10-11-2005, 11:32 AM
I am a bit of a bodger when it comes to electronics but i have a few ideas for a rudementary design. Jerry is the guy that wants to do all the fancy PICs and what not and the frodo and the guys from AIMEE want to do all this crazy PC controlled stuff.
If you use msn we should have a chat some time. Maye sure you have the latest version se we can do some sketches.
10-11-2005, 12:33 PM
with all the posting you do here, you still have time for im
I don't thave im,.... I downloaded trillian once but never screwed with it much......
I found this on a quick search...... this is why you would need to go with fancy electronics..... you need to read the referance voltage created, then convert to a usable pwm signal........
mine is different...... my pwr supplys already do all the dimming.... they need a variable resistance to control intensity.... with three I need around 2.5-3k resistor to control brightness..... I can trim & overide within the circuit, theres no logic involved.... a photoresistor is just that as far as I know, don't know the values yet, but this should be a google away....
this resistance is from 0, which is shorted(max brightness .... >to 2.?k which will be full dimming without going out
I need a photo resistor that does 2k...... maybe more control with 1.5k? I think I'll have to try to get a few different & play....I could also put one of these in series with an adjustable to have an adjustable variable, I think I could also put a pre determined added dimming when the driving lights are turned on... say add .6K to circuit when lights turn on... this should be real simple unless these resistors aren't available in a range to suit my needs I think????....
finally, since my lighting is set up in three seperate zones, I could have three photosensors....... bottom, middle & top of screen....... this screen is huge & most of the time it's only the lower part that is washed out by the sun..... my backlighting can compensate by boosting only where needed..... the top of the screen is under a little bit of an overhang.... this may need a little turn down depending on ambient light..... I could have 1 main sensor for overall tuning, & then 3 seperate auto fine tuning sensors........... I set this up in three zones with this in mind.....so this would make this "a 3 zone liquid cooled led high-brite lvds narrowscreen"
maybe this can be done with logic, but through hardware alone seems to be easiest..... I don't think I could design a logic board myself, nor do I think I need it at this point..... it may sound complicated, but it should be eazy hope I'm right
10-11-2005, 12:37 PM
our inverters will either have a 0-5V control line or a PWM in (or both).
I plan on making a basic system using an LDR and 2 pots. one will adjust the gain of the LDR and one will set the level allowing adjustment of the autodimming. it is just a theory at the moment but it shouldnt be too hard to achieve.
10-11-2005, 12:42 PM
that sounds like it should work too, just building a bridge like the last that I showed should do it.... I wouldn't expect there to be any draw on the 5v.... if theres any sort of load at all then you may not be able too, but otherwise it sounds like it should work
10-11-2005, 12:51 PM
no there wont be any draw. I am thinking some kind of simple circuit with a gain pot in parrallel with the LDR and then a level adjuster pot in series.
you then have a toggle to disable the LDR for full manual control and maybe have some sneaky relay trigger for a night mode from the HU wiring loom dim pin.
10-11-2005, 01:22 PM
sounds exactly like what I'm doing, mine is a 5v reference too..... I guess there exactly the same when you think about it, your inverters take care of the actual pwm, my supplys take care of varying the mw output from low to around 350mw at max
have you looked at any ldrs? are they avail. in different ranges & configs??
10-11-2005, 01:24 PM
that would be a no on the LDRs. as we only need to make a simple 5V signal i am not too worried. Everything else can be trimmed/bodged/tuned to match the LDRs
10-11-2005, 01:38 PM
Dude... How many computers do you have in your car?! Navigation on one screen, XP on another, and theres a third one (DVDPlayer?)
10-11-2005, 02:25 PM
that top screen is my rear view mainly... only one pc right now.......... gonna throw one in the rear for my kid I think soon though.... it may serve double duty as a self contained wireless hot spot router w/ my verizon broadband card to free up the only pcmcia slot I have on my front computer..... we'll see
10-12-2005, 11:04 PM
I got the third power supply... put it in & it's all good..... been playing with this, I don't think I will need to or want to do three seperate dimming zones.... it just better overall if it's evenly dimmed..... I played with trying to get the alpine screen & the pc screen to look as similar as possible.... a few screen shots