49 replies to this topic

[Min E]

Having (I hope) sorted how to cheaply resolve the issue of 'back lit switches' raised in the 'Show me the light' thread:

http://www.theminifo...howtopic=141271


I suddenly realised that there is a very simple and cheap way to fit a headlight reminder buzzer.

Maplin sell a range of 12v buzzers like this:



Which cost from £1.99 (their code # FK82D) and go up to about £4 for a multi-tone one.

You can even get a 'Two tone siren' one for £3.79 (KU65V)
http://www.maplin.co...x?ModuleNo=3224


All you need to do is connect the buzzers +ve wire (red) to the red/green wire at the fuse box (side light fuse) and the -ve (black) wire to the purple/white wire that comes from the back of the door curtesy light switch.

Hey Presto.........Job done.

If your lights are on when you open the door the buzzer will buzz, whether your ignition is on or not.

Put these two threads together and you've saved over £30 with virtually no extra work because all the same connections have to be made with the module.

Edited by MINY, 21 November 2009 - 04:31 PM.

[robtheplod]

Yes, done this on mine and it works very well. If the buzzer is too loud/annoying just put insulating tape over it to muffle it!

[Ethel]

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.

[robtheplod]

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!

[Min E]

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.

It's not the interior light feed that is used, it's the switch wire which earths when the door is opened, yes although there may be some residual voltage through the bulb both the bulbs impedence and the fact that any voltage would be going into the -ve side of the buzzer would prevent the buzzer sounding.

It can't run to earth because nothing is earthed.

robtheplod...did you fit a diode in yours?

Edited by MINY, 21 November 2009 - 08:11 PM.

[robtheplod]

robtheplod...did you fit a diode in yours?

No, just a small buzzer spliced between the sidelight wire (+) and the door switch wire (-).

[Min E]

robtheplod...did you fit a diode in yours?

No, just a small buzzer spliced between the sidelight wire (+) and the door switch wire (-).

Yep...that's all you need!!!!!!

[Ethel]

There's only one wire on the door switch so if you connect to it you're adding the sidelights to the circuit. The current flow won't be much but it will flatten the battery given long enough.

[Min E]

Sorry Ethel, I think we've got ''crossed wires'' on this one.

The wire at the back of the door switch is effectively dead, it goes to earth when the door is opened thus completing the curtesy light circuit.
The bulb itself is, as you earlier stated, fed with a permanant live feed

If you were to connect a buzzers -ve wire to the door switch and its +ve wire to a permanent live then the buzzer would buzz every time you opened the door in the same way that the curtesy light comes on....yes.

In this instance we will be feeding the +ve of the buzzer with a live which is only present when the side lights are on...so, the buzzer will only sound if the side lights are on and the circuit is completed by opening the door.

There is no short, there is no connection between the sidelight and the curtesy light circuit. The only way the battery will drain is if you leave your lights on.

The buzzer unit is itself 'directional' so there should be no 'feedback' between what is effectively the residual, impeded +voltage from the curtesy light and the also + voltage coming through the buzzer (but only when the side lights are on anyway). You cant short two +'s

Edited by MINY, 21 November 2009 - 08:05 PM.

[Ethel]

It would depend on the buzzer, but I have actually just measured one I had kicking about. 0.2A @ 6V but 0A when connected the wrong way round so yes it can be done.

[Min E]

Surely the schematic is this:



With the +ve to the buzzer only live when the side lights are on.

Edited by MINY, 22 November 2009 - 11:31 AM.

[Ethel]

You have won the argument as it seems there's a good chance the buzzer will be directional - makes sense considering how they are likely to be used.

12v
l
\ light switch
l
l-----buzzer-----12v from interior light
l
l
0 side lights
l
Earth

[Min E]

I hope you are not looking at this as an argument Ethel....It's a discussion and I, as will I hope all who read it, have learned something from it.

I did jump in with both feet with the idea. Your considered opinions, for safety's sake, ensured that my whim should not cause possible elecrical faults. And there is no reason why a diode should not be added to guarantee it.

Dave.

Edited by MINY, 21 November 2009 - 06:36 PM.

[Pooky]

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.

[Min E]

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.

I assume you've bought a 'flashing' LED.

The relay will need to be one with 'change-over' or normally closed contacts. If it's got 5 terminals it's right.

The connections you have mentioned are right but you will also need a permanant live from the brown wire on the fuse box to pin 30.

Wireing it like this will make pin 87 live when the ignition is on so the terminal should be insulated or you could use the facility to drive something else.

To prevent pin 87 becoming live simply swap the connections: connect the LED to pin 30 and the permanant live to 87a

Schematic:


I fitted one to danny's car in the plastic cover next to the ignition switch. It can be easily seen from ouside the car and illuminates the key hole. It is also thin enough material for the LED holder to clip into nicely

Edited by MINY, 22 November 2009 - 10:37 AM.