nivek@ROVER.RI.CMU.EDU (Kevin Dowling) (01/29/88)
Brian Reid's house automation project is similar to mine but larger in scale. My wife and I bought a house here about 18 months ago and we have totally gutted it and have been living in it. (camping in the city!) Building new is easier and better, and our next house will probably be from scratch. I have completely removed the old 'knob and tube' wiring and replaced it with a 200A service (40 full-height/80 half-height breakers) Every room has at least 1-2 Circuits (The kitchen has 8). The wiring I used is TRI/CON which combines 75-Ohm coax, 4 twisted pairs, and 2-12awg (shielded) W/ Gnd. Every room has a run of TRI/CON and the switchplate has a phonejack/ BNC or F connector/ duplex outlet. We're still at the point where all the walls and ceilings aren't up and I'll be adding central vacuum, and running some more wiring. I plan to use the excess twisted pairs for extra phone lines. All the wiring terminates at a large panel in the cellar and all patching and connections will be done here. I intend to use X-10 and eventually the new CSBus protocols in controlling devices. I have a large amount of information on Home automation stuff and will try to post a reference list of stuff to the net. There is a magazine devoted to this called Electronic House, the Magazine of Home Automation. Founded by another CMU alumnus too. nivek Aka : Kevin Dowling Bell: (412) 268-8830 Arpa: nivek@rover.ri.cmu.edu Mail: Robotics Institute Hacking Robots for Mars... Carnegie Mellon University Pgh, PA 15213-3890
dennisg@felix.UUCP (Dennis Griesser) (02/05/88)
According to recent postings, both Kevin Dowling and Brian Reid have incredible home automation projects in the works. I eagerly await progress reports and additional information on both projects. Cost information would be nice too. How much does it cost to run 25-conductor phone cable per room... One thing that made me sad was that we seem to be working harder but not smarter on this kind of project. Yes, I want to rip up the walls too. But isn't there a less dramatic way to do it? For example, Brian has > ...2 500-MHz video channels from the utility room to each room of the house, > and 25 twisted pairs to the same locations. > ...a bunch of random cables ... such as doorbell buttons, several thermostats, > exterior sensors, etc. I'm inclined to allow the video, but isn't 25 twisted pairs per room overkill? Especially since the stereo gets piped in through other wires. In a given room, the allocation might look like this: pair function ---- -------- 1 unregulated DC for smart thermostats and such 2 telephone 3 thermostat high-point for this room 4 thermostat low-point for this room 5 intrusion sensors (perimeter switch loop) 6 command console 7 air vent control ... and about five pairs RFU (Reserved for Future Use) That's still overkill! How about this one: pair function ---- -------- 1 unregulated DC for smart things 2 telephone 3 twisted-pair LAN (Local Area Network) ... and about four pairs RFU (Reserved for Future Use) Each room would contain one or more LAN nodes. The nodes would poll intrusion sensors and command consoles and ship the results to the home control center in the utility room. Commands from the control center would be received by the nodes and fan out to devices such as lamp controllers and air vent controls. The LAN nodes could be single-chip MCUs with very little support logic and an operating program in on-chip EPROM. The average node would have 8 digital input lines, 8 digital output lines, and a channel each for analog input and output. Hang a thermistor on the analog input and you can chuck the commercial thermostat. The lower-level LAN protocol could be simple indeed, if the control center simply polled each station in sequence. The node command repertoire might look like this: o tell me your digital input o present this digital output o tell me your analog input o present this analog output This is sufficiently general that you can do anything without special node software or hardware. System configuration and I/O interpretation are the duty of the control center. The protocol would include all of the "good network stuff" like error detection, timeouts, retransmission, ... If you are careful, a DC bias could be impressed on the twisted-pair LAN cable to power the nodes. Sounds like Kevin's TRI/CON wiring is sounding better and better. Such a LAN node should be buildable for about $10 per node in quantity. Perhaps $25 each if you build them yourself. Now, let's step back and try to avoid reinventing the wheel. SOMEBODY must have designed some such system before. I've never heard of it, but perhaps Kevin has. What's this "CSBus" protocol? What else is out there? How much does it cost? What can it do? Life, the universe, everything!
koko@uthub.toronto.edu (M. Kokodyniak) (02/06/88)
These days it just doesn't pay to run 25-wire cable to every room in the house. Just run two wires and use electronics to do the rest. Or better yet, use wires already in place -- power, telephone, cable-TV cables. (Of course this is the idea behind the X-10 system.) Remember: Silicon is cheaper than copper!
reid@decwrl.dec.com (Brian Reid) (02/11/88)
In article <20522@felix.UUCP> dennisg@felix.UUCP (Dennis Griesser) writes: >One thing that made me sad was that we seem to be working harder but not >smarter on this kind of project. Yes, I want to rip up the walls too. But >isn't there a less dramatic way to do it? There are different kinds of smarter. I am perfectly capable of designing custom integrated circuits to operate my doorbell, and such. I just decided it was better engineering practice to do otherwise. Let me explain why I did what I did. My going-in principles were as follows: 1. Every component must be off-the-shelf commercial material. No experimental or home-made stuff. I need to be able to sell the house someday. 2. Do not use active components where passive components will do. A piece of wire is much less likely to fail than a LAN emulating a piece of wire. Corollary: use low-tech active components rather than high-tech active components wherever possible (I built my furnace controller with relays and not with TTL, because relays are far less likely to fail). 3. Given several different ways of doing the same thing, always choose the one that is the most ordinary and/or the least expensive. This is why, for example, I went with 25 pair cables. 25-pair wire is the standard of the commercial telecommunications industry, and therefore is cheaper than 8-pair wire. Also, end connectors and jacks for 8-pair wire are many many times more expensive than 25-pair connectors. As an example, I bought a 1000-foot roll of 25-pair cable for $130 at a local telephone supply store. A 1000-foot roll of 16-conductor wire at the local electronic supply house is $400. The 25-pair connectors from Amphenol are $4 each, and there is a crimping tool that will install them. The 16-conductor connectors are $14 each, and must be soldered. 4. It has been my experience that most automation projects live and die by interface or I/O problems. The issue is not conceptually how to multiplex a doorbell circuit on top of a packet-switched network, but rather how to connect the wires from the doorbell button to the network. My 25-pair cables have ordinary telephone company modular jacks on the end of them, and it is easy to plug a telephone, a computer terminal, an intercom, a thermostat, a doorbell, or anything else I need into the modular jacks. The conceptual problem of how to implement the (physical or virtual) circuits pales in the face of the physical problem of how to get a nice-looking wall plate that can be used to make and unmake simple connections to it. 5. I tried not to solve problems that were just dreams. I do not at the moment own a toaster with an LAN connection, nor does any company sell one, as far as I know. Therefore I didn't worry about LAN toaster connections. However, I do own several telephones and several computer terminals, and I have frequentlyu wanted to be able to move them from one place to another, so I tried to solve the problem of comm-device mobility within the house. I didn't build a rocket landing pad in the back yard, but I did build a bicycle rack. Same principle. Be realistic about what the future is likely to bring. Wire will continue to be more useful than packet switches well into the next century. Brian