Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!sco!deanr From: deanr@sco.COM (Dean Reece) Newsgroups: sci.electronics Subject: CARNET - Automotive Electronics Keywords: Automotive Electronics Computers Mobile Power Systems Communications Message-ID: <7591@scolex.sco.COM> Date: 27 Aug 90 23:35:16 GMT Sender: news@sco.COM Reply-To: deanr@sco.COM (Dean Reece) Followup-To: sci.electronics Distribution: na Organization: The Santa Cruz Operation, Inc. Lines: 95 Hello, I've got a rather large project going and would like suggestions from the net. I have seen several postings related to automotive electronics, but none are quite as in depth as what I would like. My basic project is a high tech system to control all the electric/onic functions of the car. Note: ALL ARTICLES ON THIS THREAD SHOULD CONTAIN "CARNET" IN THE SUBJECT LINE SO THAT UN-INTERESTED READERS CAN MAKE USE OF KILL FILES. Please, no flames for how silly this may sound; At this point I'm just doing research and trying to learn some specifics about the idea. The basic scope of the idea is as follows: To replace the entire wiring warness (control and sensing circuits) with a network controlled by a central computer. I've intentionally avoided limiting information because I would like to see what the net can produce that I would never have thought of. The basic division of topics as I see it are as follows: 1) Central Computer: Should be fault tolerant or at least able to fail in a graceful way. I would like to see a multi-processor system. One processor is rather simple and runs all the time. It would control the communications with the net and provide simply services like clock, alarm, diagnostics, and COPS (Computer Operation Properly System) to the primary computer. The COPS computer should be as simple and reliable as possible. The main CPU should be more powerful (say 68000 class). At the least, it should integrate the dashboard with the devices on the net. At most, it could be a full computer with electronic maps and a GPS decoder (Global Positioning System). 2) The network: Should be very reliable in a noisy environment. Optic Fiber would be nice, but perhaps not the best solution. Topologies and protocols should be discussed. I see a Star network with the Central computer having 8 point-to-point optic-fiber links. 3) Power Supplies & Distribution: Sort of speaks for itself. The logic needs rock solid power, and the lamps and other electro-mechanical devices need a rough (raw battery?) supply. Assume the cars alternator and battery is still used (no atomics please :-) though dual battery systems might make sense. I assume that most people will be interested in 12 volt negative ground systems, though that isn't a restriction (make sure and say if you're writing about a different system) 4) Network Devices: These boxes would be mounted throughout the car and would act as the network terminals. A basic system might consist of the optic fiber net discussed with each net device capable of driving 8 or 16 devices. One box in the trunk, one in the passenger compartment, and one or 2 in the engine compartment should do. Note that most of the switching done in a car is simply for lights or other motor/coil type devices. Switching technologies: SCR/BPT/MOSFET/Relay... I would like some simple sensing on each driven line to determine if current is flowing (easy way to determine if a bulb is out). The boxes might need a "power-down" mode in which everything is off, but sensing on a few contacts continues and can alert the COPS computer if the state changes (like for an alarm system). 5) Audio Systems: Perhaps the most important part (at least most likely to get implemented :-). I would be interested in OEM type tuner modules that get fed +12vdc, a few digital signals (frequence, local/dx, and so on) and produce a left and right output (OK, an antenna input is needed). I've got a portable (Sony) CD player to use, and it has a remote control jack so I can send it commands (other ideas welcome). OEM type tape decks would be nice, but since they are rather mechanical, I doubt you could match the quality/functionality of an off-the-shelf Kenwood (pick your fav) with an affordable OEM unit (Again, I want something sort of like a floppy drive: Give it signals and it starts/stops/and steps as you command, providing nice clean audio in return). I want my big CPU to do all the stereo control. 6) Technologies: CMOS/TTL... linear/switching... solid state/relay... 7) Human Factors: For the new dashboard layout. Switch types, display types (LCD, LED, ELD, CRT). Icons -vs- text labels... 7) Legality: How legal is it to drive a car on a public road with mods this extensive (Street Legal) ? - probably belongs in some other newsgroup, but interesting here anyway. 8) Misc: Neat new ideas for making this system useful, and not just a toy. One idea is to have a short range (100 ft) transceiver attached to the antenna. The system could monitor the signal until it got a 'wake up' signal, then the xmitter would come alive. This would allow a certain amount of easy info interchange to the car without a cable. (The car should keep a maintenance log, perhaps a database of names/ addresses/phone numbers...) I can come home after work, flip on my PC and update my car's databases with my PC's latest. This might even go so far as to allow the car to warm itself up, if needed. What about cellular phones? I've never even used one, but they could have a great deal of potential in such a system (again, anybody know of cellular phone modules with CPU type interfaces?) References to related information or research will be gladly accepted. Thanks for your time and attention - Dean Reece - deanr@sco.com