dimmer?

Velleman K3500 kit will do what you want.

oldspark wrote: Which blew? The smaller Q1? Sure the CBE orientation was correct? (Trannies can be bricks - especially TO-92 packages - they have a "standard" called TO-92(var) - the "var" is various/variations etc which cover most combinations!) That's where a DMM is handy - I used to do a resistance check, but these days they include diode/continuity checks, and transistor (gain) checks (not that I have ever use it...) And there is another circuit for "external" shutdown, though I think that was triggered by the beam switch... but IGN is the same thing... in fact why not diode-OR to have both of them? (I think the Jaycar kit includes that).

i'm not going to lie, that was completely over my head ha. but yes, one of the q1's blew. i was testing it all out on a bread board. the first time, one of my terminals started smoking. so i disassembled it and started fresh. the second time the led stayed on at all times and when i pressed the button(acting as my door switch) the led dimmed just a tad and stayed like that. so once again i started from the beginning, then it blew. i even triple checked everything! gah!

howie ll wrote: Velleman K3500 kit will do what you want.

i will check into that, but i'd much rather learn to build my own, as this is the kind of stuff i enjoy doing as a hobby.

Yes but as a pro I haven't time to fluff around like that. The next method is to use a DEI 528t, with a relay to interrupt the power supply when the ignition is turned on. You can run it up to 3 mins.

i can understand that. may'be i'll get to that point sometime :)

It's OK, I spent 3 hours earlier today disassembling the lock mechanism on a BMW 850 to find the one micro-switch out of 3 which was stopping the remote key less, the dome lights and the full window close from working. It doesn't match any thing in the catalogues so it's over to my local BMW stealer on Monday. Why 3 micros switches? So if one goes wrong it takes everything else out.

Sk8r - are you only testing with LEDs, or do you intend using it with LEDs? The circuit is designed for bulbs, not LEDs. Use a 5W or 10W bulb for testing....

howie - dang, that's about ridiculous. i under stand why people say beamers are so expensive to work on! oldspark - DUH! i completely didn't even think about that.. i was testing with LEDs. the circuit would be powering 2 cold cathodes, 6 LEDs, and 1 halogen bulb

Two threads here I know but out of interest, shut the door, the glass drops 1" to vent, hold the lock over for comfort close, pull up on the door handle and it brings on the interior lights, all controlled by various micro-switches around the lock mechanism, never seen such a complicated mech.

sk8rjess - STOP NOW! That circuit is only good for (say) 10W. Also, such "analog" circuits are only good for tungsten etc bulbs, and to an extent - halogen bulbs (but they drop off quicker). They are NOT suitable for LEDs, cold cathodes etc. You need a PWM circuit. The advantage is that one MOSFET will drive the lot (ie rated for 60A etc). PWM circuits are simple enough, the problem is the dimming... Not that I searched too hard for a complete circuit (that didn't involve PICAXEs & uPCs etc), though I think I came up with a suitable mod to my 555 PWM circuit. Now where did I leave that memory? FYI - the 555 PWM circuit is shown tex at mp3car-137810-changing-cold-cathode-backlighting-leds-auto-brightness-control-3 page 3 - Reply #40. [ Well what do you know - I seem to be replying to my own replies... And there's another Swede! And he owns a BMW too! What a coincidence.... But all that trouble because his cold cathodes weren't dimmed through his/its power supply. I guess some people just like doing things for the sake of it eh? ] If I recall, I added some constant-current capacitive charge or discharge circuit to the 555's front-end (ie, pin 2 or 5 or 6). But recently I found an automotive PWM fan controller that might suit....