been thinking about security for locosts and came up with this idea for a bit of security.

basically it'll just be a female connector somewhere out of sight to cut a few important circuits, with a dongle/key (male connector) that acts as a bridge to make a few circuits live (and the car startable)



something along those lines (hope it's reasonably clear)

*BUT* rather than the 2 circuits and 4 connection plugs, using say, 3 circuits in a 10 connector plug, with all unused connectors in the plug containing dummy wires to make it near impossible to guess the setup.

unfortunately, it wouldn't be SVA compatable (could be used while engine running) so i'm considering maybe using a solenoid to lock everything together while the engine's running.

hope i'm making sense (first time for everything)

cheers
alex

perhaps you could just use it to cut the starter relay feed? if you use a 10-way connector with 10 wires the same colour going into it, it would still be pretty difficult to hotwire. If you wanted to be clever you could make it so that hooking up any of the other wires set off an alarm.

Using a solenoid to lock it sounds fiddly and prone to failure, to me.

Excelent idea.
Just a thought to try and make it sva complient , if you were to add a relay like the picture below the engine would stay running even if the immobiliser key was removed... ....

Julian, the relay etc sounds a good idea, should do the trick niceley.

like the alarm idea blueshift, i reckon that'd be easy enough to do, just require the same style gadgetry as julians idea to make it work well

[Edited on 9/3/04 by Staple balls]

For sva, cant the immobiliser turn off the engine. I was just going to use a hidden battery cut off switch for simplicity.

Stapleballs - would you be interested in making your self a bit of money and making a few of these. There was an idea a while ago about a diy keypad immobiliser but it never got anywhere.

but i'm not really too hot on this electrickery lark.


added you to my msn

For SVA, you need to have a device that imobilises the car, ie a steering lock as fitted to the donor, or a battery cut off switch is ok, so the device being described here will be ok as it prevents the car being started and driven away

Jason

quote:

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Originally posted by Julian B
Excelent idea.
Just a thought to try and make it sva complient , if you were to add a relay like the picture below the engine would stay running even if the immobiliser key was removed... ....

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is there really any need for a relay? say, if we only cut the starter solenoid wire [B/BL] as far as i know that'd only stop the car from being started, and wouldn't affect it once running. which i *think* would fall inside sva rules

I dont think so

if you turn on the ignition without the immobiliser dongle the relay will not work.

When the dongle is inserted the relay fires and then it self latches until the ignition switch is turned off.

To restart you would need the immobiliser dongle again

. This idea can be taken one step further and instead of a simple hard wired dongle a digital signature system could be devised.
All you would need was two off the shelf chips, one for the dongle and one for the relay.
If the code in the dongle key matched the code on the relay then it would fire the relay.
You could probably make a simple system up for about £25ish.
Citroen used to use a very similar system in their remote central locking systems
Anyway i digress

got any info for the relay i'd need? a tad better diagram would help too

as for the chip etc, yep, that's a good idea, but a lot of hassle/effort, and a little too much techmagical

cheers

Just had a look at maplins for connectors and a plastic case, came across this;

Key Module

As it switches a relay, im sure it could be used for this method. Not too much for £25.

Staple balls, you havent been added to my msn for some reason?

i added you using the info in your profile and you appear in my list, just not online

Whats your donor vehicle and do you have the haynes manual wiring diagram?
If its sierra i will have a manual oher than that can you scan the page and upload it?


The relays you can buy for 3 or 4 quid from rswww.com. try part number178-2012 £3.89, Its a relay capable of switching one 30amp circuit.
Alternativley, most 4 or 5 pin relays from the scrappy can be used, idealy go for the high current ones that switch the headlight circuits. You will require one relay per circuit or if you are lucky you can get a multi pole relay but they are a bit difficult to get hold of.
The only other thing is to try and steer clear of putting a relay in the starter motor circuit becuse of the higher currents involved,

Hope that helps

ah, I knew there was something I could be doing at work to do with the car.. I was going to have a crack at a keypad immobiliser myself, PIC-based.

prob be awhile before anything comes of it, but if I get one working I would be happy to build more of them for people. I'll shout if I do.

Keep us updated blueshift, theres a customer here...

I have used one of these to make my retrofitted central locking / immobiliser a code hopping jib. It?s very easy to use, and if you can?t be bothered they sell ready built kits that you could probably adapt.

http://www.electronic-kits-and-projects.com/30a16.htm

Scott.

surely all you need is a hidden switch to the coil feed OR a switch to short across the circuit breaker.


atb

steve

all you need maybe,

but that's hardly gonna stop a scumbag is it? takes all of 3 seconds to bridge a switch.

on the other hand a 10 pin plug, 8 of which are wired to an alarm is gonna cause some real hassle

quote:

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Originally posted by greggors84
Keep us updated blueshift, theres a customer here...

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well i agree with you both

The thing is only to make it difficult to start. if you have a theiving git who is also an electronics engineer the security system will only be as good as your electronics knowledge,
I managed to crack citroen's 65000 possibilities code system in about 1/2 hour ! and i was selling replacement fobs to the local garage fo £20 a go.
Hiding a switch is by far the best way to go ...but if you realy want to pinch a seven then 4 blokes and a trailer could pick it up and walk away with it.

Make it scream and make it difficult


Cheers

at the end of the day, all mr scumbag needs is a bit of wire. He can bypass all of the immobiliser stuff by just connecting battery to the coil +ve and getting his mate to push start the car......

there are ways around most things.

the grounded contact breaker would be subtle.....


atb

steve

[Edited on 9/3/04 by stephen_gusterson]

I was planning on just using a battery cut off switch, but this can be operated when the engine is running, which is a fail for SVA ive heard.

quote:

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Originally posted by stephen_gusterson
at the end of the day, all mr scumbag needs is a bit of wire. He can bypass all of the immobiliser stuff by just connecting battery to the coil +ve and getting his mate to push start the car......

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