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LED Tail Ring Light for your Car

Last Updated on by 56 Comments

The following article describes a fancy LED sequencing/diverging ring light circuit which can be used as a tail brake light  in cars. The idea was requested by one of the avid readers of this blog, Mr. Bobby. let's learn more.

Technical Specifications:

Hello,

I was just reading thru your wonderful article on building an LED chasing tail light:https://homemade-circuits.com/how-to-make-car-led-chasing-tail-light/

Could this circuit be adapted to create a round tail light that lights rings in sequence from the center out as the brake is pressed, one ring at a time until all the LEDs are lit and then flash all the LEDs twice and keep all LEDs lit solid after? If not, could you design a circuit that would?

I would be willing to pay for your time.
Thank you,

Bobby

The Design

The circuit diagram shown below has been designed as per the above request, let's understand its functioning with the following points:



IC1 which is a "serial shift resistor"  forms the heart of the entire circuit, the main function of this IC is to illuminate the LEDs connected to pin outs #3-4-5-6-10-11-12-13 in a sequence, keeping the sequence latched and illuminated as it proceeds. This happens in response to each clock pulse applied at pin#8 of the IC.

The LEDs which are triggered by the pin#3-4-5-6 and 10 are arranged as rings such that it illuminates from inner most ring first toward the outermost ring, producing an interesting and visually rich effect.

And that's not all, after the above effect the whole illuminated group of arrays flash  thrice and then shut off.

The above "show" repeats every time brakes are applied.

When brakes are applied, battery voltage connects with the circuit initiating the following operations:

C1 resets IC1 such that the sequence begins from pin#3 and not from any other in between pin out (this output illuminates the inner most ring).

IC2 is an oscillator IC which generates the required clocks for the IC1 from its pin#3.

In response to the above clocks, the sequence proceeds creating the desired diverging illumination effects, until it reaches pin#10.

The LEDs receive the required positive supply through T1 which stays triggered  due to the low logic at pin#13 of IC1

When the sequence reaches pin#10, T6 conducts which also switches ON T7.

The emitter of T6 is connected to pin#3 of IC2 which is already generating the clocks for the required of IC1.

The alternating low pulse from this pin out switches T6/T7 in a blinking mode.

T7, in response to the above blinking, sends correspondingly pulsating positive pulses to base of T1.

This in turn forces T1 to flash the LEDs in accordance with the above influence.

The illuminated ring arrays start flashing until the sequence is forwarded to pin#13.

The moment pin#13 becomes high, T1 switches OF and also the "high" reaches pin#11 of  IC2.

IC2 locks and stops the clocks at pin#3.

The whole operation freezes.

The above system breaks and repeats itself only as soon as the brakes are released and pressed afresh.

 

How to make LED Tail Ring Light Circuit for Cars and Vehicles

 

The LEDs which needs to be connected across the collectors of T1 and T2/T3/T4/T5 may be wired up in the following manner. The arrangement should be designed in a circular manner to form the corresponding RINGs.

 

 

Parts List

R1 = 2M2
R2 = TO BE EXPERIMENTED
R3 = 1M
R4---R12 = 2K2
T1 = 8550 or 2N2907
T2----T6 = BC547
T7 = BC557
D1 =1N4148
C1,C2 = 0.1uF
IC1 = 74LS164
IC2 = 4060
IC3 = 7812

ALL LEDS = RED 5MM, ASSOCIATED RESISTORS ARE ALL 150 OHMS, 1/4 WATT

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Comments

  1. "And that's not all, after the above effect the whole illuminated group of arrays flash thrice and then shut off.

    The above "show" repeats every time brakes are applied."

    Is it possible to have them stay on solid after the sequence as long as the brake is on?
    Thanks
    Jon

    Reply

  2. Hi Swagatam great work as always.
    Couple of questions you say:
    "Yes those are LEDs which indicate the tail light functioning and must be installed somewhere around the dashboard."
    Can the LEDS from IC1 pins 3,4,5,6 and 10 be replaced with a 1N4007 diode?
    Can this function as a solid lit tail light also?

    Reply

    • Thanks John,

      Yes they can be replaced with diodes but that won't lead to anything, if you want to eliminate the LEDs you can simply replace them with wire links….

      Reply

  6. Greetings!!!
    Hi Sir Swagatam do you have a simple digital speedometer circuit for motorcycle? may i get the link Sir? Thanks a lot!

    Reply

  8. Hi Swagatam,

    How can i make the LED's will be lit fast?
    what would i change?
    for now im using R2=1K

    Regards,
    Mike

    Reply

  9. sir swagatam,
    The electronics genius…the guru who speaks and electronics listens…
    Thanks for your wonderful contribution,to the world,may GOD almighty make you go bigger as you ENTER 2013…
    Yours loyal fan,
    Genetik

    Reply

    • Hey Genetik!

      Thank you so much! It's wonderful readers like you who keep me inspired to write more…

      It's my great pleasure to have you here.

      God bless you and may 2013 bring even more happiness to your life.

      Best Regards!

      Reply

  12. Hi Swagatam,

    Thanks for this circuit. it's working great but i have a little problem. it is slow to lit all the LED's. i used 1M pot for R2 to adjust it. what will i modify to make it faster?

    Regards,
    Mike

    Reply

  13. sir swagatam,
    Am just loving your blog, everyday more grease to your elbow..
    The above circuit has almost solve my problem due to it funtionality..
    I would be grateful if you can modify this circuit to be used directly from mains using transformer,that after the sequence of operation,it should be able to reset and continue the operation forever..
    Yours loving FaN…
    Sir genetik

    Reply

    • Thank you very much Genetik,

      Just remove the D1 wiring, and the circuit will repeat automatically forever.

      You can operate the circuit using any standard 12V DC transformer power supply or an smps adapter unit.

      Just connect the (+) of the power supply to the IN of IC3 and the (-) to ground of the circuit.

      Reply

  17. Thank you so much for your reply,
    how can i replace u2 with 7805 or any thing cheap
    and can i make this pwm ? if yes how ?
    thankx…

    Reply

  18. Hi Swagatam,

    i simulate this circuit in circuit wizard program. it was not running, i don't know what is wrong? the circuit diagram or the circuit wizard.

    Regards,

    Reply

  19. Hi,
    What is the function of the leds connected to the pins 3,4,5,6 and 10 of IC1? Are the part of the display of rings? The second diagram shows all the leds in the ring display, but what about those. Also, can you explain me the function of the diode D1?

    Reply

    • Those LEDs indicate the tail light functioning and must be installed somewhere around the dashboard.

      D1 is for latching the circuit once the sequence reaches pin#13 of IC1

      Reply

    • Hi'

      It will be difficult for me to troubleshoot the UPS problem, not sure why that's happening.

      The solar charger circuit is good, a 50 watt solar panel will be quite suitable with it.

      Reply

  21. Hi Swagatam,

    your blogsite is too busy. you have a lot of followers.
    keep up the good work and more power to you.

    Regards,
    Mike

    Reply

    • Turn signal lights should perform side-indicator kind of signalling, the above circuit is a decorative lighting so may be it's not suitable as side indicators.

      Reply

    • Thanks Thilanka,

      Yes those are LEDs which indicate the tail light functioning and must be installed somewhere around the dashboard.

      R10 is a mistake and it's not there.

      You had one more comment but that just vanished after I clicked "publish"……. might be due to some glitch.

      Reply

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