root@conexch.UUCP (Larry Dighera) (01/18/88)
David: Regarding your message below: >To: Larry Dighera <ucla-an!conexch!root@cs.ucla.edu> >Subject: Leviton X10 products >Date: Thu, 14 Jan 88 10:56:51 PST >From: David G. Cantor <ucla-an!MATH.UCLA.EDU!dgc> > >Thanks for the information about Leviton. You're welcome. I hope you found it informative. > >Among other things you said: > > Leviton makes such a complete line of devices, that it is > completely feasible to have *EVERY* light, appliance, and > receptacle controlled throughout a building. If there are more > than 255, you must of course set some to the same code . . . > >There is a major flaw (problem) that you didn't mention. > > S E C U R I T Y > >How do prevent your neighbors from being able to interfere with your >devices? I.e., what if the 12 year old bright brat next door starts >playing with a controller and your garage door starts going up and down, >your porch lights flash, etc. This is positive reinforcement and he will >bring his friends and show them his powers. You are correct about this deficiency in the X10 system. In the paragraph following the one you included in your reply, I attempted to point out that the control loop wasn't closed in the X10 system. Here is what I said: || What BSR and Leviton seem to have left out is the closure of the control || loop; wouldn't it be nice to have the ability of inquiring of the on/off || status of the modules, so you could see if the module responded to your || command? It would also be nice to have modules that could send an || indication that a contact had closed. Of course, one would also need a || receiver for these. What I was trying to get across is that with the X10 system one sends his commands over the power wiring and hopes that they are acted upon; there is no indication that the commands were received nor if they were successful in accomplishing the desired task. What is needed are more intelligent modules capable of: 1. Reporting their current state when inquired. 2. Confirming their success/failure in executing your command With these additional attributes it would be possible to overcome the complaint you state above by continually interrogating the modules on the system, and confirming that they are still in the correct state. > >The only solutions I have found are two: > >1. You can buy a home isolation transformer. Cost is around $3000.00 > (perhaps a good deal less if you don't bother to isolate certain > high-wattage devices which you don't "control", e.g., electric > dryers, ranges, ovens, etc.). > >2. You can buy a low-pass filter for each circuit (at least 15 amp and > 20 amp circuits) you wish to control from Leviton, at about $70.00 > per circuit, and cross-connect isolated circuits with .1 microfarad > capacitors. > Thank you for sharing this information with me. I wasn't aware that these items were commercially available. Use of item one above would seem to be overkill in a home situation, but large commercial buildings are probably already being feed from their own transformers, and thus provided the desired isolation. The use of item two for isolation seems prohibitively costly on anything but a very few circuits. >Are there any other solutions? I have thought of building my own >filters, but the ferrite cores they use would bring the cost of parts up >to about $35.00 (at least in low quantity). Building your own filters sounds like a way of overcoming the cost, but what about satisfying the Building Code's requirement for UL's blessing? If the cause of a fire could be traced to your non-UL listed filter, your insurance carrier may be reluctant to pay off your claim. > >Are there any less expensive solutions? > Yes. You're not going to like this, but the way commercial installations assure that all modules are in their correct state is to continually command them to that state repeatedly, several times per hour (or minute in the case of critical modules). Although this is basically a kludge to work around the X10 system's shortcomings, it is relatively effective in overcoming the nuisance of spurious signals on the power lines causing a module to change state erroneously. Obviously this would not be too effective against a determined "bright brat". >I currently control all my computer gadgets (cpu, separate disks, >monitors, modems, etc.) AC power using the Leviton (X10) devices. >This eliminates the usual mess of AC wires and enables me to control >my printer (which is in a different room for quiteness). The computer >gadgets are spread across two circuits and I do use two Leviton filters, >cross-connecting the circuits, to protect them from the neighbors. This arrangement seems to be about the best solution for your particular situation. > >dgc > >David G. Cantor >Internet: dgc@math.ucla.edu >UUCP: ...!{ihnp4, randvax, sdcrdcf, ucbvax}!ucla-cs!dgc Although you don't explicitly state so, I assume you are controlling your system manually rather than with your computer system. In this case the modules have no way of discerning your _valid_ commands from those of an intruder's. If, however, your X10 system were completely computer controlled by your Unix system via a "Powerhouse" controller, the addition of one item (which unfortunately doesn't currently exist to my knowledge) could overcome an intruder's attempts to take control of your X10 system. Suppose your "Powerhouse" RS232 controller had the ability to receive X10 commands as well as issue them. If it would send an indication of all commands it detected on the power wiring to the host computer via the RS232 link, they could be compared to the event schedule. Those that were in error could be overridden by issuing a counter-command to assure that the current state of the X10 system remained in conformance with the event schedule. Thus, if the "bright brat" commanded your porch lights on, the computer would immediately command them off. This is far from a perfect solution, but one that could probably be implemented easily. Although the X10 system is very useful, even in commercial applications, it is really quite limited. The limitations on the number of modules that can be controlled and the issue of security probably caused the designer to omit features that would have been included in a control system designed expressly for commercial application. Fortunately, this resulted in a usable system at a reasonable price. Thank you for your reply and the information it contained. Best Regards, Larry Dighera -- USPS: The Consultants' Exchange, PO Box 12100, Santa Ana, CA 92712 TELE: (714) 842-6348: BBS (N81); (714) 842-5851: Xenix guest account (E71) UUCP: conexch Any ACU 2400 17148425851 ogin:-""-ogin:-""-ogin: nuucp UUCP: ...!ucbvax!ucivax!mickey!conexch!root || ...!trwrb!ucla-an!conexch!root
faunt@spar.SPAR.SLB.COM (Doug Faunt) (01/22/88)
I am interested in home automation, although I donn't think there's enough traffic in sci.electronics to justify a dedicated group. There's a not-very-good magazine dedicated to the subject, called Electronic House, PO Box 1347, Elmhurst IL 60126-1347. It's $15.00 a year, for six issues. They do have some useful information, some confusing mis-information, and some blather. The one I have in my hand has 32 pages. >Although you don't explicitly state so, I assume you are controlling >your system manually rather than with your computer system. In this >case the modules have no way of discerning your _valid_ commands from >those of an intruder's. If, however, your X10 system were completely >computer controlled by your Unix system via a "Powerhouse" controller, >the addition of one item (which unfortunately doesn't currently exist >to my knowledge) could overcome an intruder's attempts to take control >of your X10 system. > >Suppose your "Powerhouse" RS232 controller had the ability to receive >X10 commands as well as issue them. If it would send an indication of >all commands it detected on the power wiring to the host computer via >the RS232 link, they could be compared to the event schedule. Those >that were in error could be overridden by issuing a counter-command to >assure that the current state of the X10 system remained in conformance >with the event schedule. Thus, if the "bright brat" commanded your >porch lights on, the computer would immediately command them off. >This is far from a perfect solution, but one that could probably be >implemented easily. > There is a device available from Enerlogic Systems, Inc., 4 Townsend West, Ste. 3, Nashua NH 03063, +1-603-880-4066, called the ES-1400, for which they want $395., which includes PC software, that is a more complete RS-232 to X10 interface in that it does receive and relay X10 signals from the line, and pass them on to the computer. There was mention of a Unix program to control a "Powerhouse" unit. Does anyone have a more complete pointer to that? ...{amdahl|decwrl|hplabs}!spar!faunt faunt@spar.slb.com
bakul@amdcad.AMD.COM (Bakul Shah) (01/23/88)
In article <389@spar.SPAR.SLB.COM> faunt@spar.UUCP (Doug Faunt) writes: >There was mention of a Unix program to control a "Powerhouse" unit. >Does anyone have a more complete pointer to that? I have a simple program for this. It provides a command line interface to most of the powerhouse functions. Example: x10 setevent 0 normal mon-sun 8 30 1,5-7 on x10 setevent 1 normal mon-sun 9 00 1,5-7 off will turn modules 1, 5, 6, 7 on at 8:30 and off at 9:00 AM everyday. You can also write a script of x10 commands to be called by, say, cron. BTW, the powerhouse unit keeps pretty good time and I use it to keep my Fortune 32:16 from running ahead of time. I have another little program for this since Powerhouse doesn't speak seconds and you have watch for the exact time when the minute ticks over. Email to my address below if you are interested. -- Bakul Shah, ..!{ucbvax,decwrl,sun}!amdcad!light!bvs
P4O@PSUVMA.BITNET (02/03/88)
I would just like to ad that I bought a X10 computer controller for
$15 for comodoore and rewired the output for 8-bit Atari
I have no suck problems,and my next door neighboors have the same units.
I was suprized to learn that there were no problems with this.
A exellent deal for the price.