car interior light circuit

[jason1983]

Hi I'm Jason, I'm trying to design a light circuit for my car. I'm not new to electronics but designing using semiconductors is not my strong point. I'm hoping I'm in the right place for some advice? Basicly what I'm after is a circuitry that fades the interior light on when the car is unlocked an stay on until either a certain time has lapsed (60 seconds) or the car ignition it turned on or door is locked again. Also the original  0v door open/closed signal must work.  When the light goes out I also need it to fade out. I would be very gratefully for some advice please. Many thanks Jason

[DmitryL]

Hi I'm Jason, I'm trying to design a light circuit for my car. I'm not new to electronics but designing using semiconductors is not my strong point. I'm hoping I'm in the right place for some advice? Basicly what I'm after is a circuitry that fades the interior light on when the car is unlocked an stay on until either a certain time has lapsed (60 seconds) or the car ignition it turned on or door is locked again. Also the original  0v door open/closed signal must work.  When the light goes out I also need it to fade out.

IMHO the main problem is how to get state signals you need from your car (locked/unlocked etc.), i.e. to know when do you need to switch lights on/off.
The rest is very simple. For example,  for my Honda jazz I made a  LED interior light "module" that replaces standard bulb and fades in when the power applied. You press that light, and it gradually increases brightness within 5 seconds or so. Nothing but a bunch of LEDs, a PIC controller, small FET, and other small parts. The solution is simple, because the circuit has only one signal - power

[jason1983]

Hi thanks for your reply, I can get either a pulse 0v or 12v for both the lock/unlock signal.

[Rerouter]

for the fading it would be more economic to use a cheap micro (look up arduino and attiny if you are new to it)

then you just have your permernant power connection, the lock status, and the ignition status going in, you use something like an NPN transistor to handle the switching / fading of the light with the micro controlling it,

so for that you could get away with, 1x LM7805 (and supporting parts), an attiny chip (crystal and reset resistor maybe), 2 resistor dividers for the inputs, and a NPN with base resistor,

for the code, they have on there site examples for fading an LED, all you would need to do is tweak it to happen when your inputs are triggered,