<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<HTML>
<HEAD>
<LINK REL=stylesheet TYPE="text/css" HREF="lirc.css">
<LINK REL="shortcut icon" HREF="favicon.ico">
<TITLE>LIRC - Serial Port Receivers</TITLE>
</HEAD>
<BODY BACKGROUND="images/marb18.jpg"
BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#7070E0"
VLINK="#808080" ALINK="#9090FF">
<TABLE WIDTH="100%" BORDER="0" CELLSPACING="0" CELLPADDING="0">
<TR>
<TD WIDTH="100%" HEIGHT="150" BGCOLOR="#000080" ALIGN="RIGHT"
VALIGN="TOP">
<IMG SRC="images/diode.gif" ALT="diode" WIDTH="300"
HEIGHT="150" BORDER="0" HSPACE="20" VSPACE="0" ALIGN="LEFT">
<IMG SRC="images/lirc.gif" ALT="lirc-logo" WIDTH="300"
HEIGHT="150" BORDER="0" HSPACE="20" VSPACE="0" ALIGN="RIGHT">
</TD>
</TR>
<TR>
<TD WIDTH="100%" ALIGN="LEFT" VALIGN="TOP"> <BR>
<!-- Text -->
<CENTER><HR WIDTH="70%">
<H1>Serial Port Receivers</H1>
<HR WIDTH="50%"><BR></CENTER>
<TABLE WIDTH="100%">
<TR>
<TD WIDTH="15%" VALIGN="top">
 
<script type="text/javascript"><!--
google_ad_client = "pub-3628312733106047";
google_ad_width = 120;
google_ad_height = 240;
google_ad_format = "120x240_as";
google_ad_type = "text";
google_ad_channel ="";
google_color_border = "6060C0";
google_color_bg = "FFFFFF";
google_color_link = "7070E0";
google_color_url = "666666";
google_color_text = "333333";
//--></script>
<!-- AD --><script type="text/javascript" src="http://pagead2.googlesyndication.com/pagead/show_ads.js"></script>
</TD>
<TD WIDTH="70%">
<P>
The following page will show you how to build your
own infrared receiver for the serial port. Please
note that the serial port driver in the LIRC package
only supports 8250 compatible UARTs (this includes
the most common 16450 and 16550A types). That means
that it won't work with exotic multi-port cards that
need a special driver. <!-- Alessio Sangalli has put
together an excellent <A HREF="http://www.manoweb.com/alesan/lirc/">step by
step description</A> of how to put together a serial
receiver like described below. Have a look at it. -->
<!-- If you'd rather buy some device than
solder your own circuit I recommend the
receivers from -->
</P>
<P>
From my own experience, the hardest thing in
building your receiver hardware is getting a
suitable infrared receiver IC. Hence, here is a
list of ICs that have been successfully used to
build a serial port receiver. But be aware that not
all of them have the same pin-out!
</P>
<UL>
<LI>
Vishay TSOP 1738 (available in the US at Newark Electronics)<BR>
<!-- AD Available at conrad.de: <IMG SRC="http://banners.webmasterplan.com/view.asp?site=2945&ref=272927&b=0&type=text&tnb=34" BORDER="0" WIDTH="1" HEIGHT="1"><A HREF="http://partners.webmasterplan.com/click.asp?ref=272927&site=2945&type=text&tnb=34&pid=171077" TARGET="_blank">part number 171077</a -->
</LI>
<LI>
Vishay TSOP 1838<BR>
<!-- AD Available at conrad.de: <IMG SRC="http://banners.webmasterplan.com/view.asp?site=2945&ref=272927&b=0&type=text&tnb=34" BORDER="0" WIDTH="1" HEIGHT="1"><A HREF="http://partners.webmasterplan.com/click.asp?ref=272927&site=2945&type=text&tnb=34&pid=171115" TARGET="_blank">part number 171115</a -->
</LI>
<LI>
Vishay <!-- A HREF="http://www.vishay.com/temporary/datasheets/optoelectronics/photomodules/tsop11...html" -->TSOP 11..<!-- /A --> series
</LI>
<LI>
Siemens SFH 506 (not produced any more)
</LI>
<LI>
Siemens <A HREF="http://www.infineon.com/products/opto/pdf/sfh5110.pdf">
SFH 5110 </A> (successor of SFH 506)
</LI>
<LI>
discontinued: Radio Shack 276-0137 (<A HREF="http://sourceforge.net/mailarchive/forum.php?thread_id=590689&forum_id=5339">other
Radio Shack part numbers</A>)
</LI>
<LI>
Radio Shack 276-640<BR>
<FONT COLOR="red">Warning:</FONT> There have been
reports that the signal quality these receivers
produce is very unstable. YMMV. If possible use
another receiver IC.
</LI>
<LI>
Hebei IT <A HREF="http://ledz.com/led.datasheet/PL-IRM0101-3.pdf">PL-IRM0101-3</A>
</LI>
<LI>
Everlight IRM-2238
</LI>
<LI>
Everlight IRM 8100-3-M (Radio Shack part
no. 276-0137B)
</LI>
<LI>
Everlight IRM-8601M
</LI>
<!-- LI>
Panasonic <A HREF="http://www.semicon.panasonic.co.jp/cgi-bin/ds/search.cgi?search_word=PNA46&lang=1">PNA46xxM</A>
</LI -->
<LI>Mitsumi IR Preamp KEY-COOSV (0924G)</LI>
<LI>TOSHIBA TK19 444 TFMS 5360 (known in Italy as Mivar IC)</LI>
<LI>TEMIC TFMS 5380 by Telefunken Semiconductors</LI>
<LI>
Sharp <A HREF="http://www.sharp.co.jp/ecg/opto/products/pdf/ir_devices/ir_ds_ir_durc/is1u60.pdf">
IS1U60</A> (available at <A HREF="http://www.rswww.com">RS</A>, it seems that this
IC draws much more current than the others)<BR>
<FONT COLOR="red">Warning:</FONT> Some users have
reported problems with the IS1U60 receiver. It
picks up ambient light and is nearly unusable with
fluorescent lamps. If ever possible get a
different receiver.
</LI>
<LI>
<A HREF="http://www.everlight.com/">Everlight</A>
<A HREF="http://www.everlight.com/pdf/Irm-8601s.pdf">IRM-8601S</A>
</LI>
<LI>
Sony SBX 1404-01
</LI>
<LI>
Sony SBX 1620-12
</LI>
<LI>
Sharp 1u521X
</LI>
<LI>
Sharp GP1U52XB
</LI>
<LI>
Sharp GP1U271R (available from RS)
</LI>
<LI>
Sharp GP1UD261XK (available from Digikey)
</LI>
<LI>
Panasonic PNA4602M (available from Digikey)
</LI>
<LI>
Panasonic PNA4611M (36 kHz, available from Digikey)
</LI>
<LI>
Panasonic PNA4612M (38 kHz, available from Digikey)
</LI>
<LI>
Kodenshi PIC-12043S
</LI>
<LI>
Daewoo DHR-38 C 28
</LI>
<LI>
ZD1952 (available in Australia at <A HREF="http://www.jaycar.com.au">Jaycar</A>)<BR>
Check the pinout, it's different from most other modules.
</LI>
<LI>
Z1955 (available in Australia at <A HREF="http://www.dse.com.au">Dick Smith Electronics</A>)<BR>
Check the pinout, it's different from most other modules.
</LI>
<LI>
A-Tronic TRM38 IR module
</LI>
<LI>
TRM1038 (manufacturer unknown), <A HREF="pinout_TRM1038.txt">pinout</A>
</LI>
<LI>
Sharp Electronics GP1UD277XK (Digikey part no. 425-1122-ND)<BR>
This is a 56kHz type receiver. It has been reported to also work well with 38kHz remotes.
</LI>
</UL>
<P>
Most of these receivers come in variations
adapted to a specific carrier frequency. You
should choose the 38kHz types because most
remote control standards use this
frequency. 36kHz types should work as well. The
receiver won't stop working if your remote uses
another frequency but the range will
decrease. If in doubt which IR receiver type to
choose you should read this more <A
HREF="cir.html">detailed description on how IR
receivers work</A> internally.
</P>
<P>
There are also some brands that use 56kHz carrier
frequency. A 38kHz receiver should still work to
create a config file for these kinds of remotes at
short range but if you plan to use them regularly
you should use a 56kHz receiver. Bang & Olufsen
uses 455kHz for their remotes so you will need a
matching receiver. 38kHz or 56kHz receivers won't
work.
</P>
<P>
Some HiFi components also have a remote control
output which carries the IR signal at TTL
level. If you plan to integrate your computer
into the HiFi rack, you might be able to reuse
this output instead of using a dedicated
receiver.
</P>
<P>
Additionally to the receiver you will need the
following parts:
</P>
<UL>
<LI>C1 - 4.7µF capacitor</LI>
<LI>D1 - 1N4148 diode</LI>
<LI>R1 - 4k7 resistor (4.7 kOhm)</LI>
<LI>IC2 - 78L05, 100mA, voltage regulator (TO-92 casing)</LI>
<LI>9-pin or 25-pin SUB-D socket</LI>
</UL>
<P>
The pin-out of the voltage regulator usually looks
like this (bottom view):
</P>
<PRE>
1 2 3
_______
/ \ Pin1 = OUT
( o o o ) Pin2 = GND
\ / Pin3 = IN
-___-
</PRE>
<P>
But you should check the data sheet anyway to make
sure you have the same type of regulator that is
used here.
</P>
<P>
Finally we come to the circuit itself. It's rather
simple and can be explained in a few words. Here's
also a <A HREF="images/schematics.gif">nicer
version</A> of the ASCII arts below. There's also a
suggestion how to <A
HREF="images/irrcv_board.gif">layout</A> the circuit
on a 5x5 hole-matrix board. The connector pins on
the data-to-PC are designed to use a standard CD-ROM
audio cables, but of course it's not necessary to
use one.
</P>
<PRE>
IC1 = TSOP 1738
+-----------------------+ 3 R1 (4k7)
| data -> +--------------------------------+------------o DCD
| | _______ |
| ______________ | | 78L05 | | | D1 (1N4148)
| / | +-----+-----|OUT IN|--+ | |
| ( | 2 | | + |__GND__| | | | /|
| \______________ + +----+ ----- | +----+------|< |--o RTS
| | ----- | IC2 | \|
| | 1 | |
| - +----------+---------+------------------------o GND
+-----------------------+ C1 (4.7µF)
</PRE>
<P>
The power for the circuit comes from the RTS line of
the serial port. D1 protects the circuit from the
negative voltage that is usually on the RTS pin. The
LIRC driver will change the serial port settings on
initialization so that the circuit will get the
necessary positive voltage. For most standard PC
serial ports this will be approximately 10V. IC2
will convert the input voltage to exactly 5V. As the
input voltage for the 78Lxx type regulators has to
be at least 2V higher than the output voltage to
work reliably, this circuit probably won't work on
some notebooks. The line drivers inside notebooks
often provide voltages about 6V or even less. So you
should make sure that your serial port delivers at
least 8V of output voltage. If your serial port
provides less you can also try using a low-drop
voltage regulator (e.g. LP 2950 CZ) instead of the
regulator suggested here. Low-drop types need much
less voltage offset for reliable regulation. Instead
of pulling the power supply from the serial port you
can also use a different source like e.g. the USB
port or the internal 5V line to power the
circuit. Then you won't need a voltage regulator at
all.
</P>
<P>
C1 is optional but I recommend using it anyway. R1
is a pull-up that makes sure the DCD line is on a
valid voltage level if the receiver does not receive
anything. When an infrared signal is detected IC1
(this is true for active low receivers, if you use
an active high receiver leave away R1 or make it a
pull-down to GND) pulls DCD down to ground, which
should already be interpreted as a logical "1"
(DCD=0) by the serial port.
</P>
<P>
It should be noted that the circuit described above
does not fully comply to the RS232 standard as
latter demands a voltage swing of at least -3V/3V
for the signals. This circuit will provide
approximately 0V/5V which the majority of serial
ports will also accept. If you have problems with
this circuit or want to use it on a serial port that
does not provide enough voltage for the regulator,
you should use the <A HREF="http://www.tb-electronic.de/vdr/lirc/lirc_rx.html">more
advanced circuit</A> (<A HREF="PCB.pdf">PCB layout</A>) suggested by Thomas Breuer in
this <A HREF="http://sourceforge.net/mailarchive/message.php?msg_id=2593921">mailing
list post</A>. This circuit addresses both
problems but will need some additional parts.
</P>
<P>
Here is a small overview of the most important pins
of standard 9-pin and 25-pin SUB-D serial port
connectors:
</P>
<P>
<PRE>
Name 25-pin 9-pin
---------------------------------------------------------
TxD 2 3 transmit data
RxD 3 2 receive data
RTS 4 7 request to send (here: power source)
CTS 5 8 clear to send
DSR 6 6 data set ready
GND 7 5 ground
DCD 8 1 data carrier detect (here: signal line)
DTR 20 4 data terminal ready
</PRE>
<P>
The following <A HREF="pictures1.html">pictures</A>
were taken from the
<A HREF="http://www.metzlerbros.de/lirc/index.html">
lirc-0.3.6</A> package with kind permission of its
author, Ralph Metzler. They show the receiver
build into a SUB-D hood. The original circuit used
resistors to get the 5V voltage but as this caused
problems for many people it shouldn't be used
anymore.
</P>
<P>
Andreas Nestler came up with a nice idea for a
receiver casing. He assembled the infrared receiver
inside an old <A
HREF="pictures2.html">mouse</A>. Note that he had to
replace the old mouse plug because not all the
necessary signals were passed through.
</P>
<P>
Here's a highlight for all Star Wars fans: Petri
Damstén built his receiver inside a <A
HREF="http://www.iki.fi/damu/mods/tie_lirc/index.html">TIE
fighter</A> model.
</P>
</TD>
<TD WIDTH="15%">
 
</TD>
</TR>
</TABLE>
<!-- Text -->
<BR> <BR>
<CENTER>[<A HREF="index.html">LIRC Homepage</A>]</CENTER>
<BR> <BR>
</TD>
</TR>
<TR>
<TD WIDTH="100%" BGCOLOR="#000080" ALIGN="LEFT" VALIGN="TOP">
 <BR>
</TD>
</TR>
</TABLE>
</BODY>
</HTML>
