sequential led circuit help

[zbomb5610]

So im not great with circuits or design. Im trying to set this up for my wifes car on her turn signals. I want leds to start at one end and then continue through but stay on as the next one lights up and then reset.

I was looking at the following circuit designs and also the way the guy did it in the youtube video. He used transistors for every led though and im not sure which parts or values I should be using.

I guess if I can get help with a circuit design that would do this I would greatly appreciate it.

https://m.youtube.com/watch?index=32&list=UU4Fdl1eB5OEyp6CWVuJcuZQ&v=tosZZrQfDlc

https://www.brighthubengineering.co...w-to-build-a-simple-led-light-chaser-circuit/

 

[crutschow]

Will these lights also be the brake lights?

 

[audioguru]

A Ford Mustang has rear lights like that.
A chaser circuit is different because a CD4017 IC produces only one output at a time, in sequence.

An LM3914 is a bar graph driver IC for up to 10 LEDs. If it is set for a bar, not a dot and its input is a linear ramp then it will do what you want. The "clicker" can momentarily discharge the capacitor that is charged by a transistor constant current source.

 

[zbomb5610]

So this would just be for about 8 leds in the front corner markers that will just go off when the turn signal is on. They wont always be on and then go through the sequence rather only do it when the blinker is on. So 8 amber leds that light up one at a time but stay on as they move to the end and then reset.

Not connected to brake lights.

 

[zbomb5610]

The guy from the youtube video stated he used a 4017 and a 555.

https://au.toyotaownersclub.com/forums/topic/43790-sequential-led-blinkers-switchback-drl-mod/

But he doesnt show his circuit design or how he has all of his transistors setup

Is there an easier method or can someone just write a circuit on what he probably did?

 

[audioguru]

I found some circuits in google Images when I searched for Sequential Turn Signals Circuit.
One circuit used SCRs triggered from the outputs of a CD4017, and a transistor is used to turn them all off.

 

[zbomb5610]

I found some circuits in google Images when I searched for Sequential Turn Signals Circuit.
One circuit used SCRs triggered from the outputs of a CD4017, and a transistor is used to turn them all off.

So I saw this circuit from google images

https://www.circuitstoday.com/automobile-turn-signal-circuit

does that seem like what the guy in the video probably did? And where it says R5 through R8 does that indicate pairs of lights turning on so would I just use one for each led and one BC547 per led?

thanks

 

[audioguru]

No.
You found a chaser circuit that has only one LED lighted at a time. You want the first LED to light then stay lighted when the second LED lights. Then both LEDs stay lighted when the third LED lights etc. SCRs will do that, not ordinary transistors.
R5 to R8 limit the base current of the transistors so that their base-emitter diode does not short the outputs of the CD4017. One of each pair of LEDs is blinked when switch S1 is set to Left or Right.

 

[zbomb5610]

No.
You found a chaser circuit that has only one LED lighted at a time. You want the first LED to light then stay lighted when the second LED lights. Then both LEDs stay lighted when the third LED lights etc. SCRs will do that, not ordinary transistors.
R5 to R8 limit the base current of the transistors so that their base-emitter diode does not short the outputs of the CD4017. One of each pair of LEDs is blinked when switch S1 is set to Left or Right.

Ok, I see what you are saying. I found this and this seems like what I would probably need. I will read more into it and if i have questions I will get back to you.

**broken link removed**

Thank you so much.

 

[audioguru]

That circuit should work well except a modern car does not have a -12V terminal (old British cars used a positive ground because they drive on the wrong side of the road). A modern car has +12V and 0V.
Any little SCR will work.

 

[eTech]

So this would just be for about 8 leds in the front corner markers that will just go off when the turn signal is on. They wont always be on and then go through the sequence rather only do it when the blinker is on. So 8 amber leds that light up one at a time but stay on as they move to the end and then reset.

Not connected to brake lights.

Hi

So these would replace front turn lights? or clearance lights?

eT

 

[zbomb5610]

Hi

So these would replace front turn lights? or clearance lights?

eT

well there are already turn signal ambers that is just 1 bulb in the headlights, this would be 6 leds in the corner marker on the corner of the bumper which would go in the sequence mentioned along with the single amber bulb of the headlight. So they would only be on when the turn signal is on.

and instead of the -12v that would just be my ground then correct?

 

[crutschow]

...............................

and instead of the -12v that would just be my ground then correct?

That is correct. The battery -12V connection is the car ground (chassis).

 

[EinarA]

If you use SCRs, you will have to cut power to them to get them to turn off. A simpler circuit would use a shift register. You would clock in a high input and connect the last output to the reset pin, which would turn off all the outputs at once. Then the cycle would repeat. You might even be able to drive the LEDs directly, but most likely transitors would be needed.

 

[alec_t]

We don't know which country you're in, but make sure that what you are proposing to do doesn't conflict with Vehicle Regulations or invalidate your insurance.

 

[audioguru]

If you use SCRs, you will have to cut power to them to get them to turn off.

The PNP transistor cuts power to the SCR's during the reset.

A simpler circuit would use a shift register.

Yes, but a circuit already designed does not appear in Google Images. The SCR circuit is shown instead.

 

[crutschow]

If you use SCRs, you will have to cut power to them to get them to turn off. A simpler circuit would use a shift register. You would clock in a high input and connect the last output to the reset pin, which would turn off all the outputs at once. Then the cycle would repeat. You might even be able to drive the LEDs directly, but most likely transitors would be needed.

The SCRs eliminate the need for any transistors so it's sort of a wash between the two circuits (assuming transistor drivers are needed).

 

[zbomb5610]

Thanks for all the help guys, I have a bunch of random stuff coming in so I will play around with a few circuits and I will post up my results. Going to be working with a switchback design as well so hopefully it all goes smoothly.