X-Git-Url: http://git.rot13.org/?p=air-quality;a=blobdiff_plain;f=zph02.pl;h=42336609b724bc830e428b33c8d60234d6403d33;hp=50aadcb21475dcec9e28420cc17ff95f018da059;hb=a18f9c9581e10c5c0f5b27bb6a8f9da2079093d6;hpb=390a683649fd1e1a505e3f4ee55fb9048e3e5f56

diff --git a/zph02.pl b/zph02.pl
index 50aadcb..4233660 100755
--- a/zph02.pl
+++ b/zph02.pl
@@ -24,9 +24,19 @@ while (1) {
 	my ($len, $string) = $s->read(9);
 	if ( $len > 0 ) {
 		my @v = unpack('C*', $string);
-		warn "# $len ",dump($string), dump( @v ), $/;
+		#warn "# $len ",dump($string), dump( @v ), $/;
+
+		my $sum = 0;
+		# -2 is specified in datasheet, next byte is 0 so it's same as -1
+		foreach my $i ( 0 .. $#v - 2 ) {
+			$sum += $v[$i];
+			$sum = $sum & 0xff;
+		}
+		$sum = ~$sum & 0xff;
+
+		my $checksum = $v[8];
 		my $pcnt = $v[3] + ( $v[4] / 100 );
-		if ( $v[0] == 0xff ) {
+		if ( $v[0] == 0xff && $sum == $checksum ) {
 			my $influx = "zph02,dc=trnjanska pm25_pcnt=$pcnt";
 			print "$influx\n";
 			system "curl --silent -XPOST '$influx_url' --data-binary '$influx'"