From a18f9c9581e10c5c0f5b27bb6a8f9da2079093d6 Mon Sep 17 00:00:00 2001 From: Dobrica Pavlinusic Date: Sun, 29 Sep 2019 17:02:50 +0200 Subject: [PATCH] check checksum before sending data to influx --- zph02.pl | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) 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'" -- 2.20.1