Modular LED Build : Problem Help Needed

Other Hardware LEDs and Multiplexing
1

Dear Friends,
After many LED builds, i decided to do a modular LED build similar to that of the AI SOL. I havent copied their design :), just the concept.

Will upload images of my build shortly.

Well the basic is like this:

  1. 24 LED panel - consists of CW-6/RB-11/NW-2/Blues-5 arranged in a alternating fashion.
  2. Power from SMPS to LED panel
  3. Ardunio PWM Signal using Stereo Cable - got stereo jacks (This is the jack that i use http://www.flickr.com/photos/rgeorgi/4206781293/) on my panel where it can be plugged in.- use CAT 4101 4 Nos in each panel to control the 24 LEDs.

This is how the modular works:
have interconnected power jacks in each panel, so from one panel can attach a power cord to the second panel to light it up.
so does the Stereo jack...

Here comes the problem:

i currently have 4 panels completed and ran them seperately and all worked perfecto!!! was damn happy... then plugged one to another to make it a two panel combo and that too worked perfectly... now ... plugged on the third (used another SMPS power supply for this) but inter connected all the stereo jacks together in series... and boom the problem...
the first panel in which the Stereo Jack (will call it as SJ) from the Ardunio comes from works perfectly, the second one is also ok didnt see anything odd but the third panel, 12 LEDs start to flicker slightly not heavy but slightly... this panel was working perfectly when plugged in seperately ...
then plug in the fourth, the same problem of flickering LEDs only 12 flicker.

Thought 2 PWM pins were not able to control 4X4 (16) CAT's, so make another 2 PWMs from the Arduino and still the same problem... first two work perfectly when the 3rd and 4th are plugged in the flickering happens in the 3rd and 4th .. more vividly in the 4th...

1st and 2nd - SMPS#1, PWM 9 and 10
2nd and 3rd - SMPS#2, PWM 3 and 11

The only place where ther will be connection between the two sets, is at the GND from the Arduino, and input AC to the two SMPS...

Been having this headache for over 1 week... still not able to find a solution and have got about 25 frags that i wanna grown :slight_smile:

Kindly lemme know what might be the probable problem...

2

Lack of power supply decoupling.

3

where should there be de coupling? i have a 10uF at the 12V supply into the controller box, and from the box to the arduino i have another 10uF between the +&- as decoupler. or should there be a cap between the GND and + at the wire which i take to the LEDs'?

4

Mike thanks a ton.. it worked.. plugged in a 1uF decoupler at the +24v input of each panel.. and the flickering stopped and its works like a charm.

Thanks a lot again.