For example:

+———————+——-+——+
| time | power | temp |
+———————+——-+——+
| 2009-11-06 23:19:24 | 1493 | 22.9 |
| 2009-11-06 23:19:30 | 1492 | 22.9 |
| 2009-11-06 23:19:36 | 1512 | 22.9 |
| 2009-11-06 23:19:42 | 1514 | 22.9 |
| 2009-11-06 23:19:49 | 1506 | 22.9 |
| 2009-11-06 23:19:54 | 1498 | 22.9 |
| 2009-11-06 23:20:00 | 1491 | 22.9 |
| 2009-11-06 23:20:07 | 1487 | 22.9 |
| 2009-11-06 23:20:13 | 1486 | 22.9 |
| 2009-11-06 23:20:19 | 1488 | 22.9 |
+———————+——-+——+
10 rows in set (0.00 sec)

Then I can pull out data like this:

select time ,truncate(avg(power),1) as power, truncate(avg(temp),1) as temp from power where time > SUBDATE(NOW(), INTERVAL 1 WEEK) group by floor(unix_timestamp(time)/3600);
+———————+——–+——+
| time | power | temp |
+———————+——–+——+
| 2009-11-12 10:59:18 | 960.8 | 22.8 |
| 2009-11-12 11:00:00 | 980.7 | 22.7 |
| 2009-11-12 12:00:02 | 991.5 | 22.7 |
…..
| 2009-11-19 08:00:00 | 996.5 | 23.2 |
| 2009-11-19 09:00:05 | 973.0 | 22.9 |
| 2009-11-19 10:00:05 | 974.7 | 22.8 |
+———————+——–+——+

You can convert your YYYYMMDDhhmmss to mysql time with something like:

select str_to_date(‘20080502231747′, ‘%Y%m%d%H%i%s’);
+———————————————–+
| str_to_date(‘20080502231747′, ‘%Y%m%d%H%i%s’) |
+———————————————–+
| 2008-05-02 23:17:47 |
+———————————————–+

so you could convert that to unixtime.

#!/usr/bin/perl
# Based on logger.pl by Bruce S. Garlock 2002-09-11
# (see http://aplawrence.com/Unix/logger.html)
# Requirements: Device::SerialPort 0.12 (from cpan)

use Device::SerialPort 0.12;

$LOGDIR = “~/log”; # path to data file
$LOGFILE = “currentcost.log”; # file name to output to
$PORT = “/dev/ttyS0″; # port to watch

# Serial Settings
$ob = Device::SerialPort->new ($PORT) || die “Can’t Open $PORT: $!”;
$ob->baudrate(2400) || die “failed setting baudrate”; # set to 9600 if you have the newer version
$ob->parity(“none”) || die “failed setting parity”;
$ob->databits(8) || die “failed setting databits”;
$ob->handshake(“none”) || die “failed setting handshake”;
$ob->write_settings || die “no settings”;

# open the logfile, and Port
open(LOG,”>>${LOGDIR}/${LOGFILE}”) || die “can’t open smdr file $LOGDIR/$LOGFILE for append: $SUB $!\n”;
open(DEV, “<$PORT”) || die “Cannot open $PORT: $_”;

select(LOG), $| = 1; # set nonbufferd mode

# Loop forver, logging data to the log file
while($_ = ){ # print input device to file
print LOG $_;
print STDOUT $_; # optional logging to STDOUT
}
undef $ob;

After hooking up my Current Cost Meter to a database recently I’ve been logging my power usage so the next step is to look at what I can do with the data. As I mentioned when I introduced my meter lo……