IguanaWorks USB IR transceiver

19.08.2012 22:16

I bookmarked this little gadget a while ago. Having recently solved my problems with scriptable switching of PulseAudio audio outputs I thought it's time to finally order it and try to automate a few other home-theater related operations through it. Over the summer a few other infrared-communication related things also piled up on my desk, so having an universal IR transmitter and receiver within reach seemed like a good idea.

IguanaWorks USB IR transceiver

This is an IguanaWorks USB IR transceiver, the hybrid version. Hybrid meaning it has both an integrated IR LED and detector pair and a 3.5 mm jack for an external transmitter.

From the software side it comes with quite an elaborate framework, free and open source of course. Software also comes in the form of Debian binary and source packages, which is a nice plus. I did have a small problem compiling them though since the build process seems to depend on the iguanair user being present on the system. This user only gets created during installation which makes it kind of a catch-22 situation. Once compiled the packages did work fine on my Debian Squeeze system.

After everything is installed, you get:

  • igdaemon, a daemon that communicates with the actual USB dongle,
  • igclient, a client that exposes daemon functionality through a command-line interface,
  • a patched version of lircd daemon that includes a driver that offloads communication to igdaemon.

lirc is the usual Linux framework for dealing with infrared remotes. It knows how to inject keypresses into the Linux input system when an IR command is received and comes with utilities that can send commands back through the IR transmitter to other devices. This is the first time I'm dealing with it and I'm still a bit confused how it all fits together, but right now it appears some parts of the lirc ecosystem don't currently work with iguanair at all. For instance, xmode2 utility that shows received IR signals in an oscilloscope-like display isn't supported.

As I'm currently mostly interested in using this from my scripts, using igclient directly seems to be simplest option. There are also Python bindings for the client library, but they appear undocumented and I haven't yet took a dive into the source code to figure it out.

The client reports the received signals in the form of space-pulse durations, like this:

$ igclient --receiver-on --sleep 10
received 1 signal(s):
  space: 95573
received 3 signal(s):
  space: 7616
  pulse: 64
  space: 65536

I'm not yet sure what the units for those numbers are. According to the documentation the transmit functionality expects a similarly formatted input, but I have yet to try it out. It seems that if I want to plot the signals on a time line I will have to write my own utility for that.

To be honest I expected using this to be simpler from the computer side. In the end it basically has the same functionality as my 433 MHz receiver. One thing I also overlooked is that it's only capable of transmitting modulated on-off keyed transmissions (25 - 125 kHz carrier), which makes it useless for devices that don't use that, like shutter glasses. But given that I did basically zero research before ordering it I can't really blame anyone else but me for that (and that bookmark must have been at least a year old). Just yesterday I also stumbled on IR toy which appears to be a similar device. It would be interesting to know how it compares with the IguanaWorks one.

Posted by Tomaž | Categories: Digital

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