deanr@sco.COM (Dean Reece) (08/28/90)
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.combkoball@cup.portal.com (Bruce R Koball) (08/29/90)
Re: Dean Reece's proposal for networked control of automotive electronics... The Society of Automotive Engineers has developed an automotive multiplexing standard over the past couple of years...it's called the J1850 bus... Texas Instruments and Motorola going to be producing (under agreement with Delco Electronics Corp.) data link controller ICs that will interface their micro- controller families to the J1850 network....also, be careful using the name "COPS" for a microprocessor product, it is a trademark of National Semiconductor, used for their microcontroller lines. Bruce Koball Motion West 2210 Sixth Street Berkeley, CA 94710 415-540-7503 bkoball@cup.portal.com p.s. the above mentioned information is covered in an article "Delco drives net-IC pact" by Terry Coslow in the 20 Aug 1990 issue of EE Times.
rhaar@rcsac2.uucp (Bob Haar CS50) (08/29/90)
Newsgroups: sci.electronics Subject: Re: CARNET - Automotive Electronics Summary: Expires: References: <7591@scolex.sco.COM> Sender: Reply-To: rhaar@rcsrlh.UUCP (Bob Haar CS50) Followup-To: Distribution: na Organization: GM Research Labs, Warren, MI Keywords: Automotive Electronics Computers Mobile Power Systems Communications In article <7591@scolex.sco.COM> deanr@sco.COM (Dean Reece) writes: >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. Before you go much farther with this, I have two suggestions: 1) This discussion should at least be cross-posted to rec.autos.tech - a news group set up for technical discussions of automotive issues. 2) Check out what is already happening in the automotive world. Much of what you suggest is already is place or in the works. Vehicle manufacturers have been using proprietary networks in cars for about ten years. For example, GM has two distinct networks in use, one for connection engine controllers to body controllers, etc. and another used within the entertainment and comfort systems. Other car makers are using their own systems. Since these are proprietary, I cannot say much about them here. For the past four or five years, the Society of Automotive Engineers (SAE) has been working on industry wide standards for in-vehicle networks. There is one recommended practice (sort of a working standard) in place now that will be in production in 1994. This is referred to by its document number (J1850). J1850 is aimed at linking computer-based modules that exchange information but don't do time-critical control over the link. J1850 is being required by the Calif. Air Resources Board for all vehicles in California for diagnosing emission equipment starting in 1994. SAE also has work going on looking at protocols for load-control mulitplexing (commanding simple actuators such as lights) and high-speed protocols for real-time control such as active suspensions and traction control. Many papers have been published within SAE on these topics. Besides the automotive people, a number of electronics companies have been active in this effort - e.g. Intel, Motorola, and TI. Similar efforts are under way in Europe (under ISO) and Japan (JSAE), but with different motivations and directions. If there is interest, I can post some articles describing these efforts in more detail. I am a member of the SAE Vehicle Networking Committee and as a computer scientist at GM, I work with distributed architectures for vehicle control. -- Bob Haar CSNET: HAAR@GMR.COM UUCP: uunet!edsews!rphroy!rcsac1!rhaar Computer Science Dept., G.M. Research Laboratories DISCLAIMER: Unless indicated otherwise, everything in this note is personal opinion, not an official statement of General Motors Corp.