Transmitting infrared signals
Archiver
Posts: 46,084
I need to send some remote-control commands via an infrared LED and my
BS-2sx. The commands need to go on a 40Khz carrier signal (excuse me
if used wrong terminology). Can a BS-2sx create that carrier on its
own, or does some sort of accessory need to be used (like a 555)?
Thanks
--Alex
BS-2sx. The commands need to go on a 40Khz carrier signal (excuse me
if used wrong terminology). Can a BS-2sx create that carrier on its
own, or does some sort of accessory need to be used (like a 555)?
Thanks
--Alex
Comments
atl_guy1138@y... writes:
> I need to send some remote-control commands via an infrared LED and my
> BS-2sx. The commands need to go on a 40Khz carrier signal (excuse me
> if used wrong terminology). Can a BS-2sx create that carrier on its
> own, or does some sort of accessory need to be used (like a 555)?
>
> Thanks
> --Alex
The Bs2sx can make 40khz, but may not be worth the trouble. If all you want
to do is make 40khz when you push a button and don't need other logic, action
etc, a 555 is about $0.50 and the stamp is well you know a lot more.
The stamp can do 40 khz, it will take a little effort to do the correct amout
of......
Make the output pin high, waste time with some benign instructions for 12.5
micro seconds, make the pin low, waste another 12.5 micro seconds and repeat
the proces. Actually, the time should be slightly less then 12.5 micro
seconds because of the instruction to make the pin go high and make the pin
go low will take some finite amount of time.
I would strongly recommend control the 555 with the stamp. It is easy to set
up the 555 for 40khz (astable mode near 50% duty cycle) and simply enable the
555 with the stamp when you want to drive your IR device......
Questions?????? Don't hesitate to write back.
Ken Mathis
[noparse][[/noparse]Non-text portions of this message have been removed]
> BS-2sx. The commands need to go on a 40Khz carrier signal (excuse me
> if used wrong terminology). Can a BS-2sx create that carrier on its
> own, or does some sort of accessory need to be used (like a 555)?
>
> Thanks
> --Alex
We have an 8-pin IC [noparse][[/noparse]TX-IR] that makes this incredibly simple. It can be used
for
infrared serial communications or as a simple infrared LED modulator with 38KHz
or 40KHz pin-selectable frequencies
http://www.rentron.com/remote_control/TX-IR.htm
The page above includes three pages of schematics in .PDF format showing how to
build infrared transceivers, a simple IR beam detection circuit, and a remote
control
transmitter / receiver.
Regards,
-Bruce
tech@r...
http://www.rentron.com
> In a message dated 1/7/2003 7:58:05 PM Pacific Standard Time,
> atl_guy1138@y... writes:
>
> > I need to send some remote-control commands via an infrared LED
and my
> > BS-2sx. The commands need to go on a 40Khz carrier signal (excuse
me
> > if used wrong terminology). Can a BS-2sx create that carrier on
its
> > own, or does some sort of accessory need to be used (like a 555)?
> >
> > Thanks
> > --Alex
>
> The Bs2sx can make 40khz, but may not be worth the trouble. If all
you want
> to do is make 40khz when you push a button and don't need other
logic, action
> etc, a 555 is about $0.50 and the stamp is well you know a lot more.
>
> The stamp can do 40 khz, it will take a little effort to do the
correct amout
> of......
> Make the output pin high, waste time with some benign instructions
for 12.5
> micro seconds, make the pin low, waste another 12.5 micro seconds
and repeat
> the proces. Actually, the time should be slightly less then 12.5
micro
> seconds because of the instruction to make the pin go high and make
the pin
> go low will take some finite amount of time.
>
> I would strongly recommend control the 555 with the stamp. It is
easy to set
> up the 555 for 40khz (astable mode near 50% duty cycle) and simply
enable the
> 555 with the stamp when you want to drive your IR device......
>
> Questions?????? Don't hesitate to write back.
>
> Ken Mathis
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
Ken,
Thanks for your reply, and I just proved your point about the
overhead involved...a 12-bit command sequence I coded using the
freqout command, which SHOULD have taken a few microseconds, takes
about 5 seconds. I hope the 555 is as easy as you say it is! BTW, I'm
trying to emulate the Sony Control-S infrared protocol to drive a CD
player. It has obviously been done by lots of people (Nirvis.com, for
example). Do you think it would be possible to implement the 555 with
an OOPic as well?
Thanks again,
--Alex
> > I need to send some remote-control commands via an infrared LED
and my
> > BS-2sx. The commands need to go on a 40Khz carrier signal (excuse
me
> > if used wrong terminology). Can a BS-2sx create that carrier on
its
> > own, or does some sort of accessory need to be used (like a 555)?
> >
> > Thanks
> > --Alex
>
> We have an 8-pin IC [noparse][[/noparse]TX-IR] that makes this incredibly simple. It
can be used for
> infrared serial communications or as a simple infrared LED modulator
with 38KHz
> or 40KHz pin-selectable frequencies
http://www.rentron.com/remote_control/TX-IR.htm
>
> The page above includes three pages of schematics in .PDF format
showing how to
> build infrared transceivers, a simple IR beam detection circuit, and
a remote control
> transmitter / receiver.
>
> Regards,
>
> -Bruce
> tech@r...
> http://www.rentron.com
Bruce,
Thanks for the reply. It looks like this IC would indeed make my
40khz carrier signal easy. Now how about the modulation....is that
still up to me and my stamp? Here's an example of what I need to
transmit:
H = 40Khz signal
L = low
2400 microseconds H (init)
600 microseconds L (binary 0)
600 microseconds H (bit delimiter)
1200 microseconds L (binary 1)
600 microseconds H (bit delimiter)
...on for a total of 12 bits
Do I still need to come up with that timing with my microcontroller,
or would the IC help with that?
Thanks again,
--Alex
atl_guy1138@y... writes:
> Ken,
>
> Thanks for your reply, and I just proved your point about the
> overhead involved...a 12-bit command sequence I coded using the
> freqout command, which SHOULD have taken a few microseconds, takes
> about 5 seconds. I hope the 555 is as easy as you say it is! BTW, I'm
> trying to emulate the Sony Control-S infrared protocol to drive a CD
> player. It has obviously been done by lots of people (Nirvis.com, for
> example). Do you think it would be possible to implement the 555 with
> an OOPic as well?
>
> Thanks again,
>
I am not familiar with the OOpic, do you mean a Pic controller? I will also
look at the sight you descibed Nirvis.com and get back to you. If the OOPic
is a Pic controller (similar to an SX), then yes, the 555 can easily be
enabled disabled with a logic 1 and logic 0 respectively. I sent you an email
to your private address requesting a fax number......
Ken Mathis
[noparse][[/noparse]Non-text portions of this message have been removed]
atl_guy1138@y... writes:
> Bruce,
>
> Thanks for the reply. It looks like this IC would indeed make my
> 40khz carrier signal easy. Now how about the modulation....is that
> still up to me and my stamp? Here's an example of what I need to
> transmit:
>
> H = 40Khz signal
> L = low
>
> 2400 microseconds H (init)
> 600 microseconds L (binary 0)
> 600 microseconds H (bit delimiter)
> 1200 microseconds L (binary 1)
> 600 microseconds H (bit delimiter)
> ...on for a total of 12 bits
>
> Do I still need to come up with that timing with my microcontroller,
> or would the IC help with that?
>
> Thanks again,
> --Alex
>
Have you used the SX microcontroller, also sold by Parallax? It will easily
perform the timing you speak of with a great deal of accuracy. Programming
is not nearly as easy as the stamp. However I have delay routines that are
easy to tailor for the desired delay time......
Ken Mathis
[noparse][[/noparse]Non-text portions of this message have been removed]
> 40khz carrier signal easy. Now how about the modulation....is that
> still up to me and my stamp? Here's an example of what I need to
> transmit:
>
> H = 40Khz signal
> L = low
>
> 2400 microseconds H (init)
> 600 microseconds L (binary 0)
> 600 microseconds H (bit delimiter)
> 1200 microseconds L (binary 1)
> 600 microseconds H (bit delimiter)
> ...on for a total of 12 bits
>
> Do I still need to come up with that timing with my microcontroller,
> or would the IC help with that?
>
> Thanks again,
> --Alex
Data present on the DIN pin is recreated on the DOUT pin modulated at
the selected carrier frequency of 38KHz or 40KHz. You still need to
generate the bit timing for your application on the data input pin, but the
TX-IR handles generating the carrier frequency.
Example:
______ ______
DIN_______| |______| |______
______ ______
DOUT_____|||||||||||||||_______|||||||||||||||______
It's much more stable than a 555 timer, requires fewer components, and
much less programming since it handles carrier generation at the band-pass
frequency of the IR detector module.
You just provide the data input.
Regards,
-Bruce
tech@r...
Reynolds Electronics