Why Does ESP32 Burn Out When Connecting WS2811 12V LED Strip Directly to GPIO?

elktrod wrote:

(...) wdzam... The method of swapping strips, power supplies or individual components always works better than a single meter when you lack the funds for another meter or can't verify the measurements with another method.... With that said, such methods can also be costly, as it's a shame to stoke up another ESP32? @ElectrodBot

Preliminary assessment of available information .
From the wording of your question, it appears that you are facing several significant problems:
- Uncertainty about the type and number of GNDs on the ESP32 module.
- Suspicions related to the incorrect voltage supplying the circuit (possibly due to the LM2596 regulator).
- Concerns about the correct GND connection between the ESP32 and the WS2811 diode driver, especially when using 12 V and 5 V power supplies.
- Repeated instances of ESP32 modules being damaged (stoned).

The information presented suggests that it will be crucial to re-verify all voltages and check that the grounds are indeed correctly connected together.

Direct answer to the question .
1. all GND pins on the ESP32 are the same ground. Although there may be several pins labelled as GND, internally they are connected and provide a common reference point.
2. the ESP32 is most often supplied with 3.3 V (max. 3.6 V according to the datasheet). If you supplied the module with a higher voltage, it may have been damaged.
3 It is necessary to connect the GND of the ESP32, the GND of the regulator (LM2596) and the GND of the WS2811. It is best to do this in a star fashion, avoiding unnecessary loops.
4. if you have actually damaged the ESP32 three times, it is imperative to check both the supply voltage level and any spikes (pins) on the supply line.

Detailed analysis of the problem .
1. The type and number of GNDs in the ESP32 .
By default, each ESP32 module (e.g. ESP-WROOM-32) has several GND pins, but they all connect to each other on the internal board. So in practice it doesn't matter which of these pins you connect GND to, as long as it is a physically well routed GND line.

2. Power supply voltage and possible causes of failure .
- ESP32 requires 3.3 V, tolerance usually up to 3.6 V.
- Many modules have a built-in regulator from the 5 V pin to 3.3 V, but you need to check if your module has one (not all ESP32 boards have an identical circuit).
- If you are using an LM2596 inverter, make sure it is regulated to exactly 3.3 V (or 5 V if your ESP32 board allows such an input to the appropriate pin) and not to higher values.
- The potentiometer on the LM2596 can accidentally go out of adjustment - this happens especially with cheaper modules.

3. Connect the grounds in the circuit to the WS2811 .
- The WS2811 diodes (on a 12 V or 5 V LED strip) require a common ground with the microcontroller, here the ESP32. If the ground is incorrectly routed (e.g. through thin, long wires or through another regulator of questionable quality), interference can occur, which in turn can stoke the microcontroller.
- In many projects it helps to route a direct ground line from the ESP32 to the ground of the LED strip (WS2811), especially with longer lengths of.
- In typical circuits, it is also worth taking care to convert 3.3 V → 5 V signal levels (as long as the WS2811 bar expects 5 V logic). For this purpose, for example, 74HCT245 circuits are used.

4. Possible problem with multiple power sources .
- Using a 12 V 10 A power supply with an additional inverter for 5 V and another for 3.3 V (or jumpers) can cause complications. Beginners often have problems with ground loops or an incorrectly chosen common ground point.
- The simplest solution (especially in simple designs) is to supply the whole circuit from a single stabilised 5 V voltage. The WS2811 diodes and the microcontroller (ESP32) can then be powered from the same source, and a 3.3 V regulator is routed to the ESP32 (unless the module has its own).

5. Why could the ESP32 be damaged? .
- Supply voltage too high (e.g. incorrectly adjusted inverter above 3.6 V).
- Lack of correct reference to earth, leading to uncontrolled overvoltage of control signals.
- Insufficient stability of the power supply at low load (pins exceeding 3.6 V).
- Incorrect ground connection while controlling the LED strip from a separate source (although supposedly common).

News and trends .
- More and more projects are using off-the-shelf ESP32 modules with a built-in stabiliser, so you only feed 5 V and don't worry about regulation.
- Many hobbyists start with 5 V addressable diodes (WS2812B) instead of 12 V (WS2811), because then one common 5 V supply is sufficient.

Supporting explanations and details .
- When testing or assembling, it is a good idea to first check the correctness of the LM2596 inverters by connecting a resistive load (~100-200 mA) and measuring the voltage.
- Measurement in the "diode test" mode of the multitester is not reliable for checking logic circuits or LED strips, and for detecting short circuits and interrupts an ohmmeter with as low a measuring range as possible (with the power supply disconnected) is better.

Ethical and legal aspects .
There are no significant legal issues in this project, but it is always worth remembering to comply with safety standards when working with higher voltage equipment (12 V, 24 V).

Practical tips .
1 Measure the voltage at the output of the LM2596 - make sure it is stable and does not exceed the limits for the ESP32.
2. Connect the GND at a single point: preferably near the power supply, shorting the ground paths for the measurements and signals to be made.
3. consider using a logic level converter (e.g. 74HCT245).
4. If you don't have a lot of experience, consider switching to a circuit with a single 5 V supply line (both to the ESP32 with built-in stabiliser and to the LEDs).

Possible caveats or additional comments .
- If there are very long LED strips in the project, care must also be taken to power the strip over multiple lengths to avoid voltage drops.
- It is also worth using RC/LC filters on the power line to the ESP32 if the operation of the switching power supply is unstable.

Suggestions for further research .
- Checking the operation of the ESP32 and the power supply with an oscilloscope to rule out brief overvoltages.
- Analysis of the WS2811 documentation (known as datasheet) for logic signal recognition threshold at higher diode supply voltage.

Short summary .
- The ESP32 actually has only one ground, regardless of the number of GND leads.
- It is imperative to ensure that the supply voltage is correct (approximately 3.3 V or 5 V input if the module has its own regulator).
- All GNDs (12 V and 5 V) must be common, i.e. electrically connected.
- If the voltage is too high or the GND is not routed correctly, the ESP32 may be damaged immediately.

Questions to ask the user (if needed) .
1. what ESP32 module exactly are you using (e.g. WROOM, DevKit, other manufacturer)?
2. could you provide your own verified voltage measurement of the LM2596 output during load?
3. do you use any conversion circuitry from 3.3 V to 5 V in the data line to the WS2811? If so, which one?

I would encourage you to re-check both the power supply connections and the exact voltages with a meter in DC mode. Once this information is verified, you will be able to take further steps to protect the ESP32 from damage.