Please don’t think TLDR on this. Thank you.
I’m having a very similar problem and it seems hardware related but I don’t know what the solution is.
Background: I’m new to trying this stuff out but I worked as a developer for several years so I’m not a total stranger to microcontrollers, circuits and code.
I watched a few of Dr. ZZZs videos on YouTube and got very excited about using WLED to run some permanent lights on my house so I wrote down all the items he suggested and bought them and got everything set up on the floor to test before installation but I can’t get past the flashing LED problem.
Here is the set up I’ve been trying for about a month now and still have the flashing problems:
I have 12V WS2811 LED Strings. I’m using NodeMCU with WLED 0.10.2. I bought a bare metal 12 V 50 A power supply and I have an LM2596 connected from the power supply to the NodeMCU to drop the 12 V to 5 V so I don’t pop the NodeMCU. (I’ve actually tried both dropping it to 5V and to 3.3 V with the same flashing results). Also, all Grounds are tied together.
If I connect a single 50 Count LED string and turn the amps to around 250 mA sometimes I get the desired behavior but if I add more strings and turn up the amps to drive them, some of the effects work fine but when I try to just use Solid, the LEDs flash bright, then a bit dimmer, then dimmer still, then a bright flash of some random other color for a half a second or so, then they go back to the chosen color and randomly repeat the cycle. I’ve read some people have flashing problems every 20 minutes or a couple times an hour. My flashing is every few seconds.
The other day I grabbed an old X-10 power supply that I don’t use anymore whose label states 12 V and 200mA and wired it up to a single string to see if that would help. This gave me the desired results. When I choose a solid color it goes to that color and stays there with the current limiting setting at 250mA (the minimum it will allow, even though the walwart power supply only says it outputs 200mA) One thing to note, eventhough it says 12 V when I measure the Walwart output it’s actually 19 V but the 12 V LEDs don’t seem to mind. (I tested it on a sacrificial one first) I can use the little Walwart to power 2 or 3 strings and it sometimes does ok for a bit, but then if it’s all a solid color at too strong of a brightness it can pop the NodeMCU off and the lights just stay on however they were when the NodeMCU dropped out or they turn off too.
I’ve tied the grounds together, I’ve tried the sacrificial LED, I’ve turned off the current limiting seting and I always end up with the same results when I try to put more than one string in the line. I have spent quite a long time reading up on how to fix this and watching various YouTube videos from this great community, but I still have something wrong and don’t really know what to do to fix it.
The big difference I see from my setup compared to everyone’s samples is that most people use 5 V LEDs and if they are using 12 V LEDs in their demo they only ever show one string or strip running and the power supply is just a wall plug, not a bare metal one. As far as I can tell I’ve done everything people have said to do to solve the issue yet I keep seeing the same issue. I’ve even flashed the NodeMCU with older firmware versions to see if it’s the code but it seems the code is fine as is proven by using the walwart with just one string, but how can I fix this problem to make it is so I can do some longer runs?
My data line from the NodeMCU to the first LED is about 20 cm unless I use the sacrificial LED, then it’s about 3 cm. Either way I get the same results. I tried to look up the desired voltage to drive the LEDs and didn’t find the answer. The WS2811 datasheet says +6V to +7V is the voltage to the actual chip so obviously with the 12 V strings they are dropping it down a bit. I’ve read about using the levelshifter but I don’t understand why that would help when it’s the same as using the sacrificial LED, right?
If you’ve seen this problem as I’m describing it and can think of anything else please let me know. I’d love some guidance.