Car front lights controller

This page is kept for historical interest. It may document projects or methods that are obsolete and/or no longer relevant. The information here is not kept up-to-date.

This car has been scrapped.

Car with running lights

Car with high beam

Lights controller for high beams and fog lights on my Subaru. Uses an AVR ATtiny2313 microcontroller.

Details

This unit is used for controlling additional car headlights, such as high beams and fog/running lights. The module also controls a RGB LED on the dashboard, indicating the status of the lights and used as a alarm LED. It's connected directly to the cars battery, and sensing the status of the cars built-in park light, low beam and high beam.

Lights

Fog/running lights

The fog/running lights are controlled in such a way that they do not violate Norwegian law. Meaning; they can only be on during the day and must be used together with the parking lights. They can not be used together with low or high beam. Using the switch it's possible to still use the fog/running lights together with the low beam, but this is only permitted in extreme weather conditions or fog. The fog/running lights are turned or kept on for one minute after the car has been turned off, to illuminate the front of the car in dark situations. They also have a three second start up delay, so not to

High beam

The high beam is activated together with the cars build-in high beam lamps. If the fog/running lights are on they will be turned off, even if just using the headlamp flasher. The use of fog/running lights together with the high beam is according to Norwegian law only permitted when running at low speed (5-15 mph), but this combination is not possible.

I/O

Inputs

1. PD0 Parking lights
2. PD1 Low beam
3. PD2 High beam
4. PD3 Switch

Outputs

1. PB3 Green LED indication
2. PB4 Blue LED indication
3. PB5 Signal active
4. PB6 Fog/running lights
5. PB7 High beam

Wire connection

#	Color	Function
1	Red	13.8V +
2	Black	0V
3	Green	Parking lights in +
4	Brown	Parking lights in -
5	Yellow	Low beam in +
6	Gray	Low beam in -
7	Purple	High beam in +
8	White	High beam in -
9	Pink	Switch in +
10	Blue	Switch in -
11 & 12	Yellow (separate)	Relays fog/running lights and high beam out -
13	Red (separate)	Green LED indication
14	White (separate)	Blue LED indication
15	Yellow (separate)	Signal active

LED indication

A RBG LED is used for indication of which lights are active.

• Red High beams
• Green bright Running lights
• Green dimmed Fog lights
• Blue Alarm LED

Wire connection

#	Color	Function
1	Yellow	13.8V +
2	Brown	Red -
3	Green	Green -
4	White	Blue -

Source code

Bascom-AVR source is available in a git repository:
https://github.com/thomasjsn/AVR-Car-front-lights-controller

Gallery

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  PCB for vehicle light control

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  LED indication and switch

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  Switch for fog lights and low beam, and LED

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  System on/off switch

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  Unit mounted under the dashboard

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  Connection in the engine compartment

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  Relay and power, one relay inside the fuse box

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  Signals from the car lights

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  Car with high beam

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  Car with running lights

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  PCB with output extension

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Schematic drawing