Using unlock as signal

[Jack]

Here's a question, one that came up on CCUK actually, but it got me thinking.

Lots of modern cars turn the interior light on for about 10 seconds or longer when the doors are unlocked. Now, I'm thinking how this could be done - use a feed from the door unlock wire from the alarm? My electrical knowledge isn't enough to figure out how though.

I did think about using a signal wire off the unlock feed, to a relay, which powers a circuit with lights and a capacitor on it. The capacitor could hold enough charge to keep the light on for about 10 seconds (my interior light does this already) but the unlock signal from the alarm will only be about 1 second, so not enough to keep the light circuit relay on long enough to charge the capacitor surely?

Any ideas on other ways to do this? I remember looking for OEM interior light delay relays on ebay a while back and didn't come up with much joy (those few that were on were either too expensive or too hard to figure out the wiring).

[Stuart]

you would have the signal trip a 10 second Monostable so that the relay/light is held on for 10 secs. (easy option)

or you could be poncey and have the alarm trigger the relay but the lighting control will only turn the relay off once its reached X time. (harder option)

[L14MNP]

10 sec trip FTW. Any point though? Nova interior lights are worse than a dead torch. Get a clapper, the CL solenoids may make enough racket to activate it lol

[Stuart]

10 sec trip FTW. Any point though? Nova interior lights are worse than a dead torch. Get a clapper, the CL solenoids may make enough racket to activate it lol

lmfao how cool would that be!!!

clap once for side lights, twice for normal beam, and three times for high beam

[L14MNP]

The only down side I see is the local yokels with their 12 bores will flatten his battery in no time lol

[Jack]

10 sec trip FTW. Any point though? Nova interior lights are worse than a dead torch.
Its not for a Nova :p

[edit] although I may use the nova to test it, see how well it works lol

[L14MNP]

LOL does your taarbo jap box not have a function which illuminates the interior courtesy lamp for you entrance/exit needs? :(

[Jack]

Only with the standard alarm unit I think. Which has long since gone on mine lol

[Stuart]

here you go bender boy
http://www.autoelectricsupplies.co.uk/product/175

[Jack]

Thanks hunny.

So that just sits on the interior light wire (-ve side), takes a +12v feed and a switch signal from the unlock wire, and should do what I want it to do?

[L14MNP]

No it will do what it wants to do as clearly it is capable of independent thought.

[Stuart]

infact I dont need to do you a diagram lol
http://www.autoelectricsupplies.co.uk/file_uploads/140207_wiring_diagram.jpg

12V from a permy live wire (with a fuse if you like)
I'd suggest taking the line from the "door switch" on that diagram to the wire that connects to the relay for your central locking

[Graeme]

I did it to mine Jack, I've installed a dimmer set up from an astra gte and switched the permanent earth to the light via a relay so when I lock the car it breaks earth. And then I unlock the car it makes the connection again and then (by pure fluke) it comes on also wired in the ignition live so when the ignition is on the light only stays for three seconds but when its off it more like fifteen. To feed the relay I just used the supply to the led which comes on when you lock the car

[mowgli]

might be off the wall a bit, but why not simply leave the door ajar for a few seconds??????????//

[Jack]

might be off the wall a bit, but why not simply leave the door ajar for a few seconds??????????//
Its not for leaving the interior light on when you're in the car, its so it comes on when you unlock the car from the keyfob

[Tidy Max]

No it will do what it wants to do as clearly it is capable of independent thought.

lol lol