dimmer?

i fried the part on my BCM that controlled my dimming/courtesy lights when the doors shut. now i've deicded to redo them using my own module. my truck is a 2002 toyota tacoma. when the doors shut, the button the door hits is grounded out. i'm assuming that would make it called negatively switched(ha).

this is the diagram i'm going off of
https://goldsswagon.com/domedimmer/domelightdimmer91.htm

my question is what else would i have to add to make the lights go off if the key is in the "on" position?

I have no idea about your vehicle, but most vehicles have an open circuit when the door is closed, and grounded when the door is open.

heh.. that's what i meant to say :) you are absolutely correct, i didn't realize i wrote it that way.

Or as posted in interior light dimming to off, a simpler circuit.... (well, one less transistor..)



... and its birdsnest layout:

that's the thread i was going off :D i took a parts list for both circuits and radio shack (2 different ones) didn't have all the things i needed for that one. for that circuit i only got the resistors, the 47uF cap, and the 2n3055 trans.

could i sub the em401 and 2n3638 for something else?

That circuit is from 1985.
Or was it 1885??? (Let's see - did I fit it to my car, or to a horse buggy?)

The diode would now be something like an 1N400x - eg, 1N4004, 1N4007 etc. (That's a 1A diode with 400V PIV or higher; a 4001 is a 50V rating & 4002 a 200V rating (I think), but the 400V IN4004 is cheaper and more common...)
The diode is not that critical - it just has to carry the capacitor discharge current (well under 1 Amp) and tolerate 12V systems - eg, >16V means a 50V rating, or 200-400V if voltage spikes are around...

The 2N3638 can probably be almost any PNP transistor...
aha! the 2N3638A is a 500mA PNP transistor with a gain of ~100.
Equivalents include the BC328.
I reckon the PN200 would also do....
... and probably any PNP transistor that handles 500mA.... (Not that I was ever good with transistors, but I'm reasonably confident it's not that critical (it's config'd as an emitter follower??) - the main issues are the heating of the 3055 over long delays or multi-cycling; and that's its case is "live" (but in a non-destructive way).)

And shove an ignition controlled relay across this to break the power when the ignition is turned on thus shutting down the dome lights. I believe Velleman market a kit which incorporates ign shutdown.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

i have some playing around to do first. i attempted a circuit last night and blew a transistor. for now i just wired them to come on when the doors open - no fading. i need to learn some more

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).

Velleman K3500 kit will do what you want.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

oldspark wrote:

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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).

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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:

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Velleman K3500 kit will do what you want.

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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.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

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.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

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.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

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....

i was thinking i could just use a module that would start at lets say 12v output, and every 1/8th a second drop a volt until it reaches 0v ha.

apparently it's not that easy :)

If you could dim those loads with voltage drops, you'd just use resistors (maybe thru transistors), or the dimmer circuits shown before.

i'll mess around a bit and if i have any more issues(i'm sure i will) i'll come back here. thanks oldspark :)

This is starting to sound like a right kludge with lots of potentially expensive pit falls. Just use a 528t and a mini relay as an ignition interlock.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

I thought the issue was dimming various "dome" lights.
Hence the dimming circuits. But since different "non-tungstens" are being used, such voltage dimming circuits are not suitable.

But I'll wait for the sk8r to return....