Hey Gill thanks for some great alternative ideas. That's what I was seeking. I have currently alot of custom control circuitry, mostly 12 & 24 VDC relays that I originally located in the Jbox of each light. Originally used SPST, and switching to SPDT w/2 120VAC sources - photo controlled on NO and relay controlled area source on NC allowing all lights in a group or area to be turned on simultaneously. The SPDT relays need an additional "hot" to each fixture/relay location so it was more efficient to centralize my relays and reroute the "hot" for each lite to the central location. Doing this opened the door to all sorts of options so I created an overall project plan under which this project is just one in a series. Otherwise I would never complete anything.
Funny you mention the old pc system. I do/did have a 286 that used to run the basic system. I had standalone Z80 boards supervising real time I/O that had RS232 ports hooked to a 4 port digiboard on the 286. I wrote a custom menu interface with Turbo Basic that supervised a mess of IO routines, a mix of 8086 ASM, .COM files supplied with the digiboard, and creative use of DOS interrupts and batch files. I had an internal Hayes 2400 (smoking hot at the time) and ran Procomm scripts for remote control which was later upgraded to PC Anywhere. Ahhhh, those were the fun days .... errrr well maybe I should re-think that - adding 256K of RAM by piggyback soldering 36 ram chips and a decoder IC wasn't so easy. Might take a year & a megawatt to upgrade to 1 Gb of RAM.
But as you can tell I am an old DOS and discrete component guy and am fluent in machine level coding on several platforms. I love this stuff and my #1 priority is enjoying my hobby, not to become the ultimate couch potato, so any project must incorporate these things in a major role. The time consumption is not my barrier to going the all custom route that would be the most fun for me, but the real issue is in the final goal I established for the plan noted above. That goal is 100% automation of every electric & mechanical device with integrated whole house multimedia all under a central control system that is accessed by a range of hardware & software interfaces - IE a multimedia GUI using RF, IR, wired devices, video, voice, internet, etc.
Much of this is too complex or expensive to build in light of all the existing cheap hardware & software out there today. The electronic control of electric or mechanical items is the area I will custom build, but the rest will incorporate commercial products that can be intergrated easily. X10 has software packages that meet some of these software and user interface capabilities and that's why I want to review it's possibilities to integrate my custom electronics. It may be the worst choice out there but with my existing X10 hardware, I thought it worth a looksie.
Your suggestion about subnetting my X10 setup is quite interesting to me. The difficulties you mentioned are not issues for me. I live in unregulated area as for codes, but I am quite skilled in basic residential electrical and I tend to go overboard related to meeting safety and capacities. For example all my wiring is in conduit with every strand of wire and jbox color coded and labeled to standard practice. So I already know on which phase every wire I've installed is on. My X10 reliability is also fairly high as a result of my wiring practice. All my X10 devices source power from it's own subpanel which I've isolated with blocking filters from the main panel. I also use multiple receivers, extended antenna's, odd house codes, etc, all of which has resulted in nearly perfect performance.
My only issue was the pc integration and software. Can't remember the device model of the transceiver, but it had batteries and locally stored macros that ran independent from the pc. Had 2 of them and both had spurious operation if they operated at all, thus my original questioning of the reliability for accurately reading or writing data to devices. My concern about the limitation of addresses was based on 1 bit per address relating to one IO line. However, your subnet suggestion noting the 256 addresses put my mind into hexadecimal mode. Using 8 X10 addresses I could write an IO address register that decodes to 256 devices and could read/write to that device at a 9th X10 address. That avoids the reliability issue using the dim/bright commands I thought of before.
For example, I can access 1000+ address by writing an address bit to 10 unique X10 addresses & read them back for near 100% reliability. Using a few more X10 addresses for status & control registers and 16 more X10 addresses for data lines, I would have a 16 bit wide I/O bus with 1024 addresses with just 2 full X10 house codes. Cumbersome software process but a viable one if I use X10. This process might be very familiar to others who remember the pre-386 days of the pc and the use of expanded memory.
Last comment in my novel here - what is Zig-Bee? likely another plc system but I've never dealt with it. I'll google it, but would like your input as we seem to have similar experience and tendency to creative re-engineering of stuff to fit our needs.