought that an ordinary PIR looking sideways across the path and "blinded" on the road half would have worked just as well.

Or maybe easier would be a simple contact switch on the gate itself (i.e. a weatherproof version of the reed switch contacts used on doors for intruder alarm systems) - that should avoid almost all false triggers. Perhaps something like this: http://uk.rs-online.com/web/p/reed-switches/0339746/

- Andy.
 15 April 2018 11:57 AM
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mapj1

Posts: 10798
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I have used refection sensors before and the 'corner cube' reflectors don't need to be pointing perfectly the right way like a mirror would, just be in the beam and roughly in-line.
Outdoors I have driven in short lengths (< 1m )of scaff pole so less than a foot was showing, and then bolted boxes to them. Painted black or camouflage colours they can be hidden from obvious view, and are kick proof. Proof against vehicle strike may be harder.

I can imagine that approach would also be OK in a flower bed (so long as flowers are not in the beam.. )

-------------------------
regards Mike
 15 April 2018 03:50 PM
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rocknroll

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What you need is a 'photoelectric beam sensor', I have one and work remarkably well, you can use them for whatever you like as they operate from 12-230V AC or DC and come with a NC and NO terminals, although I have mine linked to a Pi3 so I can view anything on a iPhone/pad and other messing about with time lapse you can use them for lights, fixed camera, door bell or even opening the gate, dont buy a cheap one though mine was about £140.

PS they generally operate ok from anywhere from 10 - 20 metres.

Regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
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"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
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 15 April 2018 07:07 PM
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dickllewellyn

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This is the sensor I'll be using
https://www.schneider-electric.com/en/product/XUK1ARCNL2/photo-electric-sensor---xuk---reflex---sn-7m---24..240vac-dc---cable-2m/

I did think about a contact on the gate, but ideally I'd like the lights on before the gate opens to illuminate the intercom and code panel.

I like the scaffold pole idea, I hadn't thought much beyond uni-strut which I thought might look a bit industrial!

-------------------------
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Richard (Dick)

"Insert words of wisdom and/or witty pun here"
 15 April 2018 08:05 PM
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mapj1

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that Telemechanique one is very similar to the on I used, whcih was a Siemens part- although it is water proof on its own, I mounted it on a plate in a box with one side windowed, and that allowed me to mess about with bolts and spacers to set the beam angle to strike the reflector, without moving the post or box itself.

The other post just needs a couple of reflectors

Those corner cube dents in the back of the plastic make it less important how well that end is set up, as whatever direction it comes from, it gets sent back that way.
The

-------------------------
regards Mike


Edited: 15 April 2018 at 08:11 PM by mapj1
 15 April 2018 09:09 PM
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Timeserved

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Joined: 18 October 2016

Set of intruder los beams. You could provide a trig voltage for a relay and basically do whatever you want after that.

Ts
 05 June 2018 10:24 AM
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dickllewellyn

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In case it's of interest

I played around with a beam reflection sensor, it seemed to do what I wanted it to do, everything looked good, until the gardener came along and pulled the spike out to cut the grass and left it led on the bank. In fairness to the gardener, we decided to keep long leads above ground on the spike lights for just that reason, so I guess he's not entirely to blame!

Long story short, I contacted Danlers in the end who made me some 24v versions of their little COPD detectors which seem to be brilliant!

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Richard (Dick)

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 05 June 2018 01:13 PM
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mapj1

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Ah, no accounting for human factors ;D

-------------------------
regards Mike
 05 June 2018 03:20 PM
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WiredScience

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How about one or more CCTV cameras linked to a DVR? You could set the the motion detection area of interest e.g. the 1m from the perimeter and use the motion detection alarm output to trigger your lighting scheme. Even the budget systems usually have this sort of functionality.
 06 June 2018 08:08 AM
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dickllewellyn

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Joined: 19 March 2010

Hi Wired science. That's a really interesting idea. I might have a play with that in the future. I'm not too geared up on network commands, so I tend to stick to solid state sensors and switches, but I guess I need to learn the future eventually!

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Regards
Richard (Dick)

"Insert words of wisdom and/or witty pun here"
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