Trouble w/ Radio Shack 276-0137 IR Detector

[Cameron B. P. <ca...@ak...>]

Hello,

I have been trying for the past day or so to get LIRC working with a
homebrew serial receiver. I live in the US so getting the Radio Shack part
was easy, but getting it to work is not.

I built the circuit on a breadboard from this link:

http://skyscraper.fortunecity.com/andreessen/769/

I removed the 9-pin female end of a modem cable and used my ohm-meter to
find pins 1 , 5, 7 and connected them to the breadboard. The circuit is very
easy and I had no problem at all.

I then downloaded the tar.gz version of lirc and attempted to install. I am
running a fresh copy of Redhat 7.0 and I hadn't yet compiled a new kernel.

I got the error in the FAQ about not have a kernel configured for module
support. I compiled and installed a 2.2.18 kernel and tried lirc again. This
time the module wouldn't make. So I ditched the tarball and got CVS. This
worked... I got a lirc_serial module. woo hoo...

I plugged in the ir receiver I had made on COM2 and loaded up mode2. I
anxiously grabbed up any remote I could find a started hitting buttons. No
activity...

I unplugged and then plugged in the cable. This produced some activity in
mode2. I did it again and it displayed more data. So I took this to mean I
had the right serial port selected and lirc was working, but for some reason
my circuit was not.

I took the circuit loose and examined it. All connections seemed right. I
tried it again and again and even swapped to com1 and recompiled.

I played with it for several hours and used my ohm meter to test the voltage
on the IR detector.

The Vcc is setting at 2.77 volts to ground. The Vout is at 0.1 volts to
ground. I checked the voltage between Vcc and Gnd and it shows 7.22 volts.

The recommended voltage on the IR detector is 4.3 to 5.7 volts. So it seems
to me the values of the resistors are not correct.

I also thought I may have had a bad detector that was shorting the circuit
and dragging the Vcc down. I went back down to radio shack and picked up a
new set of parts. I built the circuit again and had exactly the same
results.

I am going to play with the values of the resistors and see what I can come
up with.


I wonder if anyone else on the list has ran into this and how they may have
come to get it working.


Thanks,

Cameron