loop.pl

   1 #!/usr/bin/perl
   2 use strict;
   3
   4 use v5.10.1;
   5
   6 use Mojolicious::Lite;
   7 use Serial;
   8 use Mojo::IOLoop;
   9 use Mojo::IOLoop::Stream;
  10 use Mojo::Transaction::WebSocket;
  11 #use Mojo::JSON  qw(decode_json encode_json);
  12 use JSON;
  13 use Debug;
  14 use SMGLog;
  15 use Math::Round qw(nearest);
  16 use File::Copy;
  17 use Data::Random qw(rand_chars);
  18 use IO::File;
  19
  20 use constant pi => 3.14159265358979;
  21
  22 my $devname = "/dev/davis";
  23 my $datafn = ".loop_data";
  24 my $dataf;
  25
  26 my $poll_interval = 2.5;
  27 my $rain_mult = 0.2;                            # 0.1 or 0.2 mm or 0.01 inches
  28 my $tid;
  29 my $rid;
  30 our $did;
  31 my $nlcount;
  32 my $state = "ready";
  33 my $buf;
  34 my $dbg;
  35 my $ser;                                                        # the serial port Mojo::IOLoop::Stream
  36 my $last_min_h;
  37 my $last_hour_h;
  38
  39 our $json = JSON->new->canonical(1);
  40 our $WS = {};                                   # websocket connections
  41
  42 our $ld = {};
  43
  44 our $loop_count;                                # how many LOOPs we have done, used as start indicator
  45
  46 our     @crc_table = (
  47                                   0x0, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
  48                                   0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
  49                                   0x1231, 0x210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
  50                                   0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
  51                                   0x2462, 0x3443, 0x420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
  52                                   0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
  53                                   0x3653, 0x2672, 0x1611, 0x630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
  54                                   0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
  55                                   0x48c4, 0x58e5, 0x6886, 0x78a7, 0x840, 0x1861, 0x2802, 0x3823,
  56                                   0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
  57                                   0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0xa50, 0x3a33, 0x2a12,
  58                                   0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
  59                                   0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0xc60, 0x1c41,
  60                                   0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
  61                                   0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0xe70,
  62                                   0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
  63                                   0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
  64                                   0x1080, 0xa1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
  65                                   0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
  66                                   0x2b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
  67                                   0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
  68                                   0x34e2, 0x24c3, 0x14a0, 0x481, 0x7466, 0x6447, 0x5424, 0x4405,
  69                                   0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
  70                                   0x26d3, 0x36f2, 0x691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
  71                                   0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
  72                                   0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x8e1, 0x3882, 0x28a3,
  73                                   0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
  74                                   0x4a75, 0x5a54, 0x6a37, 0x7a16, 0xaf1, 0x1ad0, 0x2ab3, 0x3a92,
  75                                   0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
  76                                   0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0xcc1,
  77                                   0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
  78                                   0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0xed1, 0x1ef0
  79                                  );
  80
  81 our %bar_trend;
  82
  83 $bar_trend{-60} = "Falling Rapidly";
  84 $bar_trend{196} = "Falling Rapidly";
  85 $bar_trend{-20} = "Falling Slowly";
  86 $bar_trend{236} = "Falling Slowly";
  87 $bar_trend{0} = "Steady";
  88 $bar_trend{20} = "Rising Slowly";
  89 $bar_trend{60} = "Rising Rapidly";
  90
  91 our $ending = 0;
  92
  93 $SIG{TERM} = $SIG{INT} = sub {++$ending; Mojo::IOLoop->stop;};
  94 $SIG{HUP} = 'IGNORE';
  95
  96
  97 # WebSocket weather service
  98 websocket '/weather' => sub {
  99   my $c = shift;
 100   my $msg = shift;
 101   my $tx = $c->tx;
 102
 103   # Opened
 104   app->log->debug('WebSocket opened.');
 105   dbg 'WebSocket opened' if isdbg 'chan';
 106   $WS->{$tx} = $tx;
 107
 108   # send historical data
 109   $c->send($ld->{lasthour_h}) if exists $ld->{lasthour_h};
 110   $c->send($ld->{lastmin_h}) if exists $ld->{lastmin_h};
 111
 112   # send the last 24 hour's worth of data to the graph
 113   my $lg = SMGLog->new('day');
 114   my $tnow = time;
 115   my $dayno = int($tnow/86400);
 116   send_history($c, $lg, $tnow, $_) for ($dayno-1, $dayno);
 117
 118   # disable timeout
 119   $c->inactivity_timeout(3615);
 120
 121   # Incoming message
 122   $c->on(
 123                  message => sub {
 124                          my ($c, $msg) = @_;
 125                          dbg "websocket: text $msg" if isdbg 'chan';
 126                  },
 127                  json => sub {
 128                          my ($c, $msg) = @_;
 129                          dbg "websocket: json $msg" if isdbg 'chan';
 130                  }
 131   );
 132
 133   # Closed
 134   $c->on(finish => sub {
 135     my ($c, $code, $reason) = @_;
 136     app->log->debug("WebSocket closed with status $code.");
 137         dbg "websocket closed with status $code" if isdbg 'chan';
 138         delete $WS->{$tx};
 139   });
 140 };
 141
 142 get '/' => {template => 'index'};
 143
 144
 145 dbginit();
 146 if (@ARGV) {
 147         dbgadd(@ARGV);
 148 }
 149 dbgadd('chan');
 150
 151 dbg '***';
 152 dbg "*** starting $0";
 153 dbg '***';
 154
 155 read_ld();
 156
 157 our $dlog = SMGLog->new("day");
 158 dbg "before next tick";
 159 Mojo::IOLoop->next_tick(sub { loop() });
 160 dbg "before app start";
 161 app->start;
 162 dbg "after app start";
 163
 164 write_ld();
 165 $dataf->close if $dataf;
 166 undef $dataf;
 167
 168
 169 # move all the files along one
 170 cycle_loop_data_files();
 171
 172 dbg '***';
 173 dbg "*** ending $0";
 174 dbg '***';
 175
 176 exit 0;
 177
 178 ##################################################################################
 179
 180 sub loop
 181 {
 182         dbg "last_min: " . scalar gmtime($ld->{last_min});
 183         dbg "last_hour: " . scalar gmtime($ld->{last_hour});
 184
 185         $did = Mojo::IOLoop->recurring(1 => sub {$dlog->flushall});
 186
 187         do_reopen($devname);
 188 }
 189
 190
 191
 192 sub on_read
 193 {
 194         my ($ser, $d) = @_;
 195         $buf .= $d;
 196         $d =~ s/([\%\x00-\x1f\x7f-\xff])/sprintf("%%%02X", ord($1))/eg;
 197         dbg "read added '$d' buf lth=" . length $buf if isdbg 'raw';
 198         if ($state eq 'waitnl' && $buf =~ /[\cJ\cM]+/) {
 199                 dbg "Got \\n" if isdbg 'state';
 200                 Mojo::IOLoop->remove($tid) if $tid;
 201                 undef $tid;
 202                 undef $buf;
 203                 $nlcount = 0;
 204                 $ser->write("LPS 1 1\n");
 205                 chgstate("waitloop");
 206         } elsif ($state eq "waitloop") {
 207                 if ($buf =~ /\x06/) {
 208                         dbg "Got ACK 0x06" if isdbg 'state';
 209                         chgstate('waitlooprec');
 210                         undef $buf;
 211                 }
 212         } elsif ($state eq 'waitlooprec') {
 213                 if (length $buf >= 99) {
 214                         dbg "got loop record" if isdbg 'chan';
 215                         chgstate('');
 216                         process($buf);
 217                         undef $buf;
 218                 }
 219         }
 220 }
 221
 222 sub start_loop
 223 {
 224         $nlcount = 1;
 225         dbg "start_loop writing $nlcount \\n" if isdbg 'state';
 226         $ser->write("\n");
 227         Mojo::IOLoop->remove($tid) if $tid;
 228         undef $tid;
 229         $tid = Mojo::IOLoop->recurring(0.6 => sub {
 230                                                                            if (++$nlcount > 10) {
 231                                                                                    dbg "\\n count > 10, closing connection" if isdbg 'chan';
 232                                                                                    do_reopen($devname);
 233                                                                                    return;
 234                                                                            }
 235                                                                            dbg "writing $nlcount \\n" if isdbg 'state';
 236                                                                            $ser->write("\n");
 237                                                                    });
 238         chgstate("waitnl");
 239 }
 240
 241 sub chgstate
 242 {
 243         dbg "state '$state' -> '$_[0]'" if isdbg 'state';
 244         $state = $_[0];
 245 }
 246
 247 sub do_reopen
 248 {
 249         my $name = shift;
 250         dbg "do reopen on '$name' ending $ending";
 251         unless ($ending) {
 252                 $ser = do_open($name);
 253                 start_loop();
 254                 chgstate('');
 255                 $nlcount = 0;
 256                 Mojo::IOLoop->start unless Mojo::IOLoop->is_running;
 257         }
 258 }
 259
 260 sub do_open
 261 {
 262         my $name = shift;
 263
 264         $ser->close if $ser;
 265         undef $ser;
 266
 267         my $ob = Serial->new($name, 19200) || die "$name $!\n";
 268         dbg "streaming $name fileno(" . fileno($ob) . ")" if isdbg 'chan';
 269
 270         my $ser = Mojo::IOLoop::Stream->new($ob);
 271         $ser->on(error=>sub {dbg "serial $_[1]"; do_reopen($name) unless $ending});
 272         $ser->on(close=>sub {dbg "serial closing"; do_reopen($name) unless $ending});
 273         $ser->on(timeout=>sub {dbg "serial timeout";});
 274         $ser->on(read=>sub {on_read(@_)});
 275         $ser->start;
 276
 277         Mojo::IOLoop->remove($tid) if $tid;
 278         undef $tid;
 279         Mojo::IOLoop->remove($rid) if $rid;
 280         undef $rid;
 281         $rid = Mojo::IOLoop->recurring($poll_interval => sub {
 282                                                                            start_loop() if !$state;
 283                                                                    });
 284         chgstate('');
 285         $nlcount = 0;
 286
 287         return $ser;
 288 }
 289
 290 my @min;
 291 my @hour;
 292
 293 sub process
 294 {
 295         my $blk = shift;
 296         my $loo =  substr $blk,0,3;
 297         unless ( $loo eq 'LOO') {
 298                 dbg "Block invalid loo -> $loo" if isdbg 'chan'; return;
 299         }
 300
 301         my $tmp;
 302         my $temp;
 303         my $rain;
 304         my %h;
 305
 306         my $crc_calc = CRC_CCITT($blk);
 307
 308         if ($crc_calc==0) {
 309
 310                 # Common ones
 311                 $tmp = unpack("s", substr $blk,7,2) / 1000;
 312                 $h{Pressure} = nearest(1, in2mb($tmp));
 313
 314                 $tmp = unpack("s", substr $blk,9,2) / 10;
 315                 $h{Temp_In} = nearest(0.1, f2c($tmp));
 316
 317                 $temp  = nearest(0.1, f2c(unpack("s", substr $blk,12,2) / 10));
 318                 $h{Temp_Out}  = $temp;
 319                 if ($temp > 75 || $temp < -75) {
 320                         dbg "LOOP Temperature out of range ($temp), record ignored";
 321                         return;
 322                 }
 323
 324                 $tmp = unpack("C", substr $blk,14,1);
 325                 $h{Wind} = nearest(0.1, mph2mps($tmp));
 326                 $h{Dir}     = unpack("s", substr $blk,16,2)+0;
 327
 328                 my $wind = {w => $h{Wind}, d => $h{Dir}};
 329                 $wind = 0 if $wind == 255;
 330                 push @{$ld->{wind_min}}, $wind;
 331
 332                 $tmp = int(unpack("C", substr $blk,33,1)+0);
 333                 if ($tmp > 100) {
 334                         dbg "LOOP Outside Humidity out of range ($tmp), record ignored";
 335                         return;
 336                 }
 337                 $h{Humidity_Out} = $tmp;
 338                 $tmp = int(unpack("C", substr $blk,11,1)+0);
 339                 if ($tmp > 100) {
 340                         dbg "LOOP Inside Humidity out of range ($tmp), record ignored";
 341                         return;
 342                 }
 343                 $h{Humidity_In}  = $tmp;
 344
 345
 346                 $tmp = unpack("C", substr $blk,43,1)+0;
 347                 $h{UV} = $tmp unless $tmp >= 255;
 348                 $tmp = unpack("s", substr $blk,44,2)+0; # watt/m**2
 349                 $h{Solar} = $tmp unless $tmp >= 32767;
 350
 351                 #       $h{Rain_Rate}  = nearest(0.1,unpack("s", substr $blk,41,2) * $rain_mult);
 352                 $rain = $h{Rain_Day}   = nearest(0.1, unpack("s", substr $blk,50,2) * $rain_mult);
 353                 my $delta_rain = $h{Rain} = nearest(0.1, ($rain >= $ld->{last_rain} ? $rain - $ld->{last_rain} : $rain)) if $loop_count;
 354                 $ld->{last_rain} = $rain;
 355
 356                 # what sort of packet is it?
 357                 my $sort =  unpack("C", substr $blk,4,1);
 358                 if ($sort) {
 359
 360                         # Newer LOOP2 packet
 361                         $tmp = unpack("C", substr $blk,18,2);
 362                         #               $h{Wind_Avg_10} = nearest(0.1,mph2mps($tmp/10));
 363                         $tmp = unpack("C", substr $blk,20,2);
 364                         #               $h{Wind_Avg_2} = nearest(0.1,mph2mps($tmp/10));
 365                         $tmp = unpack("C", substr $blk,22,2);
 366                         #               $h{Wind_Gust_10} = nearest(0.1,mph2mps($tmp/10));
 367
 368                         #               $h{Dir_Avg_10} = unpack("C", substr $blk,24,2)+0;
 369                         $tmp = unpack("C", substr $blk,30,2);
 370                         $h{Dew_Point} = nearest(0.1, f2c($tmp));
 371
 372                 } else {
 373
 374                         # Older LOOP packet
 375                         $tmp = unpack("C", substr $blk,15,1);
 376                         #               $h{Wind_Avg_10} = nearest(0.1,mph2mps($tmp));
 377                         $h{Dew_Point}  = nearest(0.1, dew_point($h{Temp_Out}, $h{Humidity_Out}));
 378                         $h{Rain_Month}  = nearest(0.1, unpack("s", substr $blk,52,2) * $rain_mult);
 379                         $h{Rain_Year}  = nearest(0.1, unpack("s", substr $blk,54,2) * $rain_mult);
 380                 }
 381
 382                 my $ts = time;
 383                 my $s;
 384                 my $dayno = int($ts/86400);
 385                 if ($dayno > $ld->{last_day}) {
 386                         $ld->{Temp_Out_Max} = $ld->{Temp_Out_Min} = $temp;
 387                         $ld->{Temp_Out_Max_T} = $ld->{Temp_Out_Min_T} = clocktime($ts, 0);
 388                         $ld->{last_day} = $dayno;
 389                         write_ld();
 390                         cycle_loop_data_files();
 391                 }
 392                 if ($temp > $ld->{Temp_Out_Max}) {
 393                         $ld->{Temp_Out_Max} = $temp;
 394                         $ld->{Temp_Out_Max_T} = clocktime($ts, 0);
 395                         write_ld();
 396                 }
 397                 if ($temp < $ld->{Temp_Out_Min}) {
 398                         $ld->{Temp_Out_Min} = $temp;
 399                         $ld->{Temp_Out_Min_T} = clocktime($ts, 0);
 400                         write_ld();
 401                 }
 402
 403                 if ($ts >= $ld->{last_hour} + 1800) {
 404                         $h{Pressure_Trend}    = unpack("C", substr $blk,3,1);
 405                         $h{Pressure_Trend_txt} = $bar_trend{$h{Pressure_Trend}};
 406                         $h{Batt_TX_OK}  = (unpack("C", substr $blk,86,1)+0) ^ 1;
 407                         $h{Batt_Console}  = nearest(0.01, unpack("s", substr $blk,87,2) * 0.005859375);
 408                         $h{Forecast_Icon}  = unpack("C", substr $blk,89,1);
 409                         $h{Forecast_Rule}  = unpack("C", substr $blk,90,1);
 410                         $h{Sunrise}  = sprintf( "%04d", unpack("S", substr $blk,91,2) );
 411                         $h{Sunrise}  =~ s/(\d{2})(\d{2})/$1:$2/;
 412                         $h{Sunset}   = sprintf( "%04d", unpack("S", substr $blk,93,2) );
 413                         $h{Sunset}  =~ s/(\d{2})(\d{2})/$1:$2/;
 414                         $h{Temp_Out_Max} = $ld->{Temp_Out_Max};
 415                         $h{Temp_Out_Min} = $ld->{Temp_Out_Min};
 416                         $h{Temp_Out_Max_T} = $ld->{Temp_Out_Max_T};
 417                         $h{Temp_Out_Min_T} = $ld->{Temp_Out_Min_T};
 418
 419
 420                         if ($loop_count) {      # i.e not the first
 421                                 my $a = wind_average(scalar @{$ld->{wind_hour}} ? @{$ld->{wind_hour}} : {w => $h{Wind}, d => $h{Dir}});
 422
 423                                 $h{Wind_1h} = nearest(0.1, $a->{w});
 424                                 $h{Dir_1h} = nearest(0.1, $a->{d});
 425
 426                                 $a = wind_average(@{$ld->{wind_min}});
 427                                 $h{Wind_1m} = nearest(0.1, $a->{w});
 428                                 $h{Dir_1m} = nearest(1, $a->{d});
 429
 430                                 ($h{Rain_1m}, $h{Rain_1h}, $h{Rain_24h}) = calc_rain($rain);
 431                         }
 432                         $ld->{last_rain_min} = $ld->{last_rain_hour} = $rain;
 433
 434                         $last_hour_h = {%h};
 435                         $s = genstr($ts, 'h', \%h);
 436                         $ld->{lasthour_h} = $s;
 437
 438                         $ld->{last_hour} = int($ts/1800)*1800;
 439                         $ld->{last_min} = int($ts/60)*60;
 440                         @{$ld->{wind_hour}} = ();
 441                         @{$ld->{wind_min}} = ();
 442
 443                         output_str($s, 1) if $s;
 444                         write_ld();
 445
 446                 } elsif ($ts >= $ld->{last_min} + 60) {
 447                         my $a = wind_average(@{$ld->{wind_min}});
 448                         my %save;
 449
 450                         push @{$ld->{wind_hour}}, $a;
 451
 452                         if ($loop_count) {      # i.e not the first
 453                                 my $rm;
 454
 455                                 $h{Wind_1m} = nearest(0.1, $a->{w});
 456                                 $h{Dir_1m} = nearest(1, $a->{d});
 457                                 ($h{Rain_1m}, $h{Rain_1h}, $h{Rain_24h}) = calc_rain($rain);
 458                         }
 459                         $ld->{last_rain_min} = $rain;
 460
 461                         $h{Temp_Out_Max} = $ld->{Temp_Out_Max};
 462                         $h{Temp_Out_Min} = $ld->{Temp_Out_Min};
 463                         $h{Temp_Out_Max_T} = $ld->{Temp_Out_Max_T};
 464                         $h{Temp_Out_Min_T} = $ld->{Temp_Out_Min_T};
 465
 466                         $last_min_h = {%h};
 467                         $s = genstr($ts, 'm', \%h);
 468                         $ld->{lastmin_h} = $s;
 469
 470                         $ld->{last_min} = int($ts/60)*60;
 471                         @{$ld->{wind_min}} = ();
 472
 473                         output_str($s, 1) if $s;
 474                         write_ld();
 475
 476                 } else {
 477                         my $o = gen_hash_diff($ld->{last_h}, \%h);
 478                         if ($o) {
 479                                 $s = genstr($ts, 'r', $o);
 480                         }
 481                         else {
 482                                 dbg "loop rec not changed" if isdbg 'chan';
 483                         }
 484                         output_str($s, 0) if $s;
 485                 }
 486                 $ld->{last_h} = \%h;
 487                 ++$loop_count;
 488         } else {
 489                 dbg "CRC check failed for LOOP data!";
 490         }
 491         return;
 492 }
 493
 494 sub genstr
 495 {
 496         my $ts = shift;
 497         my $let = shift;
 498         my $h = shift;
 499
 500         my $j =  $json->encode($h);
 501         my $tm = clocktime($ts, $let eq 'r' ? 1 : 0);
 502         return qq|{"tm":"$tm","t":$ts,"$let":$j}|;
 503 }
 504
 505 sub clocktime
 506 {
 507         my $ts = shift;
 508         my $secsreq = shift;
 509         my ($sec,$min,$hr) = (gmtime $ts)[0,1,2];
 510         my $s;
 511         if ($secsreq) {
 512                 $s = sprintf "%02d:%02d:%02d", $hr, $min, $sec;
 513         } else {
 514                 $s = sprintf "%02d:%02d", $hr, $min;
 515         }
 516         return $s;
 517 }
 518
 519 sub output_str
 520 {
 521         my $s = shift;
 522         my $logit = shift;
 523
 524         dbg $s;
 525 #       say $s;
 526         $dlog->writenow($s) if $logit;
 527         foreach my $ws (keys $WS) {
 528                 my $tx = $WS->{$ws};
 529                 if ($tx) {
 530                         $tx->send($s);
 531                 } else {
 532                         delete $WS->{$tx};
 533                 }
 534         }
 535 }
 536
 537 sub gen_hash_diff
 538 {
 539         my $last = shift;
 540         my $now = shift;
 541         my %o;
 542         my $count;
 543
 544         while (my ($k, $v) = each %$now) {
 545                 if (!exists $last->{$k} || $last->{$k} ne $now->{$k}) {
 546                         $o{$k} = $v;
 547                         ++$count;
 548                 }
 549         }
 550         return $count ? \%o : undef;
 551 }
 552
 553 sub dew_point
 554 {
 555         my $temp = shift @_;
 556         my $rh   = shift @_;
 557
 558         #  Using the simplified approximation for dew point
 559         #  Accurate to 1 degree C for humidities > 50 %
 560         #  http://en.wikipedia.org/wiki/Dew_point
 561
 562         my $dewpoint = $temp - ((100 - $rh) / 5);
 563
 564         # this is the more complete one (which doesn't work)
 565         #my $a = 6.1121;
 566         #my $b = 18.678;
 567         #my $c = 257.14;
 568         #my $ytrh = log(($rh/100) + ($b * $temp) / ($c + $temp));
 569         #my $dewpoint = ($c * $ytrh) / ($b - $ytrh);
 570
 571         return $dewpoint;
 572 }
 573
 574 sub CRC_CCITT
 575 {
 576     # Expects packed data...
 577     my $data_str = shift @_;
 578
 579         my $crc = 0;
 580         my @lst = split //, $data_str;
 581         foreach my $data (@lst) {
 582                 my $data = unpack("c",$data);
 583
 584                 my $crc_prev = $crc;
 585                 my $index = $crc >> 8 ^ $data;
 586                 my $lhs = $crc_table[$index];
 587                 #print "lhs=$lhs, crc=$crc\n";
 588                 my $rhs = ($crc << 8) & 0xFFFF;
 589                 $crc = $lhs ^ $rhs;
 590
 591
 592         }
 593
 594         return $crc;
 595 }
 596
 597 sub f2c
 598 {
 599         return ($_[0] - 32) * 5/9;
 600 }
 601
 602 sub mph2mps
 603 {
 604         return $_[0] * 0.44704;
 605 }
 606
 607 sub in2mb
 608 {
 609         return $_[0] * 33.8637526;
 610 }
 611
 612 sub wind_average
 613 {
 614         my ($sindir, $cosdir, $wind);
 615         my $count;
 616
 617         foreach my $r (@_) {
 618                 $wind += $r->{w};
 619                 $sindir += sin(d2r($r->{d})) * $r->{w};
 620                 $cosdir += cos(d2r($r->{d})) * $r->{w};
 621                 ++$count;
 622         }
 623
 624         my $avhdg = r2d(atan2($sindir, $cosdir));
 625         $avhdg += 360 if $avhdg < 0;
 626         return {w => nearest(0.1,$wind / $count), d => nearest(0.1,$avhdg)};
 627 }
 628
 629 # radians to degrees
 630 sub r2d
 631 {
 632     my $n = shift;
 633     return ($n / pi) * 180;
 634 }
 635
 636 # degrees to radians
 637 sub d2r
 638 {
 639     my $n = shift;
 640     return ($n / 180) * pi;
 641 }
 642
 643 sub calc_rain
 644 {
 645         my $rain = shift;
 646
 647         $ld->{rain24} ||= [];
 648
 649         my $Rain_1h = nearest(0.1, $rain >= $ld->{last_rain_hour} ? $rain - $ld->{last_rain_hour} : $rain); # this is the rate for this hour, so far
 650         my $rm = nearest(0.1, $rain >= $ld->{last_rain_min} ? $rain - $ld->{last_rain_min} : $rain);
 651         my $Rain_1m = nearest(0.1, $rm);
 652         push @{$ld->{rain24}}, $Rain_1m;
 653         $ld->{rain_24} += $rm;
 654         while (@{$ld->{rain24}} > 24*60) {
 655                 $ld->{rain_24} -= shift @{$ld->{rain24}};
 656         }
 657         my $Rain_24h = nearest(0.1, $ld->{rain_24});
 658         return ($Rain_1m, $Rain_1h, $Rain_24h);
 659 }
 660
 661 sub read_ld
 662 {
 663         unless ($dataf) {
 664                 $dataf = IO::File->new("+>> $datafn") or die "cannot open $datafn $!";
 665                 $dataf->autoflush(1);
 666         }
 667
 668         seek $dataf, 0, 0;
 669         my $s = <$dataf>;
 670         chomp $s;
 671         dbg "read loop data: $s" if isdbg 'json';
 672         $ld = $json->decode($s) if length $s;
 673
 674         # sort out rain stats
 675         my $c;
 676         if ($ld->{rain24} && ($c = @{$ld->{rain24}}) < 24*60) {
 677                 my $diff = 24*60 - $c;
 678                 unshift @{$ld->{rain24}}, 0 for 0 .. $diff;
 679         }
 680         my $rain;
 681
 682         if ($ld->{rain24}) {
 683                 $rain += $_ for @{$ld->{rain24}};
 684         }
 685
 686         $ld->{rain_24} = nearest(0.1, $rain);
 687         delete $ld->{hour};
 688         delete $ld->{min};
 689 }
 690
 691 sub write_ld
 692 {
 693         unless ($dataf) {
 694                 $dataf = IO::File->new("+>> $datafn") or die "cannot open $datafn $!";
 695                 $dataf->autoflush(1);
 696         }
 697
 698         seek $dataf, 0, 0;
 699         truncate $dataf, 0;
 700         $ld->{ts} = time;
 701         my $s = $json->encode($ld);
 702         dbg "write loop data: $s" if isdbg 'json';
 703         print $dataf "$s\n";
 704 }
 705
 706 sub cycle_loop_data_files
 707 {
 708         $dataf->close if $dataf;
 709         undef $dataf;
 710
 711         rename "$datafn.oooo", "$datafn.ooooo";
 712         rename "$datafn.ooo", "$datafn.oooo";
 713         rename "$datafn.oo", "$datafn.ooo";
 714         rename "$datafn.o", "$datafn.oo";
 715         copy $datafn, "$datafn.o";
 716 }
 717
 718 sub send_history
 719 {
 720         my $c = shift;
 721         my $lg = shift;
 722         my $tnow = shift;
 723         my $dayno = shift;
 724         if ($lg->open($dayno, 'r+')) {
 725                 while (my $l = $lg->read) {
 726                         next unless $l =~ /,"h":/;
 727                         my ($t) = $l =~ /"t":(\d+)/;
 728                         if ($t && $t >= $tnow-86400) {
 729                                 $c->send($l);
 730 #                               dbg "sending: $l";
 731                         }
 732                 }
 733                 $lg->close;
 734         }
 735 }