Re: IR Transmitter (irsend just takes voltage on DTR from -12 to -11V)

[Anshuman T. <pa...@ho...>]

Thanks Chris. I think that is what is happening. After sending this out I 
just thought
about it and was thinking about using a scope instead. I do have an visible 
LED but
no current seems to be flowing ... I guess I need to do more debug.. maybe 
one of
the transistors are not working properly.

Thanks a lot!



>From: Chris Morgan <cm...@al...>
>To: "Anshuman Thakur" <pa...@ho...>, lir...@li...
>Subject: Re: IR Transmitter (irsend just takes voltage on DTR from -12 to 
>-11V)
>Date: Wed, 15 Oct 2003 22:09:15 -0400
>
>I'll reply to the mailing list for the record.
>
>I suspect that everything is working properly, as you mentioned in your 
>last
>email when writing a large file to the serial port you see DTR go from -10V
>to +10V or something in that range, when you stop the transfer it should
>return back to -10V.  If this is in fact what you are seeing then it is
>likely that DTR is working just fine and that your serial port is setup and
>lircd is also working correctly.
>
>It also isn't all that unreasonable to think that you couldn't "see" any
>change to DTR when running irsend if you are using a multimeter.  The
>transmission should result in DTR being pulled high a number of times but
>with very little time between each pulse.  Due to the signal oscillating 
>and
>the short duration of each pulse will only result in a minor voltage change
>when measured via a multimeter.  I just metered my ir transmitter, should 
>be
>the same one from Enrique Vidal, and saw ~-10.53V when off and ~-10.48V 
>when
>transmitting and then back to ~-10.53V.
>
>You also didn't mention whether you had wired up the optional LED to the
>circuit.  I would recommend you wire up the led, this will provide visual
>feedback when you transmit that you can't really get with a multimeter.
>
>Thanks,
>Chris
>
>
>On Wednesday 15 October 2003 04:43 pm, Anshuman Thakur wrote:
> > The last post got garbled. So trying again.
> >
> > The problem that I am seeing is that the DTR only move from -12V to -11V 
>(1
> > volt delta)
> > when I do an irsend.
> >
> > I am attaching output of lsmod. (If you see anything wrong there). Also
> > attaching some debug
> > message from /var/log/messages
> >
> > Oct 14 22:38:19 localhost kernel: lirc_serial: auto-detected active high
> > receiver
> >
> > Oct 14 22:39:53 localhost kernel: lirc_serial: Interrupt 4, port 03f8
> > obtained
> > Oct 14 22:39:53 localhost kernel: lirc_serial: in
> > calc_pulse_lengths_in_clocks, freq=38000, duty_cycle=50,
> > clk/jiffy=21954560, pulse=28887, space=28888, conv_us_to_clocks=2195
> > Oct 14 22:39:53 localhost kernel: lirc_serial: after SET_SEND_CARRIER,
> > freq=38000 pulse=28887, space=28888, conv_us_to_clocks=2195
> > Oct 14 22:39:53 localhost kernel: lirc_serial: in
> > calc_pulse_lengths_in_clocks, freq=38000, duty_cycle=50,
> > clk/jiffy=21954560, pulse=28887, space=28888, conv_us_to_clocks=2195
> > Oct 14 22:39:53 localhost kernel: lirc_serial: after 
>SET_SEND_DUTY_CYCLE,
> > freq=38000 pulse=28887, space=28888, conv_us_to_clocks=2195
> > Oct 14 22:39:53 localhost kernel: lirc_serial: in
> > calc_pulse_lengths_in_clocks, freq=38000, duty_cycle=50,
> > clk/jiffy=21954560, pulse=28887
> >
> > ........
> >
> > Output of lsmod
> >
> > Module                  Size  Used by    Not tainted
> > snd-pcm-oss            45284   0  (autoclean)
> > ide-cd                 35712   0  (autoclean)
> > cdrom                  33728   0  (autoclean) [ide-cd]
> > snd-via82xx            16608   0  (autoclean)
> > snd-mixer-oss          16408   0  (autoclean) [snd-pcm-oss]
> > snd-ymfpci             49760   0  (autoclean)
> > snd-pcm                85312   0  (autoclean) [snd-pcm-oss snd-via82xx
> > snd-ymfpci]
> > snd-page-alloc          9844   0  (autoclean) [snd-via82xx snd-ymfpci
> > snd-pcm]
> > gameport                3380   0  (autoclean) [snd-ymfpci]
> > snd-opl3-lib            8708   0  (autoclean) [snd-ymfpci]
> > snd-timer              19556   0  (autoclean) [snd-pcm snd-opl3-lib]
> > snd-hwdep               6944   0  (autoclean) [snd-opl3-lib]
> > snd-mpu401-uart         5200   0  (autoclean) [snd-via82xx snd-ymfpci]
> > snd-rawmidi            18592   0  (autoclean) [snd-mpu401-uart]
> > snd-seq-device          6204   0  (autoclean) [snd-opl3-lib snd-rawmidi]
> > snd-ac97-codec         50200   0  (autoclean) [snd-via82xx snd-ymfpci]
> > snd                    43076   0  (autoclean) [snd-pcm-oss snd-via82xx
> > snd-mixer-oss snd-ymfpci snd-pcm snd-opl3-lib snd-timer snd-hwdep
> > snd-mpu401-uart snd-rawmidi snd-seq-device snd-ac97-codec]
> > lirc_serial            10368   0
> > parport_pc             19076   1  (autoclean)
> > lp                      9028   0  (autoclean)
> > parport                37056   1  (autoclean) [parport_pc lp]
> > tuner                  12544   1  (autoclean)
> > bttv                   82528   0  (autoclean)
> > i2c-algo-bit            9000   0  (autoclean) [bttv]
> > soundcore               6436   8  (autoclean) [snd bttv]
> > i2c-core               21124   0  (autoclean) [tuner bttv i2c-algo-bit]
> > videodev                8288   3  (autoclean) [bttv]
> > autofs                 13364   0  (autoclean) (unused)
> > via-rhine              16496   1
> > mii                     3992   0  [via-rhine]
> > ipt_REJECT              3992   6  (autoclean)
> > iptable_filter          2444   1  (autoclean)
> > ip_tables              15096   2  [ipt_REJECT iptable_filter]
> > serial                 55300   1  (autoclean)
> > microcode               4668   0  (autoclean)
> > keybdev                 2976   0  (unused)
> > mousedev                5556   1
> > hid                    22276   0  (unused)
> > input                   5888   0  [keybdev mousedev hid]
> > usb-uhci               26412   0  (unused)
> > ehci-hcd               20104   0  (unused)
> > usbcore                79360   1  [hid usb-uhci ehci-hcd]
> > ext3                   70976   2
> > jbd                    51924   2  [ext3]
> >
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