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| Science Forum Index » Engineering - Lighting Forum » IR Remote Interference... |
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| EnigmaPaul at (no spam) gmail.com... |
 Posted: Fri Oct 23, 2009 4:06 am |
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Guest
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We're having problems with IR remote controls not working in the room
where there are a number of overhead fluorescent lamps. Obviously
interference with the carrier frequency.
Can we install RFI filters on the ballasts to eliminate. Are there
any other solutions? |
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| TimR... |
| Posted: Fri Oct 23, 2009 6:49 am |
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On Oct 23, 11:34 am, "TKM" <nom... at (no spam) no.net> wrote:
[quote]"EnigmaP... at (no spam) gmail.com" <enigmap... at (no spam) gmail.com> wrote in message
news:9261ecd7-6e78-4e4c-b753-c642d68474f0 at (no spam) g1g2000vbr.googlegroups.com...
We're having problems with IR remote controls not working in the room
where there are a number of overhead fluorescent lamps. Obviously
interference with the carrier frequency.
Can we install RFI filters on the ballasts to eliminate. Are there
any other solutions?
The IR receiver on your electronic device is being swamped with IR signals
from the cathodes of the fluorescent lamps driven by high-frequency
electronic ballasts. It's a known problem.
Anything you can do that will keep the receiver from "seeing" the ends of
the bare fluorescent lamps will help. I haven't tried it, but a simple
visor at the receiver's sensor ought to result in some improvement.
Changing the ballasts to another kind that operate on a different frequency
would do the job too; but you would have to figure out the frequencies.
I don't see how an RFI filter would do anything. The interference is not
traveling via the power line.
Terry McGowan
[/quote]
Yes, exactly.
The lights overload the sensor on the tv set that is supposed to pick
up the signal from the remote.
It happens with CFLs too.
I have seen engineers specify filters and new transformers but of
course it doesn't work. As noted, the interference is light in the
air, not radio waves or electricity. It has nothing to do with
carrier waves, it is just the infrared light from the remote to the
tv.
Last time I was in a motel room where this happened, I put a cardboard
shield over the sensor on the tv. That worked fine. |
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| TKM... |
| Posted: Fri Oct 23, 2009 9:34 am |
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Guest
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"EnigmaPaul at (no spam) gmail.com" <enigmapaul at (no spam) gmail.com> wrote in message
news:9261ecd7-6e78-4e4c-b753-c642d68474f0 at (no spam) g1g2000vbr.googlegroups.com...
[quote]We're having problems with IR remote controls not working in the room
where there are a number of overhead fluorescent lamps. Obviously
interference with the carrier frequency.
Can we install RFI filters on the ballasts to eliminate. Are there
any other solutions?
[/quote]
The IR receiver on your electronic device is being swamped with IR signals
from the cathodes of the fluorescent lamps driven by high-frequency
electronic ballasts. It's a known problem.
Anything you can do that will keep the receiver from "seeing" the ends of
the bare fluorescent lamps will help. I haven't tried it, but a simple
visor at the receiver's sensor ought to result in some improvement.
Changing the ballasts to another kind that operate on a different frequency
would do the job too; but you would have to figure out the frequencies.
I don't see how an RFI filter would do anything. The interference is not
traveling via the power line.
Terry McGowan |
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| TimR... |
| Posted: Sat Oct 24, 2009 5:21 am |
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On Oct 24, 8:05 am, Victor Roberts <x... at (no spam) lighting-research.com> wrote:
[quote]
There is a NEMA white paper that discusses all this. See
NEMA LSD 3-1988 (or a later version) atwww.nema.org.
--
Vic Robertshttp://www.RobertsResearchInc.comhttp://www.cflfacts.com
[/quote]
Thanks for the reference.
I wish I'd had it some years ago. I was staying in a hotel type
facility run by a government agency that shall remained unnamed. They
had just replaced all their incandescent lamps with CFLs, and all
their tv remotes had stopped working.
Somebody had convinced them that the cause was harmonics on the AC
power. So they were in the process of contracting for some very
expensive transformer replacements that surely would have erased any
energy savings from the CFLs. I tried to tell them this didn't make
any sense but they didn't believe me.
I don't know if they ever figured it out, I haven't been back there.
At the time there was a suggestion program where I could get a portion
of the savings back, but there was some bureaucratic reason they
wouldn't accept it from me. |
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| Victor Roberts... |
| Posted: Sat Oct 24, 2009 6:05 am |
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Guest
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On Fri, 23 Oct 2009 09:49:03 -0700 (PDT), TimR
<timothy42b at (no spam) aol.com> wrote:
[quote]On Oct 23, 11:34 am, "TKM" <nom... at (no spam) no.net> wrote:
"EnigmaP... at (no spam) gmail.com" <enigmap... at (no spam) gmail.com> wrote in message
news:9261ecd7-6e78-4e4c-b753-c642d68474f0 at (no spam) g1g2000vbr.googlegroups.com...
We're having problems with IR remote controls not working in the room
where there are a number of overhead fluorescent lamps. Obviously
interference with the carrier frequency.
Can we install RFI filters on the ballasts to eliminate. Are there
any other solutions?
The IR receiver on your electronic device is being swamped with IR signals
from the cathodes of the fluorescent lamps driven by high-frequency
electronic ballasts. It's a known problem.
Anything you can do that will keep the receiver from "seeing" the ends of
the bare fluorescent lamps will help. I haven't tried it, but a simple
visor at the receiver's sensor ought to result in some improvement.
Changing the ballasts to another kind that operate on a different frequency
would do the job too; but you would have to figure out the frequencies.
I don't see how an RFI filter would do anything. The interference is not
traveling via the power line.
Terry McGowan
Yes, exactly.
The lights overload the sensor on the tv set that is supposed to pick
up the signal from the remote.
It happens with CFLs too.
I have seen engineers specify filters and new transformers but of
course it doesn't work. As noted, the interference is light in the
air, not radio waves or electricity. It has nothing to do with
carrier waves, it is just the infrared light from the remote to the
tv.
Last time I was in a motel room where this happened, I put a cardboard
shield over the sensor on the tv. That worked fine.
[/quote]
How old is the TV? For a number of years there has been an
agreement between TV and lamp manufacturers to not use the
same frequency for electronic ballasts that is used for the
TV remote control, but older TV's may still be operating at
a frequency that is now used for electronic ballasts.
There is a NEMA white paper that discusses all this. See
NEMA LSD 3-1988 (or a later version) at www.nema.org.
--
Vic Roberts
http://www.RobertsResearchInc.com
http://www.cflfacts.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission. |
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| Jeff Waymouth... |
| Posted: Sat Oct 24, 2009 8:13 am |
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Guest
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Victor Roberts wrote:
[quote]On Fri, 23 Oct 2009 09:49:03 -0700 (PDT), TimR
timothy42b at (no spam) aol.com> wrote:
On Oct 23, 11:34 am, "TKM" <nom... at (no spam) no.net> wrote:
"EnigmaP... at (no spam) gmail.com" <enigmap... at (no spam) gmail.com> wrote in message
news:9261ecd7-6e78-4e4c-b753-c642d68474f0 at (no spam) g1g2000vbr.googlegroups.com...
We're having problems with IR remote controls not working in the room
where there are a number of overhead fluorescent lamps. Obviously
interference with the carrier frequency.
Can we install RFI filters on the ballasts to eliminate. Are there
any other solutions?
The IR receiver on your electronic device is being swamped with IR signals
from the cathodes of the fluorescent lamps driven by high-frequency
electronic ballasts. It's a known problem.
Anything you can do that will keep the receiver from "seeing" the ends of
the bare fluorescent lamps will help. I haven't tried it, but a simple
visor at the receiver's sensor ought to result in some improvement.
Changing the ballasts to another kind that operate on a different frequency
would do the job too; but you would have to figure out the frequencies.
I don't see how an RFI filter would do anything. The interference is not
traveling via the power line.
Terry McGowan
Yes, exactly.
The lights overload the sensor on the tv set that is supposed to pick
up the signal from the remote.
It happens with CFLs too.
I have seen engineers specify filters and new transformers but of
course it doesn't work. As noted, the interference is light in the
air, not radio waves or electricity. It has nothing to do with
carrier waves, it is just the infrared light from the remote to the
tv.
Last time I was in a motel room where this happened, I put a cardboard
shield over the sensor on the tv. That worked fine.
How old is the TV? For a number of years there has been an
agreement between TV and lamp manufacturers to not use the
same frequency for electronic ballasts that is used for the
TV remote control, but older TV's may still be operating at
a frequency that is now used for electronic ballasts.
There is a NEMA white paper that discusses all this. See
NEMA LSD 3-1988 (or a later version) at www.nema.org.
Two things come to mind.[/quote]
#1 How old are the ballasts which are causing the problem? A while ago
(I think it is at least 5 years now, maybe more) most electronic ballast
manufacturers change output frequency from 25kHz to >40kHz which was
supposed to considerably help this situation. If you can check the
label opn the ballasts themselves, most of them state the output frequency.
#2 Also, when I was in the field, a couple of contractors told me that
when they experienced this issue (especially with TV's in school rooms
after a retrofit)they tried using a single piece of Scotch brand
cellophane tape over the IR receiver on the TV. For some reason
(probably the actual chemical composition of the tape itself) it had to
be Scotch brand. They swore by it and the one time I tried it it
worked. I can't promise anything, because that weas soem time ago, but
hey, it's a quick fix if it works and if it doesn't, a little acetone
should take off any tape residue.
Jeff Waymouth |
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