Hey,
I did the same thing you did. I bought the firecracker kit on x10.com many years ago, and I played around with it a little here and there, but I was either still living at home with my folks or in various apartment buildings where the electrical system was hit or miss. Now that I'm comfortably settled into my own home (woot!) I've given HA a little more attention.
What OS are you running? Any thoughts about setting up a little linux box? I have a main windows desktop that I use mostly for gaming at home, and various mac and windows laptops that I use most of the time, as well as a nokia 770 and a windows mobile phone. All with internet access via the local WLAN. I also set up a linux server mainly for HA but also other stuff for the house like a jukebox and backup server for the laptops.
I find this works very well. I'm a geek so I had the spare PC around and know Linux fairly well. I'm running a 65w PSU in the system, and when idle is pulls about 30W. More than an Elk or something similar, but I can pay a lot of power bills for the cost of an Elk.. especially while I'm still learning what feels right to me.
There is a program called Heyu (heyu.org) that supports the cm17a, firecracker. It's designed to work with the two-way interface for the cm11a, but works fine with the firecracker. Then if you want a two-way you can find the cm11a's on ebay for around $15 shipped. There is another linux app called 'BottleRocket' that is designed just for the firecracker's one-way only interface. Very basic, but fully functional. Since I have so many internet devices running various OSes, I wrote a super simple php based script that sits on my linux server and interfaces to Heyu. it's at
http://www.erasei.com/eckstin/ it's a really dumb (logic-wise) interface, but it works very well with the firecracker.
I've even extended it to support my own custom 'cat alarm system'. I have an eagle-eye motion sensor that watches my kitchen countertops at night and if it sees motion (a cat on the countertop, a big no no) it turns on A2.. which is the vacuum cleaner.. lol. Works like a charm! Via my php script I can arm and disarm the cat alarm from anywhere via my eckstin mobile interface.
I went ahead and got the cm11a and the W800RFa as well, which is a one-way only RECEIVER (the opposite of the firecracker) that can pick up all of the x10 security modules, RFX sensors and a bunch of other stuff as well. It also has crazy range thanks to it's external antennae.
