LED Chaser 3 x 36

[Shadofax]

Hello... I need help.

I am an amateur in electronics. I'm hoping someone out there has a circuit design that I can use. I have a PCB with 108 x 3000cp LED's arranged in 3 circles - each containing 36 LED's. I wish to apply a 'chaser' circuit to each ring such that when activated, the first LED (at 12 o'clock on the circle) will illuminate - then switch off - then the next will illuminate - then switch off.... in rapid succession all the way around the circle, then continue until turned off.

Further, the first LED (at 12 o'clock on the circle) of EACH ring of LED's should illuminate at the same time such that the illumination chaser effect of each ring is in synchro with the others. I have attached a PDF file showing the layout of the existing PCB with the 108 LEDs affixed.

I have searched high and low at electronics shops etc. and the best I can find is a circuit that is an LED chaser circuit for only 8 LED's - with no way of linking three rings of 36 LEDs together in synchro.

Can anyone help?

Many thanx. :D

3_x_36_LED_Chaser_PCB_Diagram.pdf

[audioguru]

Hi Shadowfax,
Welcome to our forum.
I have posted two chaser projects, but each uses only 10 LEDs.
If you planned your LED's PCB for it, it would have been easy to sync the circles simply by wiring the LEDs in series. Then an LED at any position would be connected to the same LEDs in the other circles. You would need only 36 drivers instead of the 108 drivers that you need with your existing wiring.

"4XXX series" ordinary Cmos ICs can directly drive the LEDs and provide about 10mA to 15mA with a 12V power supply. If more current is needed, individual output transistors are required.
"74HCXXX series" high-speed Cmos ICs can provide 25mA and their power supply is limited to 6V or 7V max.
1) 74C154 (or 74HC154) data distributor ICs have 16 outputs. They can be cascaded for 36 outputs and driven from a binary counter.
2) 4017 (or 74HC4017) decade counter/decoder ICs have 10 outputs and can be cascaded for 36 outputs. They need just a simple clock oscillator.
Counters that are listed above can be sync'd by resetting them during power-up, or any time.

[Shadofax]

Hello Audioguru... and thank you.

A couple of things:
1. Forgive my ignorance... but when you say "I have posted"... I assume that means that I can view them somewhere. Where do I view postings?

2. You make a good point about wiring in series... I hadn't thought of it. Would this not still be possible by modifying the existing wiring?

Many thanx.

[audioguru]

Hi Shado,
OOps, I'm sorry that I called you a shadow before.
1) At the top of this page are category buttons for Home, Projects, Articles etc. On the Home page, my latest (posted just a few days ago) chaser project is highlighted as an article. Down the right side are the newest projects, and my earlier "3V LED Chaser" project is linked. All projects can be seen with the Projects button at the top of this page.
2) The "same LEDs in each circle" can be wired in series on your PCB by connecting them horizontally, since the circles are side-by-side.
You can't directly drive series-connected 3.5V blue, green or white LEDs from high-speed Cmos because the supply voltage would be too low. Ordinary Cmos would probably need a 15V supply.

Are you having a nice summer down-under, while I'm freezing up here? ;D

G'day, mate!

[MP]

Looking up your previous posts is not going to show him how to make a 36 LED chaser. I am guessing cascading 4017s or making a twisted ring counter with JK flip flops is probably more of what he is looking for.

MP

[audioguru]

1) 74C154 (or 74HC154) data distributor ICs have 16 outputs. They can be cascaded for 36 outputs and driven from a binary counter.
2) 4017 (or 74HC4017) decade counter/decoder ICs have 10 outputs and can be cascaded for 36 outputs. They need just a simple clock oscillator.

I gave him these 2 suggestions for what he is looking for.