Help needed debugging interactive LED display

[glennkachmar]

I am 6 panels in to an 8 panel interactive LED display. I am also a newbie at this. Until Monday, I didn’t know how to solder. Two of my six panels have an arrangement of 5 lights (trapezoidal pattern) that stay lit up and do not interact in any way. I haven’t been able to find the problem. Any ideas?

I also have an unrelated question. Is there an easy way to add music to the device so that when the lights are going, music is automatically triggered?

Thanks in advance to anyone who might answer.

G

[Windell Oskay]

> Two of my six panels have an arrangement of 5 lights (trapezoidal pattern) that stay lit up and do not interact in any way. I haven’t been able to find the problem. Any ideas?

One panel at a time: Are those 5 LEDs on full bright, or only a little bit? And, how are the other 10 LEDs in that quadrant acting?

First thing to double check is that each LED in that half-quadrant is oriented correctly (check the LED “collars” to make sure that the flats all point the same way) and that each LED in the quadrant is correctly soldered. Check each solder joint to make sure that they look shiny and clean.

> Is there an easy way to add music to the device so that when the lights are going, music is automatically triggered?

There are a few different ways if you know some electronics, but I’m not sure what you regard as “easy” — you could sense and divide the output signal from each node, but then you also need to figure out what kind of device you plan to drive from that output.

[glennkachmar]

Those five LEDs are fully bright and the others are acting normally. I will check the orientation. I didn’t realize there was a way to do this once the leads were clipped.

I don’t know much about electronics, so the music idea may be a huge challenge. Likely is.

[glennkachmar]

I was wrong. Five of the other LED’s in the quadrant of the panel I mentioned are off (the other five in the top half of that quadrant). All of the LEDs in the bottom half of that quadrant work fine. But I had two panels doing with the five bright lights thing and now it is just one. So that is good.

I have another panel that has so many issues, I’ve signed it up for group therapy. I will be checking that one later. And another with a few issues. But I’d just like six working panels right now, so I’ll be happy if I solve the issues with the one panel.

[glennkachmar]

OK, solved that one panel. Now I may debug the others a little.

Funny story: I wanted to check the LED collars as you suggested, but didn’t know what these are. So I googled “LED collars.” I don’t have a dog, but if I ever want to know what I need to walk one at night, I now have the answer. It brought me no closer to the solution though (but I figured it out).

The issue was some of the points where I soldered the leads – some were barely soldered in and one or two were black.

Thanks, by the way, for the help.

[Windell Oskay]

> The other LED’s in the quadrant of the panel I mentioned are off. 

Then, there are (at least) two independent problems here.  

Problem 1:  The LEDs are not responsive, stuck in one “direction”

Problem 2:  The LEDs in the other half of the quadrant are all off.

There is no single place on the circuit that a single problem could cause both of these to happen.  First, then, try to figure out why the other quadrant is fully off.  It’s likely a soldering problem.

[Windell Oskay]

Ah– bad timing for my reply!

On the next panel, see if you can identify any similar types of soldering issues– they’re responsible for a good 90% of things that ever go wrong. :)

[glennkachmar]

I’ve got 7 out of 8 panels running perfectly. The 8th will have some issues. I had a blocked hole for the diode and struggled to get the diode through it. Tried a lot of different things to unblock the hole. I also had to use a resistor that I had accidentally put in to a practice board (I started using the Evil Mad Science ones by accident. I later had to remove it from the practice board and use it for the 8th panel as I ran out). So that last panel has some work on it before it wil be working.

But the most important thing to point out is that your suggestions have given me the confidence I needed to debug the panels. I fixed 2 based on your advice. Thanks a million.

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