Detection seems to work

diff --git a/CurrentCost-detect.pl b/CurrentCost-detect.pl
new file mode 100755 (executable)
index 0000000..9f004a4
--- /dev/null
+++ b/CurrentCost-detect.pl
@@ -0,0 +1,76 @@
+#!/usr/bin/perl -w
+
+# Reads data from a Current Cost device via serial port.
+# Run me from /etc/crontab with a line like:
+#     @reboot root /usr/local/rrd/CurrentCost.pl
+
+use strict;
+use Device::SerialPort qw( :PARAM :STAT 0.07 );
+use Fcntl;
+
+#die "port not specified" unless defined $PORT and -c $PORT;
+# TODO: If multiple ttyUSBs around, autodetect which is which...
+
+my $BAUD = "57600";
+my $SERIALBUFSIZE = 200;
+my @ports = `ls /dev/ttyUSB*`;
+
+my $arg = shift @ARGV;
+my $dbg = (defined $arg && ($arg eq "--debug"));
+
+my ($PORT,$FOUND);
+
+for $PORT (@ports) {
+
+       chomp $PORT;
+       my $ob = Device::SerialPort->new($PORT);
+       unless (-c $PORT && defined($ob)) {
+               warn "cannot set up for port $PORT!";
+               next;
+       }
+
+       $ob->baudrate($BAUD);
+       $ob->write_settings;
+       # TODO check for locks;
+       # Lock ports in turn;
+       # Trap to unlock
+
+       print "Trying $PORT\n" if $dbg;
+
+       unless (sysopen(SERIAL, "$PORT", O_NONBLOCK|O_RDWR)) {
+               warn "opening serial $PORT: $!";
+               next;
+       };
+
+       # wait for up to 10s to read from the port.
+       my $bits = '';
+       vec($bits, fileno(SERIAL), 1) = 1;
+    my $got = select($bits, undef, $bits, 10);
+
+       select(undef,undef,undef,1); # let the data come in, hope there's a big UART
+
+       if ($got) {
+               my $line;
+               for (my $i=0; $i<4; $i++) {
+                       my $n = sysread (SERIAL, $line, $SERIALBUFSIZE);
+                       print "read from $PORT: $line\n" if $dbg;
+
+                       if ($line =~ m!<tmpr> *([\-\d.]+)</tmpr>.*<ch1><watts>0*(\d+)</watts></ch1>!) {
+                               print "Found a CurrentCost on $PORT!\n" if $dbg;
+                               $FOUND= $PORT;
+                               last;
+                       }
+               }
+       }
+
+       $ob->close or warn "closing $PORT failed: $!";
+       close SERIAL or warn "closing $PORT: $!";
+
+       last if defined $FOUND;
+}
+
+die "No working devices" unless defined $FOUND;
+
+print "OK, using $FOUND\n" if $dbg;
+system("/usr/local/rrd/CurrentCost.pl $FOUND");
+