Just thought I’d share in case anyone runs into something similar (especially new-to-FastLED people like me).
I was playing with different code for the 12x12 WS2812B grid I built from strips when all of a sudden the top half stopped working. The LEDs were still lit up, but wouldn’t change as per instructions in the sketch.
My first thought was that I messed up the code – since that’s been the cause of all my previous problems. I double-checked the code and uploaded sketches that I knew worked, and still no change.
A visual inspection showed no broken connections.
When I removed power to the Arduino and returned power, no change.
When I removed power from the grid, and then returned power, all 144 LEDs would light up to match whatever point in the sketch the Arduino happened to be at, and then the top half would immediately lock up again.
I again, very carefully, inspected all my soldering – especially the spots between the working and non-working halves of the grid. Everything LOOKED clean… but I also realized I hadn’t REALLY cleaned the connections after soldering. Following a hunch, (after disconnecting power) I used small flat edge to carefully scrape between the connection pads on the strip, where the working and non-working halves met.
When I restarted everything, it worked like a charm again. I guess that there was just enough flux film to mess up the signal. Next step is to get some contact cleaner and make sure I clean ALL the soldered connections.
I have encountered similar problems. It appears some flux is corrosive enough to bubble up any solder it is sitting on and create shorts that are conductive enough to be a problem. I got myself some no clean flux and good chipquick solder and these issues went away.
I think I’m a little heavy-handed and over-generous with flux. Plus I’m using cheap stuff (I’d only be half surprised to find out someone repackaged some plumbing flux).
This has happened to me before when soldering on Arduino shields or building things on protoboard. Something wouldn’t work… clean the soldered areas… things work. Never any resoldering done or needed and never any future failures after the cleaning.
I try to make it a habit to do at least a quick toothbrushing with alcohol or circuit cleaning spray – but was too anxious to get things lit up this time.
In fact, if the build is only made up of solid state components, I’ve done a soap and water scrubbing and submersion and rinse in the sink. Just need to make sure you do a quick dry afterwards. Not something I plan on doing with WS2812’s though!
@allanGEE Well, that is very strange to me but I trust your observations… It is the first time that I hear about really conductive flux !!
I remember some problems with flux contamination but only with very high frequencies (in the Gigahertz range) where it did affect circuit behaviour but nothing like bridging out digital signals…
Try soldering something else with the same solder and flux mix and make sure you leave as much flux as you had before and let it harden. If you can actually measure resistance across it then you know that was it !!
Sounds like that’s worth a try! I also wonder if the flux could be holding some moisture? I’ve heard that dirty connections can become conductive in humid or damp conditions as the dirt absorbs moisture.
Regardless – everything works now, so I’m a happy camper!
I should probably look around for a higher grade of flux so I can STAY happy.
