This small set of utils allowing to use this strange device: ID 041e:3100 Creative Technology, Ltd [Philips Electronics - RCS Singapore Creative USB IR Receiver] on Linux. The project is simple, small, crude but it works ;).

You can download it here:
creative_rm1500_usb-0.1.tar.gz

Usage instructions.

• hid_read reads from /dev/usb/rm1500 (which should point to valid hiddev device: automagic udev rule is provided) and reports keypresses to stdout.
• event_dispatcher.pl runs hid_read from current directory, reads all his kepreses from stdout, and controls xmms ;)

How does hid_read read the data from remote. This is in source code ;), but to simplify:

//opening device(file)
s = open( "/dev/usb/rm1500", O_RDONLY );

//we want to get info on each report received from device
flags = HIDDEV_FLAG_UREF | HIDDEV_FLAG_REPORT;
ioctl(hid_s, HIDIOCSFLAG, &flags);

//at this point, each read from opened file/device should return
//hiddev_usage_ref structure

struct hiddev_usage_ref uref;
while ( read(hid_s, &uref, sizeof(uref)) >= 0 )
  if ( uref.field_index == HID_FIELD_INDEX_NONE ) {
    //we get this when the new report has been send from device
    //at this point we have the uref structure prefiled with correct report type and id

    //this got guesed by getting the device report descriptor (function devinfo in source)
    uref.field_index = 0; //which field of report
    //this got guesed by taking all values from device and checking which ones are changing ;)
    uref.usage_index = 3; //which usage entry of field

    //fetch the usage code for given indexes
    ioctl(hid_s, HIDIOCGUCODE, &uref, sizeof(uref));
    //fetch the value from report
    ioctl(hid_s, HIDIOCGUSAGE, &uref, sizeof(uref));
    //now we have the key
    cout << "got keycode: " << uref.value << endl;
  }
  // we are not interested in any other events, as they are only giving info what changed in report
  // and this not always works, is complicated, doesn't output anything sensible on repeated key
  // and we already have all the info from real report

Documentation used:

• various resources from http://www.usb.org/developers/hidpage/
• Documentation/usb/hiddev.txt from Linux kernel tree.

Project history/news:

Author: Ecto