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Simple 18 LED Chaser Needed For A Lighthouse Answered

Hi, I have built a couple of different 10 LED chasers in the past, but I need one with 18 super bright white LEDs for a lighthouse being built at my dad's Church for VBS next week. I don't have a lot of time to order parts and the area I live in is very rural so I don't have a local retail outlet.

I do have a 555 and a couple of 4017 chips so I should be good with that. I have a good selection of resistors and capacitors. I don't  have access to a lot of diodes. I can work with voltages from 3V to 12V without any problem.

So I'm really looking for a schematic using a 555 IC, two 4017 ICs and no diodes.

Any help would be great.



Best Answer 6 years ago

Maybe you saw my lighthouse


Yes I did. It's very nice. Could you explain how to add another 4017 to support 18 LEDs. The lighthouse is going to be around 9 foot. I don't feel that 8 or 9 LEDs will create the proper illusion of movement.

My component level designing and modifying is limited. I generally work with drives, relays, transformers, sensors, etc.

Hey iceng, is there a way to speed yours up a bit. I know that the pot is used for that, but I was wondering if different resistor values would change the pulse rate that is adjusted by the pot.

Change C1 to 1uF for a ten times speed up or 4.7 uF for a 5X speed up/


Thanks for the quick replay.

I ended up using this one with a couple of changes. I attached a second LED in series to each of the eight you have listed in the schematic. I then changed the R3 resistor to reflect the new LED layout. A toggle switch was also added to turn the circuit on and off. I mounted my finished lamp in the lighthouse last night and everything works.


Answer 5 years ago

I tripled the size.  Hope that is more visible for all.

This is for all the misinformation about my Original circuit here....
  • The circuit uses no steering diodes.
  • Two LEDs are always ON at any one time.
  • The other 16 LEDs are off.
  • One LED advances on a Rising 555 pulse.
  • Another LED advances on a Falling 555 pulse.
  • The transistors let you put TWO or Three LEDs in series.
  • The LED current can be more then the 4017 can deliver.
  • You can reduce the 240 ohm to increase the brightness.
  • Minnesota has Radio Shack has LEDs...

I'm not sure what i am doing wrong, i have built this circuit 3 times and every time when i plug in the leds they just all come on and stay on at the same time. I cant figure it out.


6 years ago

Here is a cool circuit  for 18 LEDs for a light house running by twos...

that means l1 l2 on l1 off l2 l3 on l2 off l3 l4 on etc

This lighting is more conducive to lighthouse simulation..



Ok i like this circuit but it isnt quite enough, i want to use this but i need more than just 1 led off each of the outputs, i was thinking of a 6 in series off each leg of the 4017's will i need to use any different components to have that many LED's off each one? It just isnt bright enough in the light house with 1 led, mine is about 11 feet tall and the light it is replacing quit and i thought i would replace it with LEDS, i love this idea since there is nothing mechanical to break like my last one where the mirror that rotated to shine the light quit working. They wanted almost 100 dollars for a new one and this will last for a really long time omred to that. Or maybe i just have some bad LEDS, if you know of a good bright one i could mybe use that but i think it will still need more than one

Thanks for your help

I assume you are using white LEDs that require 2.5 to 3 volts each.
That means you can only use 3 in series about 9V ..
Most of remaining voltage gets used up by the transistor and IC output
this needs measurement.
So you have to experiment using a current meter with the series resistor.
The start values of resistance at 100, 82, 64, 56, 47, 33, 25, 16, 10 ohms.

If you want more LEDs ask your question and we can supply a circuit of
parallel drive.


o you have a bigger drawing or a pinout of the 18 led diagram. I am trying to tell which pins are wired together and which arent but i am having a hard time trying to read the small diagram. I tried blowing it up the diagram but it made it even harder to read. Thanks

Ok i guess i will need to do it in parallel it is, i just cant get enough light from only 3 leds unless you know of a different led that would be really bright. Do yyou know of a circuit i could do this in parallel with.

For this to advance smoothly the 555 output on pin 3 it needs to be a
balanced sq wave ( same time high as low )...

If this works for you don't forget to click ot best answer..

This circuit, titled "18 Stage LED Sequencer"
kind of looks like it could maybe be made to work for you. Not sure how much brightness you need for each LED.  If you want more than 5mA or so per LED, then things are going to get more complicated.

Also I know you said no diodes, but those (4) diodes that are there are just being used to make some AND logic.  If you have some actual AND gates or NAND gates, you could of course use those.

But seriously, diodes are not hard to find.  Even if no stores exist where you live, you can find diodes in junk.  Or maybe even substitute low forward voltage (like red) LEDs in place of whatever it was, 1n914, and that would probably work too.

It does need to be fairly bright so that it can be seen. The light house is going to be about 9' tall. I've been looking for some diodes here at work in some old drives but haven't had much luck so far.

I found a bunch of 1N4407 and a few 1N4744. I know that they are for much higher voltages, so what would be their effect on this circuit. I'm trying to locate some 1N914.

A 1N914 DIODE PDF is useful because of a low forward voltage.
A 1N4148 Diode also low fwd voltage..  Or
A more recent Schottky 1N5817 diode with a lower forward voltage.


My brother who lives in Greensboro, NC is coming home today. I asked him if on his way to stop by a Radio Shack and pick me up some 1N914 diodes, he said he had 10 at the house that he would bring them. So, I guess that solves my diode problem.

These are the LEDs I have http://www.parts-express.com/pe/showdetl.cfm?Partnumber=073-022&FTR=super%20bright%20white%205mm%20led%2017000%20mcd%20kit%20100%20pcs

Specifications: • Size: 5 mm • Lens color: Water clear • Forward current: 20 mA continuous, 50 mA peak • Forward voltage: 3.0 to 3.2 VDC • Viewing angle: 5° to 25° • Luminous intensity: 17000 mcd.

I've noticed that they can handle 4x the mA delivered in this circuit. So is there a way to beef it up a bit?

I tried to build this one but after two attempts, something was not going right with it. I feel that it was me making a mistake somewhere during the build but I didn't see what it was. Now that I have time, I'll try it again.

I think the most likely place where you could find some honest rectifier diodes is inside the driver circuit for one of those compact fluorescent light (CFL) bulbs, and it seems like everyone has those darned things now.

Also if you happen to have any of the old style AC-to-DC adapters, the kind with a transformer in them, these also have some (typically 2 or 4) rectifier diodes, assuming the output from this adapter is DC.

Regarding the diodes you found:
1N4407 is a zener diode with a reverse breakdown of 13V.
1N4744 is a zener diode with a reverse breakdown of 15V.
These are zener diodes.

I think those would work, provided that the supply voltage is never higher than their reverse breakdown voltages, 13V, or 15V, respectively.

The 4017 can be cascaded so all you need is 2 4017, a 555 to trigger them and a few additional components.

4017 cct are all over the place.

This is just what you need


Thank you. That is the same schematic that Jack proposed yesterday. I have the 555 and 4017s and now diodes.

Ah yes I didn't notice until after I had posted. But it will work.