ir detection

Posted by Al on July 10, 2005, 2:59 am

Can reliability of IR or RF signals be influenced by time of day? I have
an IR transmitter
attached to my PC. It sends a signal to an extender, which converts it,
sends it to an RF convertor
in another room, and the convertor then sends the IR signal to the TV set.
Since I am just testing now, its just a simple on/off command.

This morning, I was able to put the last convertor almost 10 feet away from
the TV
set and it worked fine. This evening, it has to be within four feet to
work.

I am using the MyExtender control from MyTv. I am open to other
suggestions.

Thanks in advance for any responses.

Posted by Peter Baltus on July 10, 2005, 3:05 am

> Can reliability of IR or RF signals be influenced by time of day? I have

Hi Al,

could it be that e.g. the ambient light on the IR receiver changes depending
on the
time of day? Depending on the design of the IR receiver, this could change
the sensitivity. In a similar way, there might be equipment that is switched
on only at certain times during the day, e.g. fluorescent lights, microwave
ovens, etc. Such equipment might interfere with the RF transmission,
depending on frequency, distance, etc.

I'd suggest trying to eliminate influences one at a time, e.g. first finding
out whether it is RF or IR that is affected, then eliminating possible
interferers/fixing ambient lighting, etc. Good luck & please let us know
what came out!

Peter

Posted by Mark Haase on July 11, 2005, 12:34 am

wrote:

> Can reliability of IR or RF signals be influenced by time of day? I have
> an IR transmitter
> attached to my PC. It sends a signal to an extender, which converts it,
> sends it to an RF convertor
> in another room, and the convertor then sends the IR signal to the TV set.
> Since I am just testing now, its just a simple on/off command.
>
> This morning, I was able to put the last convertor almost 10 feet away from
> the TV
> set and it worked fine. This evening, it has to be within four feet to
> work.
>
> I am using the MyExtender control from MyTv. I am open to other
> suggestions.
>
> Thanks in advance for any responses.

Most IR products use modulated light, I think at 38khz standard. So they
should be resistant to interference. I know nothing about RF
transmission, but if the last convertor needs to be moved closer, then
its probably a problem on the IR end. I'm not familiar with the product
you mention, but is it battery operated? IR LEDS consume a lot of power
and could drain batteries real quickly.

--
|\/| /| |2 |<
mehaase(at)sas(dot)upenn(dot)edu

Posted by RedX on July 11, 2005, 4:05 am

> wrote:

> > Can reliability of IR or RF signals be influenced by time of day? I

have

> > an IR transmitter
> > attached to my PC. It sends a signal to an extender, which converts it,
> > sends it to an RF convertor
> > in another room, and the convertor then sends the IR signal to the TV

set.

> > Since I am just testing now, its just a simple on/off command.
> > This morning, I was able to put the last convertor almost 10 feet away

from

> > the TV
> > set and it worked fine. This evening, it has to be within four feet to
> > work.
> > I am using the MyExtender control from MyTv. I am open to other
> > suggestions.
> > Thanks in advance for any responses.

> Most IR products use modulated light, I think at 38khz standard. So they
> should be resistant to interference. I know nothing about RF
> transmission, but if the last convertor needs to be moved closer, then
> its probably a problem on the IR end. I'm not familiar with the product
> you mention, but is it battery operated? IR LEDS consume a lot of power
> and could drain batteries real quickly.
> --
> |\/| /| |2 |<
> mehaase(at)sas(dot)upenn(dot)edu

Modulated IR signals are resistant to ambient light within reasonable
limits. Sunlight can block IR receivers. Try closing the curtains. Is it
aimed directly at the receiver? IR is a line-of-sight transmission, so both
the transmitter as the receiver should be able to "see" each other. A
powerfull remote control can under some conditions reach a receiver
indirectly (by reflection) but this is very unreliable.
Otherwise replace the batteries. The range of a remote control depends
mostly on the health of the batteries.

--Patrik

Posted by Dennis Clark on July 14, 2005, 12:20 pm

: Can reliability of IR or RF signals be influenced by time of day? I have
: an IR transmitter
: attached to my PC. It sends a signal to an extender, which converts it,
: sends it to an RF convertor
: in another room, and the convertor then sends the IR signal to the TV set.
: Since I am just testing now, its just a simple on/off command.

Absolutely. While the IR signal is modulated to reduce interference
from ambient light, remember that the Sun transmits on all frequencies
and modulations randomly. This means that your effective range of any
IR transmitter will be heavily influenced by ambient solar radiation.
You'll get lots better range at night than when you are getting solar
rays blasting in the window.

DLC

: This morning, I was able to put the last convertor almost 10 feet away from
: the TV
: set and it worked fine. This evening, it has to be within four feet to
: work.

: I am using the MyExtender control from MyTv. I am open to other
: suggestions.

: Thanks in advance for any responses.

--
============================================================================
* Dennis Clark dlc@frii.com www.techtoystoday.com *
* "Programming and Customizing the OOPic Microcontroller" Mcgraw-Hill 2003 *
============================================================================

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