circuit to control halo

Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=114198
Printed Date: May 14, 2024 at 2:18 AM

Topic: circuit to control halo

Posted By: stupidpig
Subject: circuit to control halo
Date Posted: June 03, 2009 at 2:49 PM

I'm planning to have the following setup for my headlight:

- 2 halo for each headlight, one for low beam and one for high beam.
- Each halo is powered by two 3W prolight star, one white and one amber.
- Both LED should turned on when DRL is active (so brightest halo during day time and having kind of yellow color).
- White LED turned on when park light is on (so dimmer white halo during night time).
- When turn signal light on, only the Amber LED turned on, so the halo will be flashing in amber during turn. I want the white to be turned off too for this case (so only amber color for both day and night).
- It will be great if the transisiton between White and Amber (normal halo and turn signal mode) can be fading in/out, but that's optional.

So, basically the combination between inputs and outputs will be like this (D = DRL input, P = Park input, T = Turn signal input, W = White LED output, A = Amber LED output):
D P T | W A
0 0 0 | 0 0
1 0 0 | 1 1
0 1 0 | 1 0
1 1 0 | 1 1 (won't happen)
0 0 1 | 0 1
1 0 1 | 0 1
0 1 1 | 0 1
1 1 1 | 0 1 (won't happen)

The 3W prolight is running pretty hot at 700ma each, so I will mount all LEDs outside the headlight housing (underside), with big heatsink attached to them. I already spiced the turn and park bulb wire (12v), and I think I can use a relay NC line to get the DRL (7.6v) from the high beam, since relay triggered at 8.5V. i probably will need to drive those LED with a direct power from battery via relay since there are total 8 such LED (total current will be 5.6A), and probably too much to get the power from the 3 inputs.

Any suggestion on how should the circuit looks like? Thanks.

Replies:

Posted By: stupidpig
Date Posted: June 03, 2009 at 3:40 PM

I just think that if I don't need the fade in/out, simple logic gates may work. (T = Turn, D = DRL, P = Park)
Amber = T or D
White = (D or P) and (not T)

I'm noob in electronic, can someone tell me what IC I should use? T and P is 12v, and D will be 7.6v. Output to Amber and White each has to be able to drive two Prolight 3W LED in serial (White Vf 3.5v, Amber Vf is 2.2, both 700ma).

Thanks.

Posted By: stupidpig
Date Posted: June 03, 2009 at 6:22 PM

i do more reading and found the the logic part I just need 4 x 2-input NOR gates to handle it. I tried to found Quad 2-input NOR gate IC but can't found any to work with 12v (all of them running 5v). Can someone point me to the correct direction? Thanks.

Posted By: tj.poorman
Date Posted: June 04, 2009 at 6:29 PM

What vehicle?

Posted By: stupidpig
Date Posted: June 04, 2009 at 7:38 PM

Well, I don't think it is vechicle specific, but anyway, mine is 09 civic sedan, and I'm working on an aftermarket headlight.

Since I can't found any logic gates work on 12v, I think most likely I will just use 3 x 5v voltage regulator to drop the 3 input signals to 5v, then pump them into a 7402 NOR gates, then take two outputs to trigger some high current LED drivers. Still hoping someone can help me to find some 12v NOR gates to simplify it tho.

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