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From my own experience, the hardest thing in
building your receiver hardware is getting a suitable infra red
receiver IC. Hence, here is a list of IC's that have been
successfully used to build a serial port receiver:
- Siemens SFH 506 (not produced any more, in Germany available
at Schuricht Online)
- Siemens SFH
5110 (successor of SFH 506)
- Radio
Shack 276-0137
- Mitsumi IR Preamp KEY-COOSV (0924G)
- TOSHIBA TK19 444 TFMS 5360
- TEMIC TFMS 5380 by Telefunken Semiconductors
(same pin-out
as SFH 506)
- Sharp IS1U60.
Replace the 5K resistor for a 1.2K (it seems that this IC draws
much more current).
- Everlight IRM-8601S
I heard that Siemens will give you some IC's for free if
you ask them for some 'test samples'. It might be worth a try.
The following text was taken from the lirc-0.3.6
package with kind permission of its author, Ralph Metzler. It
describes how to build a receiver for the serial port. He has also
provided some pictures
of his receiver. Please note that you may have to use different
resistor values than described here depending on your serial port
hardware to make it work. Especially notebook computers have
significantly lower voltages on the serial port and the circuits
described here won't work out of the box. Whenever possible use a
voltage regulator. I received a nice GIF
version of the schematics from Johan Wallin.
One possible receiver hardware only consists of a
diode, 2 resistors, 1 capacitor and a standard infra-red receiver
module (e.g. SFH505 or SFH506-36 from SIEMENS) and has to be
connected to a serial port in the following way:
GND o--------------------------------+------+
| | +-------------------------+
C ----- | | SIEMENS 444 |
e.g. 1N4148 R1 (5K) (10uF) ----- +----+ - SFH 506-36 |
|\ | _____ + | | |
RTS o-| >|--------|_____|------------------------+ + ############## |
|/ | | | ############## |
| | | |
| | R2 (10K) +----+ <- signal |
| | | |
DCD o---------------------------------------+ +-------------------------+
In Germany you can get the SFH 506 e.g. from
ELV-Elektronik for 7.95 DM (approx. $4.30). So, the whole device
(including a 9-pin plug with casing) should not cost much more than
10 DM (< $7).
The SFH 506-30 (Best.-Nr.: 20-164-48) is best for a
30kHz carrier, the SFH 506-36 (Best.-Nr.: 20-169-58) is best for a
36kHz carrier. Since most remotes use a carrier frequency between 35
and 40 kHz, I use the 36kHz version. Only a few use 32 kHz, so 36
kHz is closest to most. According to the data sheet, which you can
find in doc/sfh506.pdf, there are also a few other versions of the
SFH 506. If you know a cheaper source for the SFH 506 or got the
"circuit" to work with a different receiver, please drop me a mail!
I don't want to advertise for SIEMENS or ELV, they
are just the only ones I know about. Several people mailed me that
Radio Shack offers a similar device. Please tell me if and how you
got it to work with lirc. Alternate receiver circuits will be
collected in doc/receivers.
For people concerned about their serial port:
according to the data sheet the SFH 506 only draws about 1mA during
normal operations and the RTS line is also used as a power source by
most mice. R1 keeps the maximum current below 2mA and the SFH 506
from getting a too high operating voltage. You can also use a 78L05
(5V, 100mA) low power voltage regulator to supply the SFH506 with
exactly 5V.
R2 pulls up the DCD line to 10-12V (the logical "0"
of the RS-232C protocol, but DCD=1 !). If your serial port delivers
higher voltages you might want to use a bigger resistor! When an
infra-red signal is received the SFH pulls DCD down to ground, which
should already be interpreted as a logical "1" (DCD=0) by the serial
port. You can probably increase R1 and R2 by a few K Ohm before the
device stops working. I will of course take no responsibility if any
or all parts of your computer go up in smoke.
Here is a small overview of the standard 9-pin and
25-pin Sub-D serial port connectors: 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
Here is the diagram of a receiver circuit using a
Mitsumi receiver module sent to me by Looc ?(have to look up the
last name in another mail I don't have at home right now...)
Here's the schematic of the receiver. It's very
similar to yours... GND o-------------+------------------+------+
| | |
+-----+ | | +-------------------------+
|78L05| C ----- | | MITSUMI |
+-----+ (10uF) ----- +----+ - IR PREAMP |
|\ | | | _____ + | | KEY-COOSV |
RTS o-| >|-------+ +----|_____|------------------+ + |
|/ | | | (printed): |
| | R1 (~1K) | 0924G |
R2 (10K) | | +----+ <- signal |
| | | |
DCD o---------------------------------------+ +-------------------------+
The 78L05 is a low intensity (<100mA) voltage
regulator. I've tried R1=2.1K and it worked. I've written what is
engraved on the detector (and also what is printed, which is
probably some kind of version number, or encoded date).
If you need some more information, please tell me.
Looc
Actually, you can use exactly the same circuit with
a SFH 506
The following was sent to me by Carl van
Schaik.
Just though I would send you [...] a circuit that I
am using for my IR receiver which is giving a very good signal to
noise ratio. (Excuse my poor drawing) GND o--------------------------------+------+
| | +----------------------+
----- | | TOSHIBA TK19 444 |
e.g. 1N4148 (5K) (10uF) ----- +----+ - TFMS 5360 |
|\ | _____ + | | |
RTS o-| >|---+----|_____|------------------------+ + ############## |
|/ | | _____ | ############## |
| _____ / \ | |
+----|_____|---+ |2N2222 | +----+ <- signal |
(10K) | | | _|_ | |
| | C B E | | | +----------------------+
DCD o--------------+ | +-------+ | |(10K)
| | | | | |_|
| +----+ | \ |
| +--|-----+
| _____ /
+----|_____|----+
(100 ohm)
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