IR transmitter/reciever viewing angles question.

[Rusty Magic]

Hi all,

I need to find out what kind of viewing angles are common in IR
emmitters/recievers. I check the Radio Shack ones, and it seems to be
45 degrees. 12.5 degrees on either side of centreline. Is this the
biggest possible? Or are ones that transmit 90 degrees manufactured?

Thanks.

 

[Gary Reichlinger]

On 12 May 2004 14:26:03 -0700, rustimagik@yahoo.com (Rusty Magic)
wrote:

I need to find out what kind of viewing angles are common in IR
emmitters/recievers. I check the Radio Shack ones, and it seems to be
45 degrees. 12.5 degrees on either side of centreline. Is this the
biggest possible? Or are ones that transmit 90 degrees manufactured?

The IRDA standard is 30 degrees. This would be for most
transceivers designed for laptops, PDAs, cell phones, etc. The
viewing angle is deliberately limited in order to avoid interference
between multiple users.

 

[Watson A.Name \"Watt Sun]

Rusty Magic wrote:

Hi all,

I need to find out what kind of viewing angles are common in IR
emmitters/recievers. I check the Radio Shack ones, and it seems to be
45 degrees. 12.5 degrees on either side of centreline. Is this the
biggest possible? Or are ones that transmit 90 degrees manufactured?

Thanks.

Methinks you meant 22.5 degrees on either side. The wider the beam, the
lower the 'brightness' so it's self-defeating if you want the beam to
function at a distance. The best thing to do to siden the beam is to
reflect it off a curved first surface mirror to spread it out. The
curve will be convex.

 

[Watson A.Name \"Watt Sun]

Rusty Magic wrote:

Hi all,

I need to find out what kind of viewing angles are common in IR
emmitters/recievers. I check the Radio Shack ones, and it seems to be
45 degrees. 12.5 degrees on either side of centreline. Is this the
biggest possible? Or are ones that transmit 90 degrees manufactured?

Thanks.

Methinks you meant 22.5 degrees on either side. The wider the beam, the
lower the 'brightness' so it's self-defeating if you want the beam to
function at a distance. The best thing to do to widen the beam is to
reflect it off a curved first surface mirror to spread it out. The
curve will be convex.

 

"Watson A.Name \"Watt Sun - the Dark Remover\""

The wider the beam, the
lower the 'brightness' so it's self-defeating if you want the beam to
function at a distance.

Indeed. We got some amazing distances when modulating one of those
(visible red) laser diode modules with an IR remote, but the beam
width was pretty small... 8*)

--
William Smith
ComputerSmiths Consulting, Inc. www.compusmiths.com

 

[Rusty Magic]

Thanks for the info.
I got my numbers mixed up, I meant 22.5 degrees on either side of
centre. Anyway..

Darn, I was hoping to have 6 emitters on 6 sides of a small cube (say,
a die), and if each covered 90 degrees (without a cone restricting the
angle, as in remote control units for tv's and vcr's), the room could
be covered. With the same setup with recievers, with a circuit board
and chip determining which emitter recieves the emission.
30 degrees just won't cut it.

Thanks again.

Gary Reichlinger <reichln@navix.net> wrote in message news:<6a75a0dt53qab0dnp4qsdu1rn8fr8mkqmp@4ax.com>...

On 12 May 2004 14:26:03 -0700, rustimagik@yahoo.com (Rusty Magic)
wrote:

I need to find out what kind of viewing angles are common in IR
emmitters/recievers. I check the Radio Shack ones, and it seems to be
45 degrees. 12.5 degrees on either side of centreline. Is this the
biggest possible? Or are ones that transmit 90 degrees manufactured?

The IRDA standard is 30 degrees. This would be for most
transceivers designed for laptops, PDAs, cell phones, etc. The
viewing angle is deliberately limited in order to avoid interference
between multiple users.