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Mon, 07 Aug 2006

X10 Home Automation Using a CM11A Deivce on FreeBSD
A little over three years ago, I bought an X10 CM11A Serial Inferface Controller. Then using some very handy Perl modules I wrote a small piece of software that completely controls the outdoor lighting for my home. The lights come on at sunset and are all off by sunrise. It's a great little system and pretty easy to implement (on FreeBSD).

I chose the X10 CM11A Serial Interface Controller because there is a Perl module (ControlX10::CM11) explicitly written for the hardware. Because the CM11A connects to my computer via the serial port, ControlX10::CM11 is dependent on the Device::SerialPort Perl module. Consider the following sample code:

#!/usr/bin/perl

use Device::SerialPort;
$serial_port = Device::SerialPort->new('/dev/cuaa0',1);
die "Can't open serial port $serial_port: $^E\n" unless ($serial_port);

$serial_port->error_msg(1); # use built-in error messages
$serial_port->user_msg(0);
$serial_port->databits(8);
$serial_port->baudrate(4800);
$serial_port->parity("none");
$serial_port->stopbits(1);
$serial_port->dtr_active(1);
$serial_port->handshake("none");
$serial_port->write_settings || die "Could not set up port\n";

use ControlX10::CM11;
receive_cm11($serial_port);
send_cm11($serial_port, 'A1');
send_cm11($serial_port, 'A1');
send_cm11($serial_port, 'AJ'); # J is on; K is off
send_cm11($serial_port, 'OJ'); # J is on; K is off

When executed, this code will send an X10 signal that will turn on any X10 modules with an address of 'A1'. Not very interesting since there isn't any code logic to determine when the "on" signal should be sent. In order to determine when I should send "on" and "off" signals to my different X10 lighting modules, I use the Astro::Sunrise Perl module. It is a handy little module that will quickly determine the sunrise and sunset time for a latitude and longitude on any given day. Here is small snippet of code that generates sunrise and sunset times for my general location:

#!/usr/bin/perl

require Astro::Sunrise;

$long = -122;
$lat = 47.5;

$date = localtime(time);
print "$date\n";
$sunrise = Astro::Sunrise::sun_rise($long, $lat);
print "sunrise at $sunrise\n";
$sunset = Astro::Sunrise::sun_set($long, $lat);
print "sunset at $sunset\n";

Nice and simple and easy.

For my home automation software, I turn on all of the lights at sunset. Then I have different sets of lights turn off at specific times as the night progresses. Furthermore, I wanted to add a bit of randomness to the off events so that it didn't just look like the lights were going off at the same exact time every night. The lights that I choose to stay on all night are turned off at sunrise (or more specifically 1 hour before sunrise).

Here is the code that runs my home lighting; I call it from cron every minute of the day. Have fun with it!

(Update Thu Aug 10 00:08:53 PDT 2006 // fixed some punctation mistakes)

:: Posted by rus on Mon, 07 Aug 2006 8:23 pm
:: Filed under /contrib/x10



        

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