I need a good IR absorbing surface

I bought today a "hands free" garbage can for the kitchen. It said on the box that it has a motion detector for hands free operation. The
unit as a whole is well made and has features I like. The problem is that when slid under the counter the motion detector detects the underside of the counter and the lid opens and stays open. So it must detect reflected IR, whether moving or not. The under counter position is where it must go. The hands free opening is why I bought it, it is for use in the kitchen. All the electronics are in the top, which comes off in order to remove the garbage receptacle. So I need some sort of sheet IR absorber so that the thing will work properly under the counter. I can operate it manually but I don't want to touch the garbage can when I'm cooking and have food of one sort or another stuck to my fingers. Anybody have any ideas? I thought about maybe taking the thing apart and putting a mirror inside that would make the sensor see at an angle so that it wouldn't detect the underside of the countertop but then it might open when someone walks past. So it looks like what I really is a good IR absorbing material that I can fasten somehow to the countertop underside. Any suggestions? Thanks, Eric
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On 7/14/2015 7:12 PM, snipped-for-privacy@whidbey.com wrote:

How about putting the mirror under the counter top?
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On Tuesday, July 14, 2015 at 7:51:32 PM UTC-4, Bob Engelhardt wrote:

I would try some aluminum foil taped under the counter top.
If you really need an adsorber, you could try some black paint. I would try black paint on cardboard before painting the underside of the counter.
How about a make and model? The manufacturer might have some info that would help figure out a solution.
Dan
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Don's got it - IR is what you feel as heat. Heat rays. metal might reflect it unless it were etched and ready to absorb. I'd try the black paint and the cardboard idea is spot on. If it doesn't work then apply another material. A rug would be good, but grabs dirt. Martin
On 7/14/2015 7:19 PM, snipped-for-privacy@krl.org wrote:

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...not as likely to, upside-down over the top of the thing.
But any _really_flat_black surface ought to work. "Just black paint" might not... even some of the 'flats' are kind of glossy. But something sooty black will likely work quite well... unless it ends up heating to the point of re-radiating that IR!
In that case, a heat-conductive underlayment is called for, to move the warmth away from the hot-spot. I'd be tempted to try a heavily-sooted sheet of aluminum. It'll never be touched up there.
Black velvet might work, too.
Lloyd
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"Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> wrote in message

And if it doesn't you can always just drink it. Then you won't care.
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On Wednesday, July 15, 2015 at 4:02:09 PM UTC-4, Bob La Londe wrote:

Drink Black Velvet? There are plenty of recipes for Black Velvet Cake.
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On Tue, 14 Jul 2015 17:19:12 -0700 (PDT), " snipped-for-privacy@krl.org"

Greetings Dan and Bob, I thought of this and tried the aluminum foil thing last night when I got home and could only make it work when it was angled nearly 45 degrees and I'm looking for a flat solution. Thanks for the suggestions though. Eric
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    Not likely any good.

    You want flat black, not shiny.
    And start out with some thing like a sheet of black velvet which should be a pretty good absorber.
    Good Luck,         DoN.
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On 7/14/2015 4:12 PM, snipped-for-privacy@whidbey.com wrote:

Get out your digital camera and take a look to see where the light comes out and the pattern on the underside of the counter. You may be able to mask the light source. You can use the camera to look at reflectivity of various surfaces. The TV remote makes a usable source of infrared.
The camera is not very sensitive in the infrared, but often good enough to do the job.
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That's a great idea Mike. I have a digital camera I modified to see only NIR so it should great. Then I can maybe use black paper like Dan suggested. Eric
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On 7/15/2015 8:45 AM, snipped-for-privacy@whidbey.com wrote:

I still think you're attacking the wrong end of the problem. If you can mask or reflect right at the source, you won't need any absorber. I have a motion detector light that was always triggering when I didn't want. I put some black tape along the side of the emitter to restrict the angle (field of view). Worked great.
I'm still confused about why it matters what reflects as long as it isn't moving. Typical PIR projects multiple images onto the sensor. It triggers when there's amplitude modulation produced by changing patterns as something moves in range.
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Even though the thing says it is motion activated I think it just detects its own reflected light because when the garbage can is slid under the counter the lid opens and stays open. No motion required. So I think it does not have a PIR detector but instead sends out pulsed IR and when it is reflected back the lid opens. Just holding my hand over it will cause the lid to open and stay open. Eric
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On Tue, 14 Jul 2015 16:12:49 -0700, etpm wrote:

Try black cardboard. Most things that look black in visible light look black in IR, too (not everything, but most).
If it mostly works but still false-alarms, fold the cardboard into a fan- fold shape.
If that doesn't work, I'll give you a full refund of all charges for writing this post.
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Tim Wescott
Wescott Design Services
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On Tue, 14 Jul 2015 19:45:41 -0500, Tim Wescott

Greetings Tim, Mike suggested using a digital camera to look at the spot projected by the garbage can. So I'm going to use the same camera to look at paper and fabrics at the local crafts store. When I find something that looks black to my IR sensitive camera I'll buy it. Cheers, Eric
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On Wed, 15 Jul 2015 08:49:10 -0700, etpm wrote:

Be sure to check how reflective it is when the light strikes it at an oblique angle -- black and smooth can be dismayingly reflective, which is why the insides of cameras are painted _flat_ black. Black and stair- stepped can be less reflective than black and smooth.
Come to think of it, black felt may be best, if you're in a fabric store anyway.
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wrote:

That's what I'm thinking. Black felt opr black construction paper. My camera should be able to tell me how reflective something is. Eric
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On Tue, 14 Jul 2015 16:12:49 -0700, snipped-for-privacy@whidbey.com wrote:

Isn't it good enough looking to be left out while you cook?
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On Tue, 14 Jul 2015 18:54:32 -0700, Larry Jaques

The garbage can is always out in the open on three sides. At one end of the counter the countertop extends past the cupboard and this is where the garbage can goes. Out of the way but very accessible. Eric
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On Wed, 15 Jul 2015 08:51:51 -0700, snipped-for-privacy@whidbey.com wrote:

OK. How about screwing a Z shaped paddle onto the lid by the sensor? Construct of sheetmetal and coat with spray-on auto undercoating, with 4-6" for your hand to swipe the sensor. Or just undercoat the underside of the offending cabinet?
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