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jack b
Gone Fishing
Premium,MVM
join:2000-09-08
Cape Cod
kudos:1
reply to lutful

Re: Garage door problem

Depending on the garage orientation I would think switching the transmitter with the receiver should eliminate sunlight caused issues. Or, simply glue on a short piece of PVC pipe as a "blinder" to the receiver "eye".
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lutful
... of ideas
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join:2005-06-16
Ottawa, ON
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said by jack b:

Depending on the garage orientation I would think switching the transmitter with the receiver should eliminate sunlight caused issues.

Thank you. I really wanted someone else to point out the ONLY CORRECT position for the IR receiver is where either sunrise or sunset can't interfere with its operation.

It makes no sense to align the beam perfectly using a laser when the sensor was installed on the wrong side.

said by jack b:

Or, simply glue on a short piece of PVC pipe as a "blinder" to the receiver "eye".

Another common sense solution.

Older design IR sensors were not very selective spectrum-wise and needed to be put in a short tube with a very narrow angle lens. But this person still had a problem with the sun and fixed it using a tube from toilet paper roll.

Better designs use IR sensors which are matched to the transmitter wavelength and also modulate the transmitter beam to make sure the system is not confused by external IR sources.


nunya
LXI 483
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O Fallon, MO
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Kind of hard and expensive to reorient my house (faces north). Think about it before saying "it makes no sense". There is no "wrong side". There's either the "deal with it in the morning" side, or "deal with it in the evening side".

It's not as big of a deal to me as it may be to others. I can hold the button down, wait 15 minutes for the sun to move, or have one of my kids stand outside so their shadow is covering the eye.

I'll try the TP tube though. It might work better than my cardboard blinder.
--
If someone refers to herself / himself as a "guru", they probably aren't.

lutful
... of ideas
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Ottawa, ON
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2 edits
said by nunya:

Kind of hard and expensive to reorient my house (faces north).


No need to reorient your house. Just swap receiver and transmitter - many have wing nuts to simply that process. The original installer just did not think about it.

said by nunya:

Think about it before saying "it makes no sense". There is no "wrong side". There's either the "deal with it in the morning" side, or "deal with it in the evening side".

Moving the receiver to avoid potential solar interference around sunrise or sunset would not cause interference during the opposite daily event. That is true for any practical garage design even for perfectly east-west oriented houses located on the equator.


LazMan
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join:2003-03-26
canada

1 recommendation

reply to nunya
Wow - some people just itching for a fight debate around here these days...

robbin
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join:2000-09-21
Leander, TX
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reply to lutful
said by lutful:

said by nunya:

Think about it before saying "it makes no sense". There is no "wrong side". There's either the "deal with it in the morning" side, or "deal with it in the evening side".

Moving the receiver to avoid potential solar interference around sunrise or sunset would not cause interference during the opposite daily event. That is true for any practical garage design even for perfectly east-west oriented houses located on the equator.

Please explain why you believe this

lutful
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Click for full size
Google Sketchup has a sun path simulator which can be used to model the front of a garage in 3D and check this theory.

I drew a quick sketch of how this problem could happen on some setups. The sun's path will be at an angle from the beam's path and the opposite side will not see the sun because of the wall.

With perfect east-west orientation at the equator, the sun's path will actually be blocked by both sides of the garage.

robbin
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join:2000-09-21
Leander, TX
kudos:1
But you are only thinking about a single day of the year. The sun does not rise and set from the same point every day. Therefore what you need to show is that it would be impossible for the rising sun to affect a sensor one day and days or months later the setting sun could not do the same if the sensors were reversed.

lutful
... of ideas
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Ottawa, ON
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said by robbin:

But you are only thinking about a single day of the year.

Curiously I had mentioned Google SketchUp sun path simulator to avoid this type of assumption about my thinking process.

All manufacturers ask installers to choose the least sunny side for the receiver because it can be determined easily and the depth and height of the beam can be adjusted within specified limits to account for both summer and winter.

I previously mentioned that modern sensors modulate the beam to reduce solar interference ... which can also come from shiny garage wall/floor/cabinets.

robbin
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join:2000-09-21
Leander, TX
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There is no least sunny side if the sun rises on one side of the door, shines on it all day, and sets on the other side.

lutful
... of ideas
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Ottawa, ON
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said by robbin:

There is no least sunny side if the sun rises on one side of the door, shines on it all day, and sets on the other side.

You can choose whatever location you want and you will see that there is always a least sunny side. Even in the far north during winter with garage facing due south.

»astro.unl.edu/naap/motion3/anima···ions.swf

robbin
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join:2000-09-21
Leander, TX
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There is always a least sunny side of the house but not necessarily a least sunny side for the garage door opener sensors. The site you linked did nothing to prove your point.

lutful
... of ideas
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Ottawa, ON
kudos:1

1 edit
said by robbin:

There is always a least sunny side of the house but not necessarily a least sunny side for the garage door opener sensors.

That is not actually my choice of words ... imagine you are the installer and you find that instruction in the manual.

Do you have a problem because you are thinking both east and west sides are equally bad for the sensor when a garage door is facing due south in the northern hemisphere?

Or are you having a problem because you realize both sides are equally good since the sun is always outside the sensor's acceptance angle?

said by robbin:

The site you linked did nothing to prove your point.

Check the sun-sensor-source angle at 15 minute intervals between 6am-9am and 4pm-7pm (local time) from September 21 to March 21. The side which ends up with more obtuse angles is the less sunny side ... just for the purpose of proving that point.


Pacrat
Old and Cranky
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Cortland, OH
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Oh hell, guys, it could also be a reflection off a car parked across the street or a house window. Because it is so sporadic, any number of things might be causing it.
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robbin
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join:2000-09-21
Leander, TX
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reply to lutful
said by lutful:

Check the sun-sensor-source angle at 15 minute intervals between 6am-9am and 4pm-7pm (local time) from September 21 to March 21. The side which ends up with more obtuse angles is the less sunny side ... just for the purpose of proving that point.

What good would that do when the sun doesn't set until about 8:30 here in the middle of the summer.

lutful
... of ideas
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Ottawa, ON
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said by robbin:

said by lutful:

Check the sun-sensor-source angle at 15 minute intervals between 6am-9am and 4pm-7pm (local time) from September 21 to March 21. The side which ends up with more obtuse angles is the less sunny side ... just for the purpose of proving that point.

What good would that do when the sun doesn't set until about 8:30 here in the middle of the summer.

I lived in Edmonton (10PM sunsets) for many years and now live in Ottawa (9PM sunsets) ... both cities have many more garages facing due south than any city in Texas.

FYI the summer sun simply can't shine directly on a sensor that is installed just a few inches inside a due south facing garage door. Does not matter if sensor is facing due east or due west.

You can change the start/end dates and also the morning/afternoon windows for collecting the sun-sensor-source angles ... one side will end up with a few more "obtuse" angles than the other. That is the "less sunny side" to install the sensor.

robbin
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Leander, TX
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I'm sure it can't in Canada. I live in Texas at about 30 degrees north Latitude. As you get closer to the Tropic of Cancer, you approach the sun traveling through 180 degrees of the sky. As that happens, it is very possible for the sun to hit one sensor in the morning and the other in the afternoon.

I don't see why the sun cannot shine directly enough on a sensor installed a few inches inside a due south facing door. If it is a double width door then it is 16' or 18' wide. Do the math, the angle it can hit at is within the range of sensitivity of the sensor.


EGeezer
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reply to iLearn
Somehow, I think that two toilet paper rolls (Pringles cans, PVC pipe etc. cut to size) spray-painted flat black inside, and a little duct tape to attach them to the sending and receiving units would alleviate the issue of stray sunlight or transient off-axis reflections.

Or, get fancy and make wall brackets for the tubes using L brackets.
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lutful
... of ideas
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Ottawa, ON
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reply to robbin
said by robbin:

As you get closer to the Tropic of Cancer, you approach the sun traveling through 180 degrees of the sky. As that happens, it is very possible for the sun to hit one sensor in the morning and the other in the afternoon.

You can verify from the shadow cast by the stick figure that it is quite impossible "for the sun to hit one sensor in the morning and the other in the afternoon" ... if you define "hit" as a reasonably small acute angle between sun-sensor-source.

Curiously I grew up in a house near the tropic of cancer. When I was 14, I had the good luck to get my own tiny room on the roof which had one window facing due south. My personal interest in the sun's apparent motion across the sky come from that time and I have done proper sun path analysis (for solar panels) since 2003.


robbin
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join:2000-09-21
Leander, TX
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1 edit
said by lutful:

You can verify from the shadow cast by the stick figure that it is quite impossible "for the sun to hit one sensor in the morning and the other in the afternoon" ... if you define "hit" as a reasonably small acute angle between sun-sensor-source

We aren't debating whether it can do it in a single day, but whether at some point in the year it can affect a sensor on one side of the door and at another point in the year it can affect a sensor on the other side. You are of the opinion that it would be impossible and I think it is possible with the likelyhood greater as you move towards the equator but probably more likely towards the tropical latitudes and diminishing in the equatorial region.

lutful
... of ideas
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Ottawa, ON
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said by robbin:

We aren't debating whether it can do it in a single day, but whether at some point in the year it can affect a sensor on one side of the door and at another point in the year it can affect a sensor on the other side.


Try early morning on June 21 for one side and late afternoon on Dec 21 for other side. Or any other two date pairs when you think the worst case scenario might happen.

Make reasonable assumptions for the location of the sensor (like x=6 inches from garage opening ; y=1 inches towards the side wall ; and z = 6 inches from floor ) and sensor acceptance angle (like 11.25 degrees for a pathetic design).

said by robbin:

You are of the opinion that it would be impossible and I think it is very possible.

If this was just a matter of personal opinion, I would have stopped arguing long ago.

lutful
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Ottawa, ON
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reply to iLearn
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I searched for US regulations re: garage doors because of another thread and found some rules regarding ambient light test.

»law.justia.com/cfr/title16/16-2.···0.1.1.11

Technically, all sensor installations must pass that test which means they can't be affected by early morning or late afternoon sun. Only potential problem for a compliant setup would be reflection from a really shiny floor when the sun is higher up in the sky.

robbin
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join:2000-09-21
Leander, TX
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No, technically the rules you are referring to apply to manufacturer certification of a product

"(a) Purpose. Section 14(a) of the Consumer Product Safety Act, 15 U.S.C. 2063(a), requires every manufacturer (including importers) and private labeler of a product which is subject to a consumer product safety standard to issue a certificate that the product conforms to the applicable standard, and to base that certificate either on a test of each product or on a reasonable testing program. The purpose of this subpart is to establish requirements that manufacturers and importers of automatic residential garage door operators subject to the Safety Standard for Automatic Residential Garage Door Operators"

»www.law.cornell.edu/cfr/text/16/1211.21

lutful
... of ideas
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Ottawa, ON
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said by robbin:

No, technically the rules you are referring to apply to manufacturer certification of a product ...

Since you are determined to be "technical" about this, such a certified sensor system should not fail when exposed to the same or lower intensity light interference in a garage.

garys_2k
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Farmington, MI
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reply to robbin
said by robbin:

said by lutful:

You can verify from the shadow cast by the stick figure that it is quite impossible "for the sun to hit one sensor in the morning and the other in the afternoon" ... if you define "hit" as a reasonably small acute angle between sun-sensor-source

We aren't debating whether it can do it in a single day, but whether at some point in the year it can affect a sensor on one side of the door and at another point in the year it can affect a sensor on the other side. You are of the opinion that it would be impossible and I think it is possible with the likelyhood greater as you move towards the equator but probably more likely towards the tropical latitudes and diminishing in the equatorial region.

Actually, it's more likely the further from the equator you go. Think "midnight sun." A north-facing opening, with one inside wall facing east and the other west will have some days around the equinoxes where light will fall (at a low angle to perpindicular) on one wall in the morning and (on a different day) on the other in the evening.

lutful
... of ideas
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Ottawa, ON
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said by garys_2k:

... north-facing opening, with one inside wall facing east and the other west ...

I understand what you are thinking, but the during the short time when the sun can hit an east-west oriented sensor at a narrow enough angle ... it will probably be blocked by trees and other homes.

Proper installations put the sensor about 6 inches from garage opening and at least 1 inch back towards the wall. That tiny offset will make the (maximum 15 degree wide) viewing cone stay completely within the garage. Properly designed sensors should reject sun-equivalent brightness between 15-20 degrees which also imply rejecting sun interference at higher angles.

The only problem left unconsidered is reflection from a very glossy floor or object coming into the sensor below 20 degrees.
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54067323

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Tuscaloosa, AL

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reply to lutful

Re: Garage door problem

said by lutful:

It is possible that some receivers were assembled with a wide angle lens by mistake. The receiver's acceptance angle can be easily checked.

Garage door detectors have a wide angle for both the transmitter and the receiver to allow for fast aiming with large tolerances, conversely photo beams for security applications have very narrow beam widths, are IR filtered, highly selective and use a pulse modulated scheme to prevent or minimize interference from external sources of IR.