49 replies to this topic

[Pooky]

Not bought one yet, will do once I figure this out! Relays confuse me!

Are THESE the right relays? In one question they say they're 4 pin, in another they say they're 5 pin. Do they differ because some are SPNO and some SPDT? Is it an SPDT one I need?

[daemonchild]

The problem is the interior light feed is permanently live and will run to earth through the buzzer and bulbs. You can add a diode cheaply enough though.

I've not experienced this personally, but any flat battery problems in the future this will be my first port of call!

I built exactly this, but it was flattening mine, so I removed it until I get around to popping to Maplins for a diode...!
Edit: or I might try the buzzer the other way around... lol

Edited by daemonchild, 21 November 2009 - 09:21 PM.

[jmetal88]

The problem is the interior light feed is permanently live and will run to earth through the buzzer and bulbs. You can add a diode cheaply enough though.

I've not experienced this personally, but any flat battery problems in the future this will be my first port of call!

I built exactly this, but it was flattening mine, so I removed it until I get around to popping to Maplins for a diode...!
Edit: or I might try the buzzer the other way around... lol

I just built the circuit and hooked it up with the positive wire spliced into the green/red wire immediately behind the gauge cluster and the ground wire spliced into the purple door switch wire next to the driver's side door. I could verify that no voltage comes through the green/red wire going to the gauge cluster when the light switch is off by checking it with a multimeter, and the purple wire is clearly grounded, so I don't see any way it could possibly drain the battery on my car.

I got my buzzer at Radio Shack though since I don't know of any Maplins here in the U.S.

Edited by jmetal88, 21 November 2009 - 09:26 PM.

[Min E]

Not bought one yet, will do once I figure this out! Relays confuse me!

Are THESE the right relays? In one question they say they're 4 pin, in another they say they're 5 pin. Do they differ because some are SPNO and some SPDT? Is it an SPDT one I need?

Yes Pooky, you'll need relay # N00AW SPDT 12v.

You will also need UN42V Flashing LED £3.99 :



If you go back to the bottom of page 1 you'll see I've added a bit more information and the schematic.

It's important to realise that pin 87 will be live when the ignition is on.

Edited by MINY, 21 November 2009 - 09:43 PM.

[Pooky]

Nice one

[mini_mad69]

Bugger just fitted the Minispares kit to my Mrs' Mini! Going to fit a cheap buzzer to mine now Gonna do an alarm flasher as well.

This is a question on the listing, is this correct...

Q- How can i make this led flash when ignition is off but not when its on?

Answer- Connect the negative side of the led to a ground in the car and the positive side to pin 87a on an automotive relay, then connect pin 85 to a ground in the car and pin 86 to the accessory wire.

Theres an un-used pin on the back of my ignition barrel, when measured with a meter, it becomes live when removing the key. Connecting this to the +ve side of a flashing 12v LED and to ground, will give you a flashing LED which will only work with the keys removed. See if yours is the same, will be alot easier and cheaper. Mine is a 1985 car.



Ben

Edited by mini_mad69, 21 November 2009 - 09:57 PM.

[Min E]

Just a quick point.

Although the numbers given for the contacts are the standard ones for auto relays I have known some relays to use different numbers I've got a couple simply marked 1 -5 .

There should be a diagram of the internal circuit marked on the relay case. Refer to the schematic above and match the contacts to the drawing.

Any problems PM me.

[Min E]

Theres an un-used pin on the back of my ignition barrel, when measured with a meter, it becomes live when removing the key. Connecting this to the +ve side of a flashing 12v LED and to ground, will give you a flashing LED which will only work with the keys removed.



Ben

WOW!!! brilliant find. It will certainly work for you and dead simple....but are all Mini's fitted with this same lock?

[mini_mad69]

Theres an un-used pin on the back of my ignition barrel, when measured with a meter, it becomes live when removing the key. Connecting this to the +ve side of a flashing 12v LED and to ground, will give you a flashing LED which will only work with the keys removed.



Ben

WOW!!! brilliant find. It will certainly work for you and dead simple....but are all Mini's fitted with this same lock?

I have no idea, I assume earlier cars with smaller ignition barrels will not, mines 1985 so I assume allcars afterwards will have this.






Ben

[Min E]

If most cars have this facility then it could be utilised to drive a relay whose normaly closed contacts could interupt the low tension feed to the coil i.e. an extra security feature that normal 'hot wiring' would not get round.

The only problem with that is that there would be a small drain on the battery.

I think it's geting to the stage where this thread needs going through and separating up into different 'Hints & Tips' for individual pinned threads.

A job there for the Admin.

Edited by MINY, 21 November 2009 - 10:13 PM.

[chappy]

so what diode do i need to get for this to work? and not drain my battery...




Thanks

Sam


Oh and Miny.... LEGEND!!!!

Edited by chappy, 21 November 2009 - 10:13 PM.

[Ethel]

S'ok Miny, I appreciate your good intentions. I didn't mean argument in a toe to toe raised voice sense, more of a nerdy maths or science one



A couple of resistors and a mosfet or transistor won't be any more cost and effort than a relay.

[Min E]

so what diode do i need to get for this to work? and not drain my battery...




Thanks

Sam


Oh and Miny.... LEGEND!!!!

I really don't think you need a diode but fitting one will do no harm.

You could use any of several types of general purpose rectifying diodes. Go for a 1N4007 (Maplin # N78CA) cost 18p;



It should be fitted in the black wire from the buzzer that goes to the door switch and should be fitted with its band marking towards the door switch.

Edited by MINY, 21 November 2009 - 11:21 PM.

[Min E]

S'ok Miny, I appreciate your good intentions. I didn't mean argument in a toe to toe raised voice sense, more of a nerdy maths or science one



A couple of resistors and a mosfet or transistor won't be any more cost and effort than a relay.

I like those!!!!!

Very simple, and as you say, no more cost than a relay....although, with the greatest repect to our fellow members, possibly outside the scope of some of their circuit building skills as it would involve making a circuit board with fine soldering on delicate components.

This information about the 'spare' connection on the ignition switch is worth following up, do you know anything about it?

Edited by MINY, 21 November 2009 - 10:45 PM.

[jmetal88]

I just had an epiphany!

Ethel's right, but I didn't understand her/his (profile says male) explanation until now. When the door is closed and the buzzer is connected, the interior light circuit, instead of not earthing like it should be, will instead attempt to earth backwards through the buzzer and through the gauge light circuit!

There won't be enough current to light any of the lights, but it would drain the battery slowly.

I think I'll start looking for a suitable diode. I'm sure I have one around here somewhere. I think it would do best between the buzzer and the door switch wire, so current can't flow backward through the buzzer from the interior light circuit.

Edited by jmetal88, 22 November 2009 - 01:58 AM.