ESP32 Not connecting to wifi when connected to LED strip

Hello community!

I am trying to get WS2812b LED strips going with WLED on a ESP32. When I just flash the board, everything is fine and dandy. But when I connect the board to the LED strip, WiFi is a no go… I have tried several boards/ strips, result is always the same.

Wifi is set to 2.4Ghz, dedicated SSID for SmartHome devices (only 3 devices connected) and WiFi channel is set static to 11, sleep is disabled (aka always on) and IP address is static.

Any ideas?


Do your LEDs light up orange? If they don’t light up or only the first few light up in white/green, your ESP is no longer booting and you might be running into this issue: FAQ - WLED Project
If that is the case, you can add a 3.3kOhm resistor between the 3.3v and D4 pins, or try a different LED pin.

Hey AirCoookie. The issue I have is that the ESP32 board goes offline as soon as I connect the data pin… When connected to the pc, it connects just fine. Everything working as intended. When I hookup data I am able to control the LEDs for a bit. But when connected ‘as they should’ with the LED strip, it falls offline.

I will try to connect a pull down resister in between and let you know how that goes. It’s the only thing to try… Does it need to be a 3.3K resistor?

I have a dedicated SSID on the router, fixed IP, WiFi not going to sleep, Channel on 11. All those trouble shooting steps have been executed without positive result.

It often means the power supply for the strip and the power supply for the ESP32 common lines are not connected together (bonded).


He said that, not pull-down. :wink:

@huggy-d1 : The ESP32 is fed from the LED strip. There are 2 sets of wires coming from the LED strip. One set with 3 (5V, data, Ground), that is what connects to my ESP32. And a set of 2 (5V & ground) that is connected to the power supply. Just to make sure: I measured the continuity, that is fine. That connection is from the factory, didn’t tinker with it at all.

@tonyno You’re right… My bat. Didn’t have 3.3K, so gobbled up a 3K by putting 3 1K in line, but that results in the LEDs not even turning on anymore.

Those pre-fabricated LED strip connectors are not guaranteed to be of good quality. Visually inspect and measure resistance from the pins to the solder tabs on the strips (if accessible). A small paper-clip inserted into the connectors is useful for making the connection. Sometimes a resistor shoved into the connector works. Measure between the resistor blob and the connector.

Pro Tip (for real):
Let’s say you have a long wire run and need to test for continuity (broken wire, bad connector), but you don’t have qualified help or expensive tools.
No worries. You can perform checks by yourself with ease.

Start by shoving a resistor so it touches 2 connector pins. Do this 2 times for 3-pin connectors, and 3 times for 4P connectors. Something like this:

──┼──█ 1 █─────┤R1├───┐
──┼──█ 2 █════════════╣
──┼──█ 3 █─────┤R2├───┘

Measure R1 and R2 and note the values.
Take the note (paper or electronic) with you to the other end of the wire or cable.

Measure from pins 1 to 3. Expect resistance value of R1 + R2
Measure from pins 1 to 2. Expect resistance value of R1
Measure from pins 2 to 3. Expect resistance value of R2
Unless there are problems with the cable or connectors, all measurements match expected values.

If you notice unstable readings while jiggling the connections, then the other end of the cable is probably not bad.
If the cable has multiple connection points, you can continue down the cable and repeat the procedure.

It goes pretty fast unless you forget to take the noted R1/R2 values with you…