Programming Jabber

The setup_RCX() function

This function is called once every time the script is started and is required to initialize the RCX:

sub setup_RCX {
  my $sensor = shift;
  my $rcx = Win32::OLE->new('SPIRIT.SpiritCtrl.1');
  $Win32::OLE::Warn = 0;
  $rcx->{ComPortNo} = 1;
  $rcx->{InitComm};
  $rcx->SetSensorType($sensor, 3);
  $rcx->SetSensorMode($sensor, 2);
  return $rcx;
}

A Win32::OLE object representing the RCX’s ActiveX control Spirit is instantiated. A Win32::OLE function is used to suppress warnings, and the RCX is initialized by setting the COM port to COM1 for serial communications. The sensor type and mode are set for the light sensor attached to the connector identified by the value passed into the $sensor variable. Table 9-2 shows us that sensor type 3 represents Light, and sensor mode 2 specifies a Transitional measurement mode, the upshot of which is that the values returned on a poll are all within a certain restricted range, which makes it easier to decide whether there’s any coffee in the pot.

We return the Win32::OLE RCX object to be used elsewhere in the script for calibration and polling.