1 files changed, 48 insertions, 0 deletions
diff --git a/tools/beacon/decode.pl b/tools/beacon/decode.pl
new file mode 100755
index 0000000..28bf82b
--- /dev/null
+++ b/tools/beacon/decode.pl
@@ -0,0 +1,48 @@
+#!/usr/bin/perl -w
+
+use strict;
+use MIME::Base32 qw( RFC ); 
+
+my @beacons;
+if(!$ARGV[0] || $ARGV[0] eq "-") {
+  @beacons = <STDIN>;
+} else {
+  open(my $fh, "<", $ARGV[0]) or die "Unable to open file " . $ARGV[0];
+  @beacons = <$fh>;  
+  close($fh)
+}
+
+foreach(@beacons) { 
+  my $beacon = $_;
+  $beacon =~ s/\s*$//g; 
+  $beacon =~ s/^\s*//g; 
+
+  if($beacon =~ /([^ ]+) ([A-Z2-7]{3}) ([A-Z2-7])/) {
+    my $preamble = $1;
+    my $cnt = $2;
+    my $checksum = $3;
+
+    my $cntval = unpack("n", MIME::Base32::decode($cnt . "=")) >> 1;
+    my $csval_recv = unpack("C", MIME::Base32::decode($checksum . "=")) >> 3;
+
+    my $csval_calc = ord('N') - ord(' ');
+    my @values = unpack("C*", $preamble);
+    @values = (@values, unpack("C*", $cnt));
+    foreach(@values) { $csval_calc ^= $_ - ord(' '); }
+    $csval_calc = ($csval_calc & 0x1F) ^ (($csval_calc & 0x20) >> 5);
+   
+    print $beacon . " ->  cnt: " . $cntval;
+    if($csval_calc != $csval_recv) {
+      print "  checksom wrong! (" . sprintf("%02X", $csval_recv) . " vs. " . sprintf("%02X", $csval_calc) . ")\n";
+    } else {
+      print "  checksom ok! (" . sprintf("%02X", $csval_recv) . ")\n";
+    }
+
+
+  } else {
+    print $beacon . " -> Beacon format error!\n";
+  }
+
+
+}
+