Pretty simple idea help

Hi all

First all, i'm pretty new here but I'm sure someone on here will be able to direct me.

I've had an idea for something I want to do for my cars internal lights, basicly I want to have one bulb in the centre console come on with the ignition, but be on very low and suttle, then when the door is open it comes on full.

So I was thinking, if I take a live from ignition live, run through a resistor, that would make it so it's on suttle, then have a second live from the interior lighting circuit to it as well.

Could someone direct me, will this be right and is there a way so that it passes a switch first, so when the interior is on it pics up that live, then when that one goes off completly it switches over back to the ignition live?

You need 2 of diodes.

Ignition live to resistor -\/\/\/\- resistor to first diode anode -|>|- cathode to light
Interior lighting live to second diode anode -|>|- cathode to light.

So the light should have 2 diodes (cathodes) connected to one side and other side is grounded.

Diodes like 1N4001 would probably work fine.

Hope that's clear.

Ray

Yea that's perfect

So if I do it that way, when the interior live is taken away, it will go back to the ignition live, then if the interior live comes back it will on that?

The light will always be bright when the interior circuit is live and always dim when the ignition is on. The bright will override the dim. It won't care what order the power is applied.

The diodes are really there to prevent the interior circuit from trying to power the ignition circuit and visa-versa.

Ray

That is spot on to what I want to use it for.

My plan is the light will come on with the interior light, but I was going to get one of these kits as well so that it fades in and out

**broken link removed**

Am I right in thinking that it will stay on, when the interior circuit is cut, dim till it's at its faded state?

if that makes sence :lol:

The light should dim as the interior light dims until it reaches the ignition brightness (assuming the ignition is on).

Ray

Awesome, that's spot on

much appreciated, now to go and purchase the bits I need

rhaynes said:

You need 2 of diodes.

Ignition live to resistor -\/\/\/\- resistor to first diode anode -|>|- cathode to light
Interior lighting live to second diode anode -|>|- cathode to light.

So the light should have 2 diodes (cathodes) connected to one side and other side is grounded.

Diodes like 1N4001 would probably work fine.

Hope that's clear.

Ray

Click to expand...

Hi,
rhaynes has defined it very well.
I wanna ask that if i want to use some diode other than 1n4001 then to which should i prefer?
Thanks

You are looking for a rectifier or power diode, not a signal diode.

PIV(Peak Inverse Voltage) or Vr(Voltage Reverse) should be >= 50V
Average Forward Current, safe would be 2 times > than the current of the lamp(s) driven at the bright setting.
Forward Voltage drop doesn't really matter but lower voltages will run a little cooler
Speed, Recovery and Capacitance don't matter.
Package - Pick one that works well with your wiring setup.

Ray