Assembling the control unit for daytime running lights

Daytime running lights control unit

Daytime Running Lights Control Unit-1 is designed to control daytime running lights for cars with manual transmission. More than 10 such control units were made and installed.

Logic of the device. The device will turn on the daytime running lights if: 1. the engine will be started; 2. the lights with parking lights will be turned off;

That is fully complies with the requirements to operation of the siren.

When the lights and dipped beam are on at night, the unit will turn off the low-beam headlights.

Daytime Running Lights (DRL) control circuit

The device connects: 1. DPM – oil pressure sensor (or “handbrake”); 2. +12 volts from the alternator or ignition switch (ie, where there is 12 volts when the car is running); 3. lights – to the plus contact of the lamps in any location on the car; 4. GND – car body; 5. lights – halogen or LED (for LED lights is slightly modified circuit).

Setting of the device is to check the algorithm of operation by applying simulation signals to the inputs of the device. The relay should turn off when +12 volt is fed to the input of the “hare lights”. The relay will be switched off if you short-circuit the DMU input to ground.

A photo of the ready made LED block:

The photo of ready made LEDs control unit

List of radio elements
Attached files:

ivan22ru Published: 22.07.2014 0 1

Reward I built it 0 1

Rate this article

  • Technical Literacy

Average score of the article: 4.1 Voted by: 1 person.

Comments (25) | I built it ( 0 )| subscribe

Registration is required to add your build


What happens if the driver turns on his lights during the day? The running lights go out – you get a penalty! You should tie control of low and high beams to running lights, not to parking lights.


What is the need in running lights during daytime? This scheme was invented in order to use the car during the day not to bother with all sorts of tumblers, buttons and so on. When it gets dark, you turn on the lights and the lights are off. Rules. Section 19. Paragraph 19.5.- In the daylight hours on all moving vehicles in order to identify them should turn on dipped beam headlights or daytime running lights.


In any position of the buttons, toggle switches should something light that did not fined traffic cops. Forgot to turn off the lights, daytime running lights are not lit, and that’s caught on the trap. About the circuit: VT6 KT503 transistor is too weak to control relay. I recommend you put KT815, KT817. The elements VD1, VD4, R4, R5 are superfluous in the circuit. Resistor R2 must be shunted with capacitor 10…100 mk so as not to let noise from ignition unit to input of device. On the power supply you also need to install a blocking capacitor 100 microns.

Noise and vibration isolation for Nissan Teana doors.


Well, if you do not understand what the author, then there is no need to write. The author made everything correctly, all the rules are taken into account.



The scheme is good. But a better scheme with automatic switching on your headlights when your car is running, I made such a circuit, works on 5 + and no need to throw additional wires.


With increasing voltage – a good option, but you need to make, to turn on dipped beam when the generator fails.


Eugene, good day! Do you still have the scheme of connecting the low beam headlights only to the battery and an additional output to reduce the brightness when the dipped beam is on?


Interesting idea – engine detection by oil pressure (5+). True, when the engine starts poorly (with long cranking) the oil pressure warning light goes out. Maybe try a battery charge signal?


The article says that the circuit for the LED lights is different. So what can be changed there, because the power supply circuit for the sidelights goes through a relay?



I collect this device exactly for the LED running lights, and collect it on a relay, I think it will not stop working.


Repeated device. The problem is that when I start the LEDs are blinking at half light. The engine is started, they light up as they should. How to remove this effect? Or is it supposed to be?


Maybe I do not understand something, but why start a garden? All trivially simple, without any problems and blinks, the connection scheme will repeat any motorist and without any cards and parts and soldering. Who is interested, see the wiring diagram. You have to buy only one relay. And one more thing! If you watched my connection to the lights, the scheme shows that you can connect and halogen, switching relay for cars designed for a current of 30A, the car started – lights turned on, lights turned on – lights turned off! All simple, put on ten cars, works without any problems! Personally, my car powered from the ignition coil (for me, it was optimal for the wires) turned the ignition on the ignition coil and then power came from there, like I wrote so I think you understood!

Catwalks for additional instruments with my own hands


For sergius68 explain why this is happening: the battery has a voltage of 12-13, 2 volts, as luck would have it, when you start the car starter takes the current and the battery voltage drops to 9-10 volts, this voltage drop and is displayed on the LED flashing at half load, it is normal! Well, if it bothers you so much, then put a voltage regulator for your LEDs, the scheme give but it is particularly necessary and do not! LEDs are controlled by current, and virtually all LEDs are built in current quenching resistors


Thanks for the examples, but I am interested in this particular circuit. When I start my car, for some reason, the relay is triggered and the LEDs are blinking. In theory the relay is not supposed to be triggered. This is what is bothering me a bit. Home-made 6 LEDs at 12 volt 1.5 watts “Eagle Eye”.


Ivan, if you can then describe in detail the circuit and the element base for connecting a LEDs with a voltage regulator LM 2576 adj with a stable output to the diode lights 12 volts


Figure out the resistors: from top to bottom 10kOhm 5.1kOhm right to left 5.1kOhm 1kOhm 1kOhm What kind of transistors are on this board? They are KT503A, why do they look different?



Assembled the circuit – does not work (picture posted, can you advise). Spread out as I have it all is maybe not right. kt503e, the fuse is under the board glass


I want to build a simple circuit to control the lighting, but I do not want to mess with relays. Tell me, Ivan, if the power of the lights 4W each, then, as I understand it, the current through the transistor VT6 will not exceed 0.6A, therefore you can apply a transistor with a collector current of 1A and remove the relay from the circuit. Or it is not so?

Trisistor ignition block diagram


Do you have a scheme so that the parking lights would light up from the parking lights, and when you turn on the turn signal, they would blink in sync with the turn signal?


If the car’s parking lights use incandescent bulbs (not LED), it is easy to connect the parking lights without using additional “control units”. Here’s what to do: 1. “Minus” lights connect to “plus” lamps “clearance” (under the hood you need to find the plus wire of any of the lights “clearance” and connect to it. When the lamps are not powered, their “plus” wires are connected to the “ground” of the car through the spirals of the “clearance” lamps. 2. 2. The “plus” of the lights is connected to the “plus” at the input of the heater fan mode switch (the wire from the lights must be led into the cabin through the bulkhead), or to the “plus” of the wiper control circuit, or to any other wire, “plus” to which is supplied only after turning the key in the ignition switch.

As soon as the ignition key is turned, the “plus” from the battery through the ignition switch and the corresponding wires will be supplied to the corresponding input of the DSP. And the “minus” of the lights is connected to the “ground” through the spirals of the lamps of “clearance lamps” at any time when the “clearance lamps” are not on. So, the parking lights come on as soon as the key is turned in the ignition switch. If the driver turns on the “lights”, the “minus” of the lights will be “plus” power, and the lights will go out (because there will be no potential difference at the inputs of the lights).

As a result, the behavior of the lights is the following: – you turn the key in the lock – the lights come on; – you press the button of parking lights – the lights go off; – you turn off the lights – the lights come on; – you turn off the ignition – the lights go off.


Sorry, even a diode is not needed, I used it for a different algorithm. Power to the fog lights from the lock is interrupted by a closed relay, paralleled to the dipped beam. That is all!

Re-polarization and short circuit protection for battery charger

A simple controller for the headlights without microcontrollers. Tested in the harsh conditions of the Yakut winter

Greetings fellow Datagorians! I want to tell you a story of how I made controllers for exhaust systems (daytime running lights controllers for cars). Traffic Police, as always at the request of the workers, forced us to use the parking lights in cars, and we are law-abiding have happily complied with the instructions. The first problem was not long in coming – we forget to turn off our DRLs and have dead batteries, being late for work and kind words and thoughts about our dear traffic police.

Gentlemen and ladies, fellow car owners, we have a new kit with modifications and on the factory circuit board: Project-013 “DRL CONTROLLER”. Car siren controller for parking lights Catch up!


Comrade, consider the datagoric recommendations

Tested and useful hardware, you may use it.

Tested in editorial lab or by readers.

↑ I made my first LED controller with a relay

My van had very funny fog lights, they are plastic, white and use a parking light! They weren’t any use at all – had to be rebuilt! Dimmer bulbs were replaced by LED counterparts, it allowed to disregard current consumption. Then I changed the circuit, thanks to the availability of wires in my minibus is great. In an hour with a bite was assembled and connected the circuit:

I got the clearance signal directly from the backlight button. The result: the correct operation of the lights, switching off when the lights are on and the inability to forget to turn off the lights. This scheme works for several years without complaints, both mine and traffic police inspectors.

But here, I bought a second car for the family. Big, comfortable and… terribly inconvenient in terms of laying new wiring. As I said, in fact, I am lazy person, too lazy to disassemble the dashboard, pull through a tight corrugated wire, and then collect it all back! No, please! I need another solution!

↑ ATmega8 variant.

The headlights were bought separately for the same price, they were assembled easily, with 2 tapping screws in the bumper. The thing about the controller: as usual, in my usual way, assembled the circuit on the spot for an hour. I used ATmega8, because I needed an additional feature for indication of the LEDs work, which was turned off when the car was running. The principle was the following: the car is turned off – battery voltage is less than 13.5 V. Started the car – charging, the voltage is higher than 13.5 V, the running lights turn on. Of the connections 2 wires to the battery and 2 wires to the running lights. I did not start the signal from the lights – lights are very harmonious with the exterior of the car.

Microcircuit TDA7388 for amplifier installation

I decided to make a controller for my friend, but since the design was supposed to be almost free (thanks, I’ll never forget it!), microcontroller is too much! And why, there is a simpler solution – a comparator!

↑ A simple solution – a schematic of a LM358 comparator based warning light controller

As a comparator, I used an Opu LM358, very cheap and no need for a voltage regulator, power the LM358 up to 30 volts, again saving! The scheme below is very simple and clear, the standard connection diagram of Opus as a comparator with a reference voltage source.

Attached the entire circuit directly to the wire battery with a plastic clamp. Minus circuit – no function to turn off the low-emitting headlights when parking lights are on (I was too lazy to introduce). And then it started… My friend bragged about the device to his friend. I got a few more suggestions for making controllers. What did the car enthusiasts liked? Simplicity of installation and no need to drag wires into the salon, everything is located in the engine compartment! The design ended up being simplified by 2 more resistors, which benefited my lazy ego. Instead of adjusting the reference voltage, I introduced direct adjustment of the measured voltage:

Adjustment of both options boils down to setting the circuit threshold for triggering when the alternator is running, i.e. when the on-board voltage is above 13.5 V

The design has not changed, all assembled very quickly, work is reliable even in our Yakutian cold weather.

I assembled this version of the device, as well as the previous ones, on the spot in 10 minutes. I used Chinese breadboard, covered ready construction with hot melt adhesive and refined with heat shrink.

( No ratings yet )
Like this post? Please share to your friends:
Leave a Reply

;-) :| :x :twisted: :smile: :shock: :sad: :roll: :razz: :oops: :o :mrgreen: :lol: :idea: :grin: :evil: :cry: :cool: :arrow: :???: :?: :!: